HF-SSB Radio, Proper Installation Tips/Techniques, etc.

[ka4wja]

Hello to all,
This is intended to be an addendum / update to the overall reference sticky, "Marine SSB Stuff (how-to better use / properly-install SSB, & troubleshoot RFI, etc."...
http://www.cruisersforum.com/forums/f13/marine-ssb-stuff-how-to-better-use-proeprly-install-ssb-and-troubleshoot-rfi-etc-133496.html


Here, I'd like to cover / reiterate three important things here, regarding HF radio systems on-board (all of which apply equally to: ham or maritime / SSB; voice or data; monohull or multihull; ...although those with steel or aluminum hulls, please note that the "grounding" topic doesn't really apply to you....that is all about fiberglass/GRP or wood boats):

1- proper installation tips/techniques (including wiring; antennas; and the "ground" system, etc.)


2- understanding of what HF communications work easiest for laypersons

3- importance of learning "how-to" use your HF radio system properly (just like learning to navigate, trim the sails, anchoring, etc.)

[Please understand that anecdotal reports of "this set-up works great", and/or "do this, it's what I did", and/or especially "this guy down the dock, or this 'expert', told me this", and/or the worst "the ad / brochure for this product says it works better than anything else", all need to be taken with a grain-of-salt!! I'm not saying that someone is intentionally lying to you, but I myself have dozens of personal experiences that would seem unlikely, such as using a vhf/uhf police scanner antenna (inside a house in Florida) on the HF ham bands and talking with dozens of stations all over S. Amer and Europe...or siting an HF radio on a cockpit cushion, with 12vdc power wires clipped to the batteries and just a random 25' - 30' piece of wire stuck in the antenna jack, thrown up on a flag halyard, and working dozens of stations all over Europe, US, Carib, and S. Amer, while sailing between Carib and US east coast...these are all true and many others too....but, this doesn't mean that anyone should assume these are reliable examples of HF communications, nor should anyone spend their time/effort/money installing an HF radio system the wrong way 'cuz some guy down the dock did it that way and he said it works great!! ]


1) With today's equipment (such as M-802 and AT-140, or even when installing an older M-700pro/M-710, or Furuno, or Sailor, etc.), as long as it is working "out of the box", if you follow a few simple installation rules, you should have a good working system (assuming you learn how to properly use it)!!


Some of the installation recommendations from the manufacturers are legal-liability-based, as well as based on shore-side installations where the antenna system (and all transmit energy) is easily radiated by the antenna and/or shunted to ground....this not always the case on our boats, where we have not just the radio, but other ancillary equipment, computers, misc. sensitive electronics (as well as other devices actually radiating their own RF energy, causing us RFI), all within a few feet of the transmit antenna!! So, over the past few decades many have found by both scientific means and simple "trial-n-error", what works and what doesn't....{fyi, I assisted in my first Marine SSB install, as a kid, in 1973....joined the ARRL and spent a few years studying not just for my ham license, but also studying antenna system design, radiowave propagation, receiver design, etc...actually continue to study these things today, even though I teach seminars on these topics, there is always something else to learn, ya' know. }

So, before I delve into the specifics of what to do / how-to do it, please accept these few facts:

--- despite what the Icom (and other manufacturers') manuals state, do not connect any RF ground strap between your remote tuner and the main transceiver....yes, do connect the green ground wire (and other wires) as prescribed, but do not add any other grounding connection between the tuner and radio...doing so can cause ground loops and RFI (both transmit and receive RFI), some have not had an issue and if it's done perfectly it can be a great thing, but most find it's not a good idea at all...and it has not been recommended for over 20 years now, but the manuals still show it.

--- despite the old wife's tail of needing "100 sq ft of copper", understand that this is not needed at all, and is a total waste of time, effort, and money....(more details on antenna grounds / RF grounds below), a low-loss/low-impedance direct sea water connection for your antenna ground / RF ground is best...


--- despite the nice long 12vdc power wiring supplied with the radio, do not use this entire length of wire....if you need wiring this long, use larger gauge wire...(details below)

--- despite what they claim, the KISS-SSB Ground is not a "tuned counterpoise", and does not work any better than (actually worse than) a few random length wires tossed into your lazarette / bilge for a counterpoise!! And, is significantly inferior to a direct sea-water connection / antenna ground...(details below)

--- despite what some may think, most marine electronics dealers/installers (including those at shipyards, yacht manufacturers and commissioning locales) do NOT understand HF radio communications even a little, and most do not follow proper / accepted procedures in the installation and commissioning of an HF radio system on-board...no matter how much you just spent on your new boat, this is a fact of our lives these days...I've seen $1million+ yachts whose radio installs are crap!! And, I've heard (not seen first-hand) that there are some "mega-yacht" installs that work so poorly their commissioning reports are "fudged" so they say they meet GMDSS spec, when they don't!! {FYI, the only "factory-installed or commissioned" HF systems that I've ever seen done correctly were from Hinckley and Swan...some of their older SGC and Sailor set-ups were awesomely done, and some of their newer Icom, Sailor, and Furuno installs were wonderful too!! Was on a Swan 57 that had just finished a factory re-fit and its Sailor HF system looked/worked like it was off the Sailor's engineering floor!} So, just because you have a new boat and/or a new "professionally-installed" HF radio system, this doesn't mean it was done correctly...

Please remember that the Sailmail Primer, and their app notes, include significant radio installation and wiring recommendations / tips...and all I write here is confirmed there.

https://sailmail.com/wp-content/uploads/2016/02/smprimer.htm

https://sailmail.com/wp-content/uploads/2016/02/smprimer.htm#Application Notes



Now, some details:

a) Starting with the radio....find a secure location to mount the main transceiver unit, where it will be away from the weather, but still be accessible to connect wiring to and have adequate ventilation (usually at the Nav Station, or a locker nearby), and securely screw it in place with the supplied mounting bracket (it needs to stay-put in a heavy sea!)...mount the control head (M-802 or M-710RT) at your Nav Station, where you can easily see it and use it!! And, if you ned data comms, and decide to spend the outrageous $$$$ for a PACTOR modem (or will be using a "soundcard digital comms" mode, such as WINMOR, PSK31, etc.), keep the transceiver main unit close to your operating position / Nav Station and near your PACTOR modem, where you can keep the connecting wiring short (~3'), (and where you will be able to see the modem's status lights)....especially the USB cable between modem and computer, to keep your transmissions from interfering with your computer...



b) Always connect the 12vdc power wiring directly to the main house battery bank, this allows for the strongest transmit signal, the least transmit interference (transmit RFI) to other systems on-board, and reduces receive RFI as well...do not connect your HF transceiver's power thru your main 12vdc distribution/breaker panel!! (Use large enough wiring to keep voltage drop for the 30amp load to a max of 3%)



c) Keeping the radio close to your main house battery bank is a good idea, thereby reducing the 12vdc power wiring length (always good)....but, unless your radio is very close (< 3' - 4') you will want to use a larger gauge wire from the radio to the main house battery bank...most installs on average 40' - 50' cruising boats will use 6ga wire from the radio's short (~ 12") pig-tail or dedicated breaker/fuse, to the house battery bank...if you'll be using a PACTOR modem or a "soundcard data mode", place the transceiver main unit so that your USB / comm wiring is short (~ 3') and use longer (and heavier gauge) 12vdc power wiring...



d) Use ferrites on any additional wiring to/from the HF radio (such as tuner control wires, modem, computer, etc.)....btw, I use ferrites on all the cables to/from the HF radio main transceiver unit, they're cheap and cannot cause any issues, only help!


