Cruisers Forum
 


Reply
  This discussion is proudly sponsored by:
Please support our sponsors and let them know you heard about their products on Cruisers Forums. Advertise Here
 
Thread Tools Search this Thread Rate Thread Display Modes
Old 30-11-2020, 13:28   #1
Nearly an old salt
 
goboatingnow's Avatar

Join Date: Jun 2009
Posts: 14,368
Images: 3
Testing my boats HF on land

I知 hoping to test my icon 7000 AT140 setup on land before bringing it all to the boat ( which is a long way away )

I知 using a HF whip ,

Could inset this up on land , what would I need for the counterpoise , an earth rod maybe

Thanks

Dave
__________________
Interested in smart boat technology, networking and all things tech
goboatingnow is offline   Reply With Quote
Old 01-12-2020, 21:08   #2
Registered User
 
ka4wja's Avatar

Join Date: May 2007
Location: Florida
Boat: Catalina 470
Posts: 2,477
Re: Testing my boats HF on land

Dave,
The short/quick and simple answer is....
You can just throw some random lengths of wire down on the ground, and connect them to the ground terminal of the AT-140 tuner, and you can test away....(or even no counterpoise at all, will work...)
{fyi, the earth rod will make no difference / will do you no good in antenna system performance}
Quote:
Originally Posted by goboatingnow View Post
I’m hoping to test my icon 7000 AT140 setup on land before bringing it all to the boat ( which is a long way away )

I’m using a HF whip ,

Could inset this up on land , what would I need for the counterpoise , an earth rod maybe

Thanks

Dave
The Long answer is....well, it is really long....but, here you go!!!


Dave,
Much of the answers you seek are in the stickies above....but there is a lot there, so it gets difficult to read through all of it....so, here's the details....


1) Unless you have a large area, and an almost unlimited budget for a vertical antenna {an acre or two of land, with the antenna in the center, with ~ 120 copper radials, of approx 100'+ in length...and thousands of dollars/pounds/euros to spend}, you will never come close to having an antenna ground for your vertical on land, that is as good as the sea water that holds your boat....
AND...
And, unless you are right on the shore (literally within a few feet/meters of the ocean water), and/or installing the antenna in a large (few square miles) of a salt water marsh / estuary, you will never have the same far field radiation pattern as you do over the sea water....{the pseudo-Brewster angle (angle below which your antenna's radiation falls over rapidly and then disappears) at 14mhz, over sea water is approx 0.8degrees (yes 4/5 of one degree)....and on land, over "average" to "very good" soil conductivity, it is 14.5 degrees....}


Those are hard facts, they are part of mother nature....and nobody can do anything about them....BUT...

But, that doesn't mean that the antenna won't work....to the contrary, it WILL work....and it will work, without any "ground" / "counterpoise" at all....it is just a matter of degree....



But, that doesn't really answer your question, does it?



2) An earthing rod (that's a "ground rod" in American English), is all but useless for an antenna ground/counterpoise.....and, except for the structure that might hold up the whip, is a waste of time / effort and money....

Although having an earth rod for lightning protection, is normal in most areas of the world, and is usually required (by building code / law) in many cities/towns in the USA, it will do nothing for your antenna performance.




3) If you have the space to lay-out a few radial wires, on the ground, around the antenna....connect these to the "grd" terminal on the AT-140 tuner....their length is NOT important, but their quantity is....i.e. the more the better.....assuming that most of them are at least 15' - 16' [4m] long, more short radials is ALWAYS better than fewer long (> 40' - 50') The same amount of copper is best used as more/shorter radials than fewer/longer ones...

a) A commonly accepted "minimally adequate" ground radial system is 16 (sixteen) radials of approx 30' in length (if you have the space), or their length should be at least as long as the antenna is high....



b) A commonly accepted "adequate" ground radial system is 32 (thirty-two) radials of at least 35' - 40' in length...

c) A commonly accepted very good (to excellent) radial system is 60 radials or more, of approx. 0.4-wavelengths (at your lowest operating frequency)

d) The commonly accepted standard (meets US FCC regs for MW braodcast stations) is 120 radials, of 0.6-wavelengths (at your lowest operating freq)....plus a copper grounding surface (usually copper flashing or screen) immediately under and surrounding the antenna base, extending out approx 0.05 wavelengths from the base of the antenna....(and fyi, even this is not nearly as good as the sea water, our boat's float in....)
BUT...




4) But, none of the above is needed, if you can arrange to mount the base of the vertical antenna (in this case the AT-140, as well) elevated above the earth (usually 8' - 15', or 3 - 5m, high, is fine), AND suspend just a few radial wires from this mounting location....

You'd need two to four radials of 1/4-wavelength on each of the bands you desire to use.....that would be a length (in feet) of approx 234 divided by the freq of the center of your operating band....and two to four radials of that length, for each band that you desire to use (2.2mhz, 4.1mhz, 6.2mhz, 8.2mhz, 12.35mhz, 16.5mhz, etc. etc.)