Use a "Line Isolator" on the coax, at the tuner end of the coax...this is like stacking dozens and dozens of ferrites on the coax....it reduces transmit RFI and allows your antenna ground / RF ground to work properly (more on grounds later)....use a ferrite or two on the tuner control wiring, at the tuner end (or on both ends)...

https://www.dxengineering.com/parts/dxe-fcc050-h05-a

https://www.dxengineering.com/search/part-type/rf-suppression-snap-on-ferrite-beads?tw=ferrite&sw=RF%20Suppression%20Snap-On%20Ferrite%20Beads

https://www.balundesigns.com/model-1115i-single-core-isolation-balun-1-5-54-mhz-5kw/

https://www.balundesigns.com/qrp-model-1110-1-1-isolation-choke-balun-1-54-mhz/

http://www.radioworks.com/clitop.html

http://www.radioworks.com/ct-4.html



e) Although they are designed to be weather-tight, install the remote tuner below decks if at all possible....for most boats, this is in the lazarette, stern locker, or even in the aft cabin, etc...



f) Some details about HF antennas on our boats...a simple fact is, that they are all a compromise of some sort! No matter what, our boats are boats....they move, they sail, the get pounded by waves / wind / etc...and we want an antenna that works well from 2mhz thru 26mhz, day and night, in all weather, for communications from 50 miles to 5000 miles (and farther), 24/7/365....and we do this, quite well!! But, we compromise in the process....a few more facts:


--- our antennas start at the remote antenna tuner!! (actually the tuner is part of the antenna!)

--- for many years the "typical length" of our HF antennas is 40' to 45'...and for good reason....this allows decent efficiencies on the lower frequencies (4mhz, 6mhz, 8mhz, and 75m and 40m ham bands) and still allow low-angle-of-radiation for the middle HF freqs (12mhz, 14mhz, and 16mhz)....be aware that longer antennas (55' - 65') are better for the lower freqs at a slight sacrifice for 14 -16mhz....and shorter antennas (20' - 25') are better for the higher freqs (21mhz, 22mhz, 25mhz, 28mhz), but at sacrifice in efficiency at some middle HF freqs such as 12mhz, and a serious sacrifice in efficiency in freqs of 8mhz and below....this is why those with "23' whips" are at a serious disadvantage versus those with backstay antennas twice as long, on the "regional cruising nets" on 4mhz, 6mhz, and 8mhz (or 75m and 40m ham bands)...
Take note that with the solar-cycle on a down-slope for next 2 years and won't be back to where we are today until 2022, and the predictions are that things might not be as good as "normal" even in 2025, worrying about the higher end of the HF spectrum (above 20mhz) for next few years is a fool's errand, and if you're considering a whip antenna for your catamaran, I'd recommend a "rope-tenna" or insulating a stay/shroud, anything that will allow you a 40' - 45' long antenna...

--- Since our antennas start at the tuner....the GTO-15 wire (and the tuner) are the start of your antenna!! And, this lower part (the high current part) is a significant part of the radiation of the antenna, especially on the lower freq bands...
So, keeping the tuner and GTO-15 wiring away from other systems and wiring is important!

Now, as I wrote above, our antennas are a compromise...so you won't get perfection here....just know that you do NOT want to install the tuner (and GTO-15 wire) near your refrigeration compressor, nor autopilot core-pak/computer... And, you should never run the GTO-15 wire along any other wiring....(having it run near / across another wire at a right angle is usually not a problem, but never run near / parallel other wiring!) Ignoring these recommendations will usually cause significant RFI on-board, both transmit RFI (your radio's transmit signal causes other systems on-board to malfunction, etc.) and receive RFI (other systems on-board cause noise / interference in your HF receiver)...


{On my current boat, my AT-140 is in the starboard side lazarette, with my Adler/Barbour Cold Machine in the port laz, about 9' away, and my pilot core-pak is about 8' - 9' forward of the AT-140....that's the best I can do....and, with about 3.5' of GTO-15 wire running pretty clear, but crossing my 110vac shore-power wiring and some other wiring at a right angle, about 6" away....due to excellent antenna ground / RF ground, I have no transmit RFI at all....but I do get some receive RFI / beeps from the fridge sometimes....like I said, this is a compromise!}

--- For our fiberglass boats (assuming you remove any chainplate bonding/grounding wire from your backstay chainplate), there is no need to use any "backstay standoffs"! Whatever transmit energy is coupled to the backstay below the lower insulator will be radiated....so use of backstay standoffs to keep the GTO-15 an inch or two away from the backstay, is unnecessary!! (if you have a steel or alum boat, or have your chainplate grounded, then using some standoffs is good practice, but other than that, they serve no purpose...and are ugly and lines can catch on 'em, etc.)


--- There is NO difference in antenna efficiency between using a large SS rigging wire, versus a 14ga copper wire, for your antenna....yes, copper is a better conductor, but since the RF flows on the surface, the increased surface area of the rigging wire compensates for SS less conductivity!



g) The sea water not only provides a great antenna ground / RF ground, allowing most of your antenna return currents to be radiated....but also the sea water provides a very low pseudo-Brewster angle, that is the angle below which signals fall-off quickly....and in the mid-HF region, over sea water, this about 1 degree!! Yep, that's not a typo, one-degree!! This means that even poor antennas work very well over sea water, compared to on-land!!! (fyi, the pseudo-Brewster on-land, with very-good rf ground conductivity is 14 degrees) So, when I and others comment on how great things work on-board and how much of the optimizing is: a) a matter of degree and b) making improvements in receive signal-to-noise ratio....you'll see what we mean!




h) RE: the antenna ground / RF ground:

Install the remote tuner near the base of the antenna (whether backstay, whip, "alternative backstay antenna", rope-tenna, etc.)....and install the tuner near where you can have a direct sea water connection for the antenna ground / RF ground (whether that contact is via Dynaplate, bronze thru-hull, keel bolt, etc.)


Hmmm, you say...what is "near"?? And, how can I be "near" both of these??

Well, please remember this is all a bit of a compromise, and that every boat is a little different...so, I can only give you guidelines, not absolute specifics to what is "near" and and how to be "near" to both...

--- typically we think of 8' to 10' as the maximum distance you can effectively run a low-loss/low-impedance antenna ground / RF ground connection (typically 3" wide copper strap, 0.012" to 0.022" thick, NOT copper foil) from the remote tuner to a direct sea-water contact (Dynaplate, bronze thru-hull, keel-bolts)...shorter is better....longer does work, but fyi as you go longer note that this copper strap starts to become a more significant part of your antenna ground / RF ground, rather than just be the way you connect to the antenna ground / RF ground (the sea water), so in these cases where you have a longer run of copper strapping, it is recommended to also tie-in any metal tankage, lifelines / pushpits / run-rails / toe-rails (be sure to connect with a tapped screw to connect into the alum, not on top of the anodizing)...

--- Dynaplates (sintered-bronze) are no better than the same size solid plate of bronze...but they're stream-lined, easily mounted, have all the hardware (even "gold-plated" hardware)....they're pricey, but for those of us with Marelon thru-hulls (or no thru-hulls close-by the tuner), an underwater bronze plate is a great idea, whether a Dynaplate or otherwise...

--- typically the less GTO-15 wire inside the boat, the better....the better for both RFI and for actual transmit effectiveness, it's all about the distance from antenna to everything else, 'cuz on our fiberglass boats, it's not about shielding I usually think of 5' to 6' as the maximum....but, here again, every boat install is a compromise....shorted is better, but do not mount the tuner 15' away from the sea water ground contact just to get it 2' away from the backstay...

--- Use of wide copper strapping here is important to allow a low-loss/low-impedance connection to the sea water, as you are using the sea water as your antenna ground / RF ground, where it represents the "other half of your antenna", and you want as much of your antenna return currents radiated by your antenna and not lost in some wire / radiated inside your boat / shunted to ground...(please note this is not about using "radials" / counterpoise, where there is nothing at all wrong with using even small gauge wire....in the case of using the sea water for your antenna ground / rf ground, you want to use copper strapping, as even 2" - 3" wide strap has significantly less RF loss than 0000ga wire!!)

http://www.gacopper.com/Braid-Strap-Wire-Comparison.html

In addition to the many decades of practical use on-board by myself and many many others, there was significant work done in the 1930's thru 1950's regarding vertical antenna grounds / rf grounds for both MF and HF, on shore and near ocean....

And assuming you have short, low-loss connection to the sea water, the use of the sea water as our antenna ground on a mid-sized fiberglass boat has proven to be best solution (those on steel or alum boats, you don't have these issues)....and is always recommended as the first, best solution!

This is followed in second and third place, by the use of strapping to keel bolts, and metal tanks....and/or connecting in lifelines, rub-rails, toe-rails, pushpits, arches, etc...which approach beats the other for 2nd place vs. 3rd place, depends on the boat, and it can vary with different freqs too..

In fourth place are "tuned radials" (they really aren't tuned once you put 'em in your lazarette/bilge/etc.)....in my opinion, this is rather distant 4th place, and should be considered only as a stop-gap measure, such as when doing a temp install for a delivery, etc..(this is what the KISS advertises it is, but it as can be easily seen, they aren't really tuned at all...)

A close fifth place is probably connecting to engine block, etc., or no antenna ground at all...I actually recommend no antenna ground at all rather than using the engine block, as that can just increase on-board receive RFI...

[BTW, please note that you can make contacts and use an HF radio on-board with a vertical antenna, without any antenna ground / RF ground at all....it is of course not recommended ever....and will usually cause problems on-board, but you can still use the radio...and both science and actual real-world testing shows that the difference between the best overall antenna ground (the sea water, with a short, low-loss connection to it) and no antenna ground at all is 4db to 6db...possibly more if higher than typical tuner losses present themselves...

When doing the tests of the KISS-SSB Ground, I found no difference in antenna current between no antenna ground and the KISS....and about 3 to 4 times the antenna current with my direct sea water antenna ground, using my Delta TCT-N rf current transformer and Tektronics scope...this represents 5db to 6db difference...and on-air tests (although subjective and anecdotal) also showed significant difference of appox. 6db...(understand that while my modern spec analyzer does allow me to save the spectral scans and post 'em, which I did....my old Tek scope does not...so, you'll just need to take my word for what I saw on the screen)....these antenna current readings show how much energy is actually getting to your antenna and being radiated, and they represent the same thing as using a fluorescent light tube along the backstay, where the brighter the light the higher the antenna current...the better the antenna ground, the more antenna current, and the better your signal is!! And to digress a bit to the 1970's, before the advent of microprocessor-driven remote auto-tuners, HF systems on-board used remote antenna "couplers" (which is actually what we should be calling our tuners, but that's a whole 'nother discussion!), which typically had 12 positions, switched by a 12vdc solenoid/motor, controlled by the radio's channel knob switch...each of these positions had to be set-up / adjusted, by placing a tap on a coil and tuning/adjusting two capacitors...and while they used a Bird 43 wattmeter watching the reflected-power, final tweaking was done with the radio transmitting a carrier and watching how bright the fluorescent tube got! No kidding, I personally watched this procedure with my own eyes in the 1970's...my, the more things change the more they stay the same, huh?]

Have a look here for lots of detailed test results on the KISS:

https://www.ssca.org/forum/viewtopic.php?f=5&t=13490&sid=71ce07723774224320e6 23c07bed5242&start=75


Actual results in the open air:
https://www.ssca.org/forum/viewtopic.php?f=5&t=13490&sid=89afd1b4627060f83ac9 03b2344eb03a&start=75#p74444


Actual results in my lazarette:
https://www.ssca.org/forum/viewtopic.php?f=5&t=13490&sid=89afd1b4627060f83ac9 03b2344eb03a&start=75#p74499



Please also have a read of Gordo's old, but still very viable, tests comparing various antenna grounds....and what Sailmail recommends...

http://sfbaysss.org/resource/doc/SeawaterGroundingFor_HF_Radios_byGordonWest.pdf



https://sailmail.com/wp-content/uploads/2016/02/smprimer.htm


https://sailmail.com/category/installation/

https://sailmail.com/equipment-choice-and-installation-for-accessing-sailmails-radio-network/


Please take note that while I'm fully confident that in addition to the science behind all of this (which I've studied for ~ 45 years now), the actual real-world practical results back-up the science quite well! And, also please remember that when comparing transmit performance, this is a matter of degree, but understand that a 6db difference is the same as going from a 150-watt radio to a 37-watt radio...and there are times when this small difference will be the difference between making contact or not... Further, remember that anything you can do to improve your receive signal-to-noise ratio (by improving antenna and ground system, reducing on-board RFI, etc.) is always worth it, always!!