If you can suspend just 2 - 4 (two to four) radials PER BAND OF OPERATION, connected to the AT-140's "grd" terminal, and keeping them above the ground / not ever touching the earth, with 2 (two) radials per band, you're in as good of a position as you would be in #3a above (and, with 4 radials per band, you're as good or better than #3b, above)....

Depending on which, and how many, bands....this can be a rather easy-peasy system to set-up....

FYI, you can "cheat" a little, if this is a temporary test set-up, and/or just for you to learn from, you can get the system to work pretty well, with just a few pieces of wire....two radials tuned for 2.1mhz, can also be useful for 6.3mhz (3rd harmonic), and two to four radials tuned for 4.1mhz (4.125mhz) can be useful for 12.375mhz (3rd harmonic)....and add four radials for 8.2mhz - 8.3mhz, and you're going to have a fairly decent elevated / tuned radial system...

So....two elevated and tuned radials for 2.1mhz, and four for 4.125mhz, and four for 8.2mhz....just ten radials in all....gives you a good counterpoise for 2mhz thru 12.5mhz maritime bands, and also decent on 18mhz and 25mhz maritime bands, and even pretty good counterpoise for all bands above 12mhz, cuz there is now a decent amount of wire, even un-tuned.....and an adequate / useful counterpoise for 160m, 80, 40m, 30m, 20m, and 17m, 12m, 10m, and like on the upper maritime bands, just about all the ham bands above 14mhz...

That's 10 pieces of wire...two that are 111.4' long, four that are 56.7' long, and four that are 28.5' long....as long as they are all suspended above the ground, you're good to go....
(start with them at at least 8' high, and either run them straight out ending at approx the same height, or you can slope them down slightly, but you should keep them to a mild slope, using a decent amount of rope at the ends, so that the ends of these radials are still at least a few feet off the ground....understand it is the ground losses and the coupling of these wires to the ground, that causes the poorer performance....meaning the higher up the better....)
BUT...



5) But, while #4 above is okay....and answers your questions....I'd actually recommend something that will work better for you (better performance) AND probably be easier to install (certainly MUCH less critical, no accurate measurements needed):

This is a simple horizontal loop, fed with the AT-140 tuner (one end of the loop to the "antenna" terminal and the other end to the "grd" terminal)....suspended in the air at least 20' - 25' above the ground (40' - 60' high would be great, but 30' high is good!)....

And, this loop should be approx one-wavelength long at your lowest freq....but...but in practice, this can be 0.75 to 0.8 waves long, and still work just as good....and, since 2mhz maritime is little used over here on this side of the Atlantic, we just assume that 4mhz is our lowest band....but, if you need to use this on 2mhz, use 350' circumference as the minimum, otherwise use 240' as minimum...in any shape you can practically install 25' - 35' high....(if square that's only 60' per side)

For a LOT more detail on this, please see my posting regarding simple (cheap) land-based HF transmit / receive antennas....especially geared towards someone desiring to learn / test HF maritime comms...

Post #12 here:
Re: Landlocked with chance to learn ham on icom 706
https://www.cruisersforum.com/forums/f13/landlocked-with-chance-to-learn-ham-on-icom-706-a-221856.html#post2960916




And, posts #25 and #26, here:
Re: HF shore station
https://www.cruisersforum.com/forums/f13/hf-shore-station-145350-2.html#post1816068




And, when looking at the stickies, be sure to see post #57 here (which is duplicate post to one of the above), where I try to keep the stickies updated with pertinent reference info...
Re: HF-SSB Radio, Proper Installation Tips/Techniques, etc.
https://www.cruisersforum.com/forums/f13/hf-ssb-radio-proper-installation-tips-techniques-etc-198305-4.html#post2961064




I hope this helps.

fair winds

John
__________________
John, KA4WJA
s/v Annie Laurie, WDB6927
MMSI# 366933110
ka4wja is offline   Reply With Quote
Old 02-12-2020, 00:09   #3
Nearly an old salt
 
goboatingnow's Avatar

Join Date: Jun 2009
Posts: 14,368
Images: 3
Re: Testing my boats HF on land

John , huge thanks , lots to digest , again thanks for all the work on that post

Dave
__________________
Interested in smart boat technology, networking and all things tech
goboatingnow is offline   Reply With Quote
Old 02-12-2020, 09:21   #4
Registered User
 
ka4wja's Avatar

Join Date: May 2007
Location: Florida
Boat: Catalina 470
Posts: 2,477
Re: Testing my boats HF on land

Dave,
You're very welcome!
Quote:
Originally Posted by goboatingnow View Post
John , huge thanks , lots to digest , again thanks for all the work on that post

Dave
Unfortunately, since this was a query regarding an antenna for testing purposes, I didn't delve into other things....which I probably should have?
So, here is one very important point to always remember:


The single most important measure of HF communications success is receiver signal-to-noise ratio (s/n)
And, since we cannot do much about the other stations' transmit power nor their antenna efficiency, what we should concentrate on is reducing the noise that we receive!

For most HF users these days, their receive s/n is limited by their local man-made RF noise (RFI).....although, in some situations improving our antenna's / antenna system's ability to reject natural / atmospheric noise, can be of great help in improving our receive s/n!!