Please take note that I use the word "strap" or "strapping" and not "foil"....this is because foil is too thin, too fragile, and too difficult to protect from corrosion, to be considered a long-term ground connection...If you use 0.012" think copper strapping it will last a long time even if you leave it bare! I recommend painting a few coats of clear lacquer on it before you install it (except of course for the ends where you make the connection, where you can paint or cover those connections later)....btw, if you use even a ticker strapping (0.022", etc.) like I did with my 6" wide strapping that runs from my AT-140 about 7' to my two Dynaplates (all Marelon thru-hulls), and my 3" wide strapping to the keel bolts, it will last decades even if you don't paint it! Please don't use foil, don't buy your copper from West Marine, but it from a copper company! (in the US, I recommend Georgia Copper!) Oh, and never, ever use braid!!

http://www.gacopper.com/

http://www.gacopper.com/012-CopperStrap.html

http://www.gacopper.com/022-CopperStrap.html

http://www.gacopper.com/Braid-Strap-Wire-Comparison.html



--- Remember what the antenna ground / RF ground is supposed to do:

1 - provide "the other half of the antenna"....allow antenna return currents to be radiated..
2 - assist an antenna couple / antenna tuner in making an adequate match, and reducing tuner losses....
3 - reduce/eliminate feedline radiation.....
4 - shunt "un-radiated" RF to ground (reducing RFI, etc.).....

(although, some may question the "necessity" of this item #2 these days, as our modern auto-tuners could match a "coat-hanger", etc.....what this gives us is, the ability of the auto-tuner to find a more efficient tuning regime, thereby allowing more of our transmitted power to be properly coupled TO the antenna...)

But, also remember that the effectiveness of our antennas is a matter of degree....so, arguing about "proper" antenna grounds can be a frustrating experience....you have the factual info, and the recommendations of those using/installing HF systems on yachts for decades, but it's up to you to decide what you want...




I hope the above will help clarify what are the accepted practices and best installation techniques for HF-SSB-DSC Radios...



~~~~~~~~~~~~



2 & 3) Over the years I have often stated that learning about HF radiowave propagation and "how-to" properly use your HF radio (whether for ham or maritime...whether voice or data), is overwhelmingly the most important part of an HF radio system on-board!!

And, I continue to stand behind these views (but, there is a caveat)!

An old, crappy HF radio, poorly installed and/or maintained, in the hands of a skilled/experienced operator will work / will make contacts, and usually with some ease....But, conversely, a new, perfectly-working radio, properly installed, etc., in the hands of an inexperienced layperson, will have difficulty in making contacts...but, there is that caveat!!

What is this caveat??
It's HF-DSC!

Oh no, he's not going to rant again about HF-DSC, is he? The answer is: No...but..

But, the fact is that the GMDSS (Global Maritime Distress and Safety System) was adopted by the IMO and SOLAS conventions in 1988 and implemented in the 1990's to allow for better Safety Of Live At Sea (SOLAS), and part of this was both redundancy and ease of use / ease of signaling distress / ease of communications...The GMDSS consists of multiple parts that we as pleasure boaters can use very effectively!!

https://www.navcen.uscg.gov/?pageName=GMDSS

http://www.ccg-gcc.gc.ca/eng/CCG/SAR_Gmdss

HF-DSC signaling can be done by any layperson sailor....and a DSC-Distress Call (especially a six-freq DSC-Distress Call) will get thru to just about everyone (every SOLAS vessel in your region, as well as coast stations / RCC's), without any real operator technical knowledge!!
But, with the exception of HF-DSC, the above recommendations to learn about the radio, how to use it, and about radiowave propagation, all still hold!!

FYI....those interested in the GMDSS, DSC, and how you can use these inexpensively and effectively on our boats....have a look here:

https://www.ssca.org/forum/viewtopic.php?f=5&t=17183&sid=969f049a08d7b25a22ca 4e67cdf721f3

Here's a excerpt:

Parts of the GMDSS system that most find easy/affordable/useful (all within easy reach / affordable parts of the GMDSS for cruising boats...):

--- 406mhz EPIRB's (relatively inexpensive at $400 - $700, and easy to "sell" to cruising sailors..)

--- Marine VHF-DSC-FM (cheap and almost ubiquitous now-a-days....anyone that doesn't have a Class D VHF-DSC-FM radio, really needs to spend the few hundred dollars now!!

--- Marine MF/HF-DSC-SSB (HF-DSC is a VERY robust/reliable means of signaling.....and with reasonable costs of ~ $1800 new, ~ $1000 used, for an Icom M-802 MF/HF-DSC-SSB Radiotelephone....and simple-to-use, robust and reliable...it is an easy "sell", almost a no-brainer!!)

--- NAVTEX (inexpensive and very useful for most coastal sailors and/or those plying the Med, etc., with typical forecasts for waters out to 150 - 200 miles....but in some areas the forecasts are only for the next 24 hours, so other weather sources, such as HF-WeFax are recommended...) (and in US waters, the VHF-based NOAA Weather Radio system is widely used, so NAVTEX hasn't caught on in the US, as it has in Europe and the Far East...)
- WeFax....And while HF WeFax was not adopted officially as part of the GMDSS, according to a 2012 survey by the Joint WMO/JComm group, HF comms, DSC, voice, and data are used daily by a majority of ocean going vessels, and HF wefax being reportedly used daily by > 85% of them....so, for offshore/hi-seas weather info/forecasts beyond the "text" weather info provided via INMARSAT-C and some HF coast stations, HF WeFax still rules as the predominate "1st choice" when offshore, even in 2012, even for large ships / SOLAS vessels....)

Parts of the GMDSS that are a bit more expensive:

--- INMARSAT-C,
While INMARSAT-C might seem to some to be a bit pricey, at ~ $3000 - $3500, is a VERY viable communications tool to have on-board long-range cruising boats...as it gives, thru its FREE "SafetyNet" service, offshore/hi-seas weather info/forecasts (in plain text), position reporting and weather reporting thru NOAA and AMVER, and Distress Signaling....ALL FOR FREE....
NO monthly/annual subscription, NO Fees at all, until/unless you use it to send regular e-mails, and then you're just billed by the character/letter....
(and it is very robust/reliable....many orders of magnitude better than a handheld sat phone!!)


--- INMARSAT Fleet systems (such as F77) are pricey at $15,000 - $20,000 and are big/heavy, and use significant amounts of electrical power....
So, here if cruiser's desire hi-speed data / broadband internet access / etc., Iridium Pilot or INMARSAT Fleet Broadband systems (at ~ $4500 - $5000) are usually the typical choices....
FYI, INMARSAT is phasing-out their Fleet33 and Fleet55's and both the FleetBroadband and Iridium have submitted their systems for GMDSS certification...

--- SART's (X-band radar Search And Rescue Transponders) are reasonably priced at $600 - $800.....but are often over looked by many cruising boats, as they figure a working EPIRB in their liferaft will do them better...
And, if deciding between a second 406mhz EPIRB and a SART, I'd choose the second EPIRB...(but, if you're cruising in heavily-trafficked areas, with poor visibility, such as UK/North Sea, etc. then a SART would be a GREAT idea, and I'd recommend one before a second EPIRB...)
Also, note that while an AIS transponder is great for the vessel, the MOB-AIS devices might be good to find you if you're a mile or two away, the second EPIRB or a SART, will be better!

Anyone talking about "Marine SSB" in the last decade or two, should be talking about MF/HF-DSC-SSB....and those that are talking about 25 year old radios and "Voice radio watchstanding", etc. are unfortunately either ignorant of the changes in the past 25 years or are laboring under some serious misconceptions???

While it is not a requirement for our pleasure craft, the GMDSS has been a mandatory system for all SOLAS vessels, and all signatory nations, since Jan 1999....over 15 years ago...and regarding "SSB", please remember that nobody (except the USCG, Aus and NZ, and Bermuda Harbour Radio) does any "SSB Voice" monitoring or watchstanding anymore...and haven't for decades....

As for learning how to use the radio, and radiowave propagation, etc. please read this sticky...and watch these videos...

"Marine SSB Stuff (how-to better use / proeprly-install SSB, & troubleshoot RFI, etc.)"
http://www.cruisersforum.com/forums/f13/marine-ssb-stuff-how-to-better-use-proeprly-install-ssb-and-troubleshoot-rfi-etc-133496-5.html


And, please watch these video playlists (where the videos are laid-out in an easy-to-understand and logical order):

HF-DSC Comms
https://www.youtube.com/playlist?list=PLnN6ygtZ3h2n3z5nlv-ga2zYuPozhUXZX


Maritime HF Comms
https://www.youtube.com/playlist?list=PLnN6ygtZ3h2nPNdApNsZDo_Jk3NB_Bt1y


Icom M-802 Instruction Videos
https://www.youtube.com/playlist?list=PLnN6ygtZ3h2npivDjoFrC-8QKVyMb4tVr


Offshore Weather sources
https://www.youtube.com/playlist?list=PLnN6ygtZ3h2mPZAx2vWzdjTJjHlChruyY


VHF-DSC
https://www.youtube.com/playlist?list=PLnN6ygtZ3h2m-IejYg7J6QugtO2epizxF


Offshore Sailing
https://www.youtube.com/playlist?list=PLnN6ygtZ3h2nbwAGh5DKgTCj15iyl6qoY




I do hope everyone finds this reference helpful....and hopefully some moderator will add it as a "sticky"?


And, finally....
Please read what happens when you activate your EPIRB, etc...
EPIRB Activation? What happens/How to improve rescue odds
https://www.ssca.org/forum/viewtopic...t=15457#p77305


Fair winds.

John

[ka4wja]

Not sure how all the paragraphs of info dealing with the DSC receive antenna and GPS connection to the HF-DSC radio (M-802), got deleted...oppss.

So, here 'ya go!


--- On all Class E (and Class A) MF/HF-DSC-SSB Radiotelephones (the M-802 is a Class E), you have the main antenna, which handles all transmitting (Voice, data, morse, etc.) and all receiving, except for the continuous monitoring of the six GMDSS DSC calling freqs (2187.5khz; 4207.5khz; 6312khz; 8414.5khz; 12577khz; and 16804.5khz) all the time the radio is turned on....

Even though you do not see it doing so, the radio has a separate, dedicated six-channel scanning receiver, built-in, that is continuously monitoring these six Int'l GMDSS DSC calling freqs, and this separate, built-in receiver has its own separate antenna connection ("DSC antenna"), and therefore requires its own separate HF-DSC receive antenna...

[fyi, this DSC-receive antenna is needed to receive an "ACK" (acknowledgement) of your DSC-Distress Call...and, while you receiving this "ACK" is not an absolute necessity for a SAR operation to get underway, the fact is that your radio will continue to transmit your DSC-Distress Call until either an "ACK" is received, or you cancel the DSC-Distress Call yourself, and unless you receive this "ACK" you will not necessarily know what SSB-Voice freq/channel to coordinate your distress / SAR operation on, as the "ACK" will be received on the best freq/band for comms, and your radio will then automatically being standing-by on that SSB-Voice channel...so, having a DSC-receive antenna is a good thing!!]


Due to the robustness of the HF-DSC signal, compared to SSB-Voice signal (and of course, most replying to any DSC-Distress Call, will be more powerful coast stations and/or large SOLAS-grade merchant vessels), this "DSC-receive" antenna does not need to be as large, nor as efficient, as your primary/main antenna...

So, many have found the small (54" tall) Metz "DSC / WeFax" receive antenna, mounted in the clear on the stern rail or arch, etc., to be a very usable solution!! (I used this myself for about 4 - 6 months, and it did work fine...but I changed things to allow for better WeFax reception, as well as better HF-DSC reception..)

http://www.metzcommunication.com/weatherf.htm

In theory with HF-DSC being 100 baud SITOR-FEC, and the M-802 DSC receiver bandwidth of 500hz (or less), you should have a S/N advantage of 12 - 15 db. versus an SSB voice transmission using the same power, distance, etc.....so....

So, in theory, if your DSC Receive antenna was no worse than 12db down from your main SSB antenna, whatever comms you could successfully complete on SSB (voice), should also be capable on DSC...

And, having your DSC-receive antenna mounted out in the clear, away from RFI sources on-board, etc., should improve your DSC-receive signal-to-noise ratio!!

https://www.navcen.uscg.gov/?pageName=cgcommsCall

https://www.navcen.uscg.gov/pdf/marcomms/CGSafetyAlert0817.pdf

https://www.navcen.uscg.gov/pdf/marcomms/2MHzDistressWatchkeepingClosureSafetyAlert.pdf



Please watch these videos in this playlist...where you'll learn a lot about HF-DSC..

HF-DSC Comms
https://www.youtube.com/playlist?list=PLnN6ygtZ3h2n3z5nlv-ga2zYuPozhUXZX




{So, installing anything better than the above antenna is probably over-kill....but, you know me, I'm a radio nut....and since I wanted better WeFax reception, I changed things on my boat....I found a 22' long vertical wire (an insulated aft-lower-shroud) to be an excellent HF-DSC-receive antenna (and WeFax receive antenna)....but, this is over-kill and most will never do this!! }




There are other options of course, and if you do not have access to the Metz antenna, or do not wish to spend the $$ on it, you can try just using your entire rig as a DSC-receive antenna....(not the best approach, but is do-able)
By just running a coax from the M-802's DSC receive antenna jack, to a shroud chainplate, and just attaching the center-conductor of the coax to that chainplate, thereby using that shroud, and your whole rig, as your HF-DSC receive antenna...(or using a balun at the shroud, and attaching only one wire from the balun to the chainplate, or attaching the other wire from the balun to a keel bolt, is a good idea....or at least a few ferrites on the coax, at the chainplate end of the coax)

In this case, as you're using your entire rig as a receive antenna, it is likely that you will have some added receive RFI with this antenna, but the narrow-bandedness of the DSC signal and its robust nature of demodulating, should partially compensate for this...(again, this is not the best approach, but is workable)


[A good way to tell how well your DSC-receive antenna is working:
Compare your on-board receive RFI between your main antenna and DSC-receive antenna, by simply swapping the cable on the back of your M-802, and listening to your RFI...AND..
And, tune-in to an active station that is transmitting for a few minutes (USCG HF Voice Weather broadcasts, WLO, WWV, etc.) and compare the signal strengths and noise levels, when swapping antennas back-n-forth, a few times over a few minutes...
Remember, even if the smaller antenna's signals are weaker, the noise pick-up might be less as well, and this is the important part....it is all about the signal-to-noise ratio!!]






--- GPS data input to your MF/HF-DSC-SSB-Radiotelephone...

The M-802 requires NMEA 0183 vers 3.01, NMEA position sentence GGA..

This in input via the BNC connector on the main transceiver (an odd connector for this, but it works), with NMEA + on the center pin, and NMEA - on the shield...

I recommend a separate, dedicated GPS receiver to feed this NMEA data to your DSC radios (both HF and VHF), as this allows your radios to always have accurate/up-to-date position data in them 24/7, without the need to have any other marine electronics operating (such as when sailing offshore on long passages, such as across oceans, when you will not be running a chartplotter, etc...and/or in the case of distribution / breaker panel issues, as you have your HF radio wired directly to the house battery bank, so as long as you have 12vdc of some sort, the radio will work and if you have a dedicated GPS receiver driving NMEA data to it, you can always send a DSC call with accurate position data...

I use a Garmin GPS-76 series handheld GPS, mounted at the Nav Station and powered thru the ship's 12vdc (and also has internal battery power)...no need for an external antenna on fiberglass boats..








Fair winds...
John


{ P.S. Please note my reasoning for doing what I did was both serendipitous (my aft lower shroud allowed me a good length for what I wanted, about 20' - 22'), and met my easy / no-muss (and no failure) design criteria....

My design thoughts were: with my primary WeFax freqs being 8.5-9mhz and 12.7mhz (with some daytime 17mhz and some nighttime 4mhz and 6mhz)...and with 8414.5 being a primary HF-DSC freq, (with 2187.5khz being a secondary, and a primary in Europe), and end-fed vertical antenna of 30' or less would do well, and provide a decent low-angle....and an end-fed wire of 18' - 27' long would be excellent, easy / low-loss match to 50-ohm coax on 12mhz thru 8mhz freqs, and still not be that low impedance on the lower freqs....and since atmospheric noise rises significantly on these lower freqs, any possible (and small) mismatch loss would actually be a positive....
So, in my case, my aft lower shroud worked perfectly for my application...
BTW, the first MF/HF-DSC-Distress Call I received (actually a Distress Relay Call) was in summer of 2007...at night, rafted to the quay in Horta, Azores....I was listening to some SW stations (with headphones on), and the damn Distress Alarm went off...scared the crap out-of-me!! and woke my crew up, thinking we were on fire or something!! }

[flyingnut40]

Following

[hellosailor]

Nice, but could you chop the photos down to a thousand or so pixels wide? They blow the entire screen out, so all the text also gets blown out to their width, and then it is scroll-scroll-scroll in order to read the thread, which can be very annoying.

[ka4wja]

Okay, anything that makes life easier is okay with me!
Something annoying, is bad!
And, I'll try to do better...

But FYI, I don't seem to have this problem...
Not sure if it's a Cruiser's Forum configuration that we have set differently??
Or a browser set-up difference?? (I checked with all 3 of my browsers, IE, Firefox, and Chrome...and I have no issue with any of them)

'Cuz I see the pics in their "reduced size", with the beige bar above 'em, saying "This image has been resized. Click this bar to view the full image. The original image is sized %"
And, the text is in normal width paragraphs, etc...
Only if clicking on that bar do the pics expand to original size, and then I see the text spread out...

Any ideas???

John

[hellosailor]

Damfino. I'd suspect it has to do with forum setup options, yours apparently resizing images and mine not, perhaps?

If I look at the most recent picture above, it says it is
http://i65.tinypic.com/16bk075.jpg
and that shows properties of 1395 pixels wide. I *can* set my browser to a reduced view and make that one fit in one screen, but there are wider ones up above it. Some of our older eyes can't read the tiny type when screens are shrunk down to display 2000 pixels across.

I know that superVGA (600x800) is obsolete...but wonder what is considered normal or typical for screen displays these days?

[Scott Berg]

John,

great post. For those who don't know, there is a lot of manure about HF radio. Hams and the Military have been doing it for 100 years and have it right. For some reason there is a lot of poor info floating about considering HF radio in the maritime service and many people here who parrot what they've heard but never actually tested in real world situations.

Listen to John (KA4WJA), Bill (WA6CCA), Dave (KM4MI), and, maybe even me (WAØLSS)
<grin> . John has spent a LOT of time helping people understand the ubiquitous Icom M802, Bill is an antenna wizard, Dave a digital comm's expert.

[daletournier]

Hi John, thanks for all the info, that's some serious effort you've put into helping others. I appreciate the information.

Sukha is installed with the Icom M802 and pactor modem. I have put very little effort into learning about the system, always relied on satelite. Your thread is timely, as learning and operating the system is on my" to do list", I intend to start getting a handle on it during the next six weeks prior to next passage.

Cheers Dale.

[ka4wja]

Scott, Dale, et al...
Thanks for the kind words!

{and as a reminder to all, the other sticky and the videos have most of the info about operating / troubleshooting...}
Marine SSB Stuff (how-to better use / proeprly-install SSB, & troubleshoot RFI, etc.)
http://www.cruisersforum.com/forums/...tc-133496.html


But, since everyone is reading this one about installation techniques, thought I'd add some brief reminder info here, too..


I'd like to add a few "US-Based" pieces of info, but they do effect most offshore sailors worldwide!

The USCG published a Marine Safety Alert last year, advising all mariners of their recommendations for proper signaling / calling of the USCG, SOLAS vessels, etc., along with links to their specific MMSI#'s and freqs...

Have a look (the red bold-type is the USCG, not added by me!):

Know your high seas comms equipment and how to use them.
You just might save your own life when in trouble offshore!
https://www.navcen.uscg.gov/pdf/marc...yAlert0817.pdf


https://www.navcen.uscg.gov/?pageName=cgcommsCall



And, of course their announcement from June 2013, of their discontinuation of all MF/2mhz operations....no more 2182 SSB, nor 2187.5 DSC...
https://www.navcen.uscg.gov/pdf/marc...afetyAlert.pdf

USCG Discontinued ONLY 2mhz Distress Watchkeeping 8-1-2013



I hope the above helps....
And of course is a reminder, that HF-DSC signaling (or MF/HF-DSC signaling) is what is needed in almost all places around the world, at sea....and except for the few SSB-Voice freqs monitored by USCG, AMSA, NZMA, WLO/KLB, (and Bermuda Harbour Radio), everyone else is monitoring MF/HF-DSC, not SSB-Voice...[there are > 450 MF-DSC coast stations in operation world wide, and > 80 HF-DSC coast stations worldwide, and 1000's of SOLAS-grade merchant vessels around the world, and while they do have SSB-Voice capability, they're all monitoring DSC, not SSB-Voice channels!]
Of course, there is always the ham radio bands, where you're sure to find someone....but in a "Distress" situation, I'd rather my Distress Call gets to all other vessels in my area and directly to the RCC...and include my accurate position data, along with MMSI# (which gives them all details of my boat, my safety gear, my comms gear, etc.)

Fair winds.

John

[exMaggieDrum]

Hi John,
I am about to install my second M-802 but the first one was in 2003 and I sold the boat in 2008 so I don't remember much. You have provided excellent advice and sources and I am taking notes to use in my installation.

Just FYI - Radiowork.com says he is retiring and most products are no longer available, including the ones you referenced:
http://www.radioworks.com/clitop.html

http://www.radioworks.com/ct-4.html

Also, this isolator from dxengineering is no longer available:

https://www.dxengineering.com/parts/dxe-fcc050-h05-a

I think I am going to get one of the other baluns you suggested from dxengineering.

Thanks for all the work you put in to your radio comments and advice for all of us novices.

[ka4wja]

While this update, regarding channel/frequency choice and radiowave propagation, has more to do with operating the radio than installing it....the fact is that with the down-slide of our sunspot cycle, it is the lower frequency bands that we will be using more and more...AND

And, with the generally higher noise levels on these lower bands, it will become important for many to maximize their HF radio system's efficiency and effectiveness for these lower freq bands....

So, when designing your HF system for use now thru 2021 / 2020, it is longer antennas, better antenna/RF ground system, and more attention to reducing on-board receive RFI....these are the things that will matter...

BUT...

But, of course, educating the radio operator will go a LONG way to mitigating any deficiencies of your HF radio system, whether maritime or ham!
So, with that in mind....here is some updated info and a new, updated video describing channel / frequency choice and radiowave propagation in the coming few years...



As you can see from this graph, when I recorded most of these videos in Oct 2013 (and again in early 2015), the sunspot cycle wasn't great (avg SSN of 55 to 60), it was much higher than today, in 2018...




So, this month (July 2018) I did another video, updating and describing current HF radiowave propagation for the offshore mariner (whether they use maritime or ham bands)...

This new video, together with my earlier video regarding channel / frequency choice and the basics of Radiowave Propagation, should give many of you some assistance in getting the most out of your HF communications system on-board.


Have a look:

https://www.youtube.com/watch?v=fMTWgIvyro4

I also added the new video to these Playlists:

Icom M-802 Instruction Videos
https://www.youtube.com/playlist?lis...rC-8QKVyMb4tVr


HF-DSC Communications
https://www.youtube.com/playlist?lis...ga2zYuPozhUXZX


Maritime HF Communications
https://www.youtube.com/playlist?lis...ZDo_Jk3NB_Bt1y


Offshore Weather
https://www.youtube.com/playlist?lis...zdjTJjHlChruyY




I hope this helps.



Fair winds

John

[alctel]

Hey

So I have stray RFI all over the place when I try to transmit - on 14Mhz channels (like for instance when I try to use my pactor modem on those frequencies) it actually sets off the completely independent, battery powered (not connected to the boat 12v at all) carbon monoxide detector, kills the autopilot and crashes the computer! Even on lower frequencies it's less dramatic but causes some LEDs to pulse etc. Way worse on the higher frequencies though.

I don't seem to have much RFI on receiving.

I have followed a lot of these guidelines - Line Isolator (though on the radio side), ferrities all over the place, I use the 'alternative backstay' idea as the antenna (basically a bit of coated lifeline hauled up the mast), the radio is not hooked up through the distribution panel. The ground wire is only hooked up on one end, not to both the tuner and the radio as the manual says to and the tuner (and therefore the antenna wire) is far from all other wiring.

However I use a KISS as a ground - would this have something to do with it? Due to the location of the tuner I could attach the tuner to either the aluminum toe rail via the throughbolts or a bronze seacock (I'd prefer the former as it is easier). Would that make a difference?

[ka4wja]

alctel,
3 Things:

1) I'm in the middle of some family medical things this week, so I need to be brief...(and since I'm not on your boat, and cannot do any "testing" myself, much of the advice below is based on both sound engineering and my experiences....but, could be wrong for you, as I'm not there and cannot see / test for myself....


2) Transmit RFI can be either "directly radiated" (comes directly from your antenna into other devices/systems)....

Direct radiated xmit RFI can only be cured in a few ways...nothing you can do with the radio or tuner, etc....it is all "distance" and "protections"..

a) Increasing the distance between the xmit antenna and the devices/systems (usually not possible on out boats, but since you're using an "alt backstay antenna" you have an advantage that most do not....you can move your transmit antenna!! Sometimes just moving it from starboard aft rail to port aft rail can work...try different locations and if the length is odd, try different lengths, too)
And, making sure you do not have any of the antenna (this includes the GTO-15 wire!) running parallel to other wiring....perpendicular is usually okay, but not parallel...
{fyi, my main GPS SeaTalk wiring runs within 18" of my GTO-15 wire, perpendicular....and never an issue at all! and my solar panel wiring runs in a sort-of zig-zag route for a few feet to keep from being parallel to the backstay for too long....it takes care and planning, but can be done!! }


b) Shielding the affected devices (usually not too practical, but can work well as long as you also isolate/choke off all wiring to/from the devices/systems)

c) isolate / choke off the RF flowing on all the wiring going to/from all the devices / systems effected....and doing this immediately as the wiring leaves the device....using clip-on ferrites (mix 31) is good, but you're MUCH better off running these wires multiple turns thru a larger ferrite core (2 turns thru a ferrite, is like 4 'clip-on" single pass-thru ferrites....4 turns is like 16 clip-ons, and so on...)

d) of course, not having lots of extra wiring connecting the effected devices / systems is always good....but if you need extra wire to allow ease of install/service, try to coil it up tight and run the coils thru a ferrite...

e) there are also some rather odd occurrences of xmit RFI where simply re-routing some wiring solves the problem....and this is usually because a good deal of your xmit RFI was re-radiated RFI (see below) rather than directly radiated...



3) Or, transmit RFI can be "indirectly radiated" / induced (such as RF on the outside of the coax, and//or control cables, especially those with no ground/shield connections or poor ground/shield connections), into these devices/systems.....and this includes "reradiated" RFI, which comes from your transmit signal (having left your antenna) being picked up by another metallic object (usually a resonant length of wire?) and then "re-radiated" into systems / devices on-board...
a) indirectly-radiated RFI (not exactly the proper term, but I'm using it for clarity) can be a pain, but what you want to accomplish is rather straight forward....
you simply want all your RF to be radiated by your antenna, or shunted to ground...(and in the case of our end-fed vertical antennas, this ground current is then reradiated by the antenna, making a "complete circuit"...again, not technically a great description, but for this discussion it will do...)
SO...

So:
b) placing a "line isolator" at the radio end does you no good (except possibly reducing RF feedback into your own transceiver)....
you must install the line isolator at the tuner....as close to the tuner as possible....any cable (coax) between the line isolator and tuner will potentially radiate RF and hence can be a real RFI issue!

c) not connecting a shield at both ends of a cable is a mistake....I know it has become common-internet-advice (and many will argue all day about "causing ground loops", etc.)....but, please connect all shields of all shielded cables at both ends, otherwise it's just like not having a shielded cable and any ferrites placed on this cable would have little, if any, effect....
(trust me, clean, proper grounding/shielding is a good thing here!)
Remember, we are not using these cables' shields as part of our antenna ground / rf ground, 'cuz they're gonna have ferrites on 'em and/or they'll be run a few turns thru a ferrite (place the ferrites AT THE TUNER END, NOT AT THE RADIO END, except in the case of RF feedback, etc. to mitigate RF getting back into the radio, then place 'em at both ends!)....but rather are using the shield to "shield" rf from getting back into the radio, etc....understand that just connecting the shield of the tuner control wire (and any other wires connected to the radio and/or modem) will most probably, in-and-of-itself, make little to no difference to your transmit RFI....BUT, having the shield properly connected then allows the ferrites to do their job and actually keep the RF from flowing on the outside of that cable's shield....




d) having somewhere for the antenna currents (antenna ground currents) to go is vital for both an efficient/effective antenna, AND to reduce/eliminate xmit RFI...as it gets your transmit signal radiated out of the boat by the antenna, and not inside on the "ground system" / counterpoise / etc. (this usually doesn't happen, but when using a poor antenna ground, you can end up with a good deal of RF trying to be radiated and "opps", now you've got RF into lots of stuff... )
So, getting a better antenna ground is ALWAYS a good idea when dealing with xmit RFI...
If you're in salt water, a direct sea water connection is great....if you make this a low-impedance connection (such as a piece of 3" wide copper strap, directly from your tuner ground lug to a clean underwater bronze thru-hull), you will be in much better shape!!
(if you choose to try the toerail first (for convenience sake), please know that you must attach to the aluminum itself, not just the surface as the surface anodizing will not make a good RF connection....and since most toerail screws/bolts are "bedded" it's likely they're not making any good RF connections either, so....so, drill-'n-tap a new screw into the toerail and grind/sand off the anodizing around the hole, to allow good RF terminal contact....(and I recommend a anti-ox electrical compound on this connection to, like Penatrox-A)

e) start with just the radio, tuner and antenna, with the line isolator at the tuner end, shields connected and ferrites at the tuner end....nothing else!!! not even any antenna ground, no KISS, no PACTOR, nothing!!!
See how the radio works, on ALL bands and all frequencies you use...move antenna if needed...

Then add a good antenna ground (like a direct sea water connection, etc.), not the KISS....and see how it all works then....


Then and only then, connect your PACTOR modem, and power it up....but do NOT try and connect to a PACTOR station, but rather use the radio as in these other tests, and see how it all works then...


Then connect your computer (if hardwired) to the PACTOR modem, and do all these tests on ALL the bands and all your usually freqs, and see how it all works....


And, finally, once you've gotten everything working satisfactorily, then and only then attempt to connect to a PACTOR station and see how it all works...


{I hope you see what I driving at....take a "systems" approach, but start with the basic system, and add one thing at a time into the mix....figire out how to eliminate / mitigate any RFI caused from each "thing" as it is placed into the system....don't start from the end and try to figure out what to do with the whole system from the get-go, start from the basics!!)




f) finally, please understand that in many cases like yours it isn't just "one thing", but rather a combination of things that is probably causing these issues....and therefore taking a "shot-gun approach" seems like good idea to most....but, I prefer starting from the basics, see what works and then add things 'til it doesn't....
In this case, it means getting your antenna a good antenna ground, first!!!




4) Now, having written all the above, I do have to tell you that sometimes, some radio installs are plagued with RFI issues and while the owners have done a lot to eliminate / mitigate things, sometimes things don't seem to get better....and then...
And then they either fix it without knowing how or it fixes itself....and this is usually because there was a loose/poor connection some where!!!
(that could be a rigging connection, antenna connection, interior wiring connection, etc....most of which have nothing to do with the radio itself!! sometimes things "just happen"...




Hope this helps...
Gotta go!

John

[alctel]

Wow, lots of great suggestions there, thanks. Will give them a shot.

[alctel]

I've reconnected the shield at both ends, moved the line isolator to the tuner end and it was still tripping the alarms.

I then disconnected the KISS and tested, then connected a wire to the tuner and dropped it overboard into the ocean for a direct connection. Still was tripping the propane/methane detectors.

I think it may be directly radiated RFI - the methane detector is a completely stand alone battery unit and is at least 6' away from any other wiring and is mounted on the cabin wall though I'm not sure how I can choke it - there is no external wiring!