Although on our boats, there is no possibility of doing the latter...as this would require multiple antennas, spaced out, controllable directivity, adjustable phasing, etc....but, we can do something about the former (reducing our local RFI), and as these days is it the predominant factor in controlling our receive s/n, it is THE most important thing we can do to improve our HF comms success....

...a close second place is, a good understanding of radiowave propagation and antenna system design, choosing the proper antenna and freq for our desired communications path and time-of-day, etc....but, this takes time, study, training, experience, etc....and with the SOLAS conventions attempting to do two things simultaneously: add redundancy to Distress signaling; and reduce / eliminate the need for trained radio engineers on-board; we ended up with DSC, both VHF-DSC and MF/HF-DSC (and 406mhz EPIRB's, and INMARSAT-C, and now newly GMDSS-certified satcom terminals from Iridium and INMARSAT), under the GMDSS....all of these are supposed to eliminate the need for "trained" radio ops / radio engineers on-board.....and when you combine that, with the fact that we (many of us, both on our small pleasure boats, and on large commercial ships) have brought on-board a good deal or RFI-producing devices/products, we end up with poor performing HF comm systems, and nobody on-board that knows why, nor how to fix it!!!!

Fyi, an absolutely true story from right here on Cruiser's Forum....a few years ago, in a discussion on my success in still receiving the BBC on shortwave (from their broadcasts beamed at Africa), after they stopped beaming any programing to the Americas....a gentleman on a large commercial vessel, posted here that he and his partner have tried to use their vessel's GMDSS console's HF radios (full Furuno Sea Area A1, A2, A3, and A4 GMDSS Console) to receive the BBC broadcasts, and while in the Gulf of Mexico and when transiting along the US east coast, they were unable to hear anything on any of the freqs / times I wrote about....all they hear is lots of noise, buzzing, static....he later sent me a message that "sometimes" they can hear the USCG SSB Voice broadcasts "barely" above the noise....(fyi, these are strong signals, from 4000 watt transmitters, beamed across the water, frome New Orleans and Chesapeake, Virginia....and I receive them like they were right next door)....
The fact that he was reporting was that they had so much on-board RFI that their HF comm system was all but useless.....it transmitted just fine, and their weekly MF/HF-DSC tests all checked out (assume they made DSC
Test calls), but they had never been able to use HF Voice....

He was a mate, standing a bridge watch, and his partner was his boss (not sure of his ranking)....and, he was surprised that the radios were installed and never tested, as was I!!!
But, to be clear, I assume they were tested when installed....but nobody had actually tested them properly for the annual inspection, after the original installation?? Another example of half-assed jobs, done by poorly trained people....someone, a "GMDSS-certified installer" (which just means they spent a few hours memorizing answers to published questions, and passed a simple test), goes on-board, presses a few buttons, gets a received acknowledgement, writes notes down in the log, signs their name, and leaves...having made $1000....and, the paperwork says all is good, the USCG is happy (they are wicked strict over here, for US=flagged commercial vessel!!), the skipper is happy, the vessel's owners are happy....but, nobody actually proved that the system is really working!!!

My point with all the above:
Most users of HF comms (and God forgive me for writing this, but most electrical engineers, and even most commercially-licensed radio techs / engineers), are ignorant of what all the made-in-China consumer crap (especially all those cheap "wall-warts" / cheap switch-mode-power-supplies) have done to the HF spectrum....I asked a USCG officer, who was TEACHING a commercial GMDSS class, about RFI, and he actually had NO idea what I was talking about....true story....(and, I'm not sure if they teach about RFI at maritime academies? but, for those looking to obtain an engineering rating, they should be ashamed if they don't)


I know, I know....all the above probably sounds like I crying "the sky is falling".....but that's not it....
What I am trying to shout is: Understand what RFI does (reduces our success in HF comms), and where it comes from (it can come from any electrical / electronic device, please read the stickies above for details....but, get rid of all the wall-warts, AC mains-powered phone chargers, etc. etc. etc....or at least get them far away from your HF antennas!!)



Btw, while I DO practice what I preach (I don't have any RFI-producing crap on-board, except for the weak "bleeps" from my refrigeration unit, that don't cause much issue), just one week ago I found something here on-shore that screwed up my HF receiving on-shore....and, yep it was a new phone charger!!!! Argh!!
My old one wasn't a problem, but the new one raised my noise level on 75m (3.6mhz) by about 10db....not catastrophic, but unacceptable to me....so, I tossed the darn thing in the back of a drawer on-shore and an back to using my old phone charger!!
So, even someone as anal about RFI as I am, can find themselves being lazy about it....
Moral of all of this: The falsely-certified or self-certified made-in-China consumer crap that "everyone" seems to demand be made even cheaper, is seriously effecting our radio spectrum!
And, finally, if you want more proof, have a look at COSPAS-SARSAT, as well as INMARSAT and Iridium, all of whom have registered seriously increased terrestrial noise (coming from our cheap consumer crap) that effect their ground-to-space link budgets!!! They are working on attempts to at least get the EU to actually enforce real/actual testing of devices shipped into the EU, but alas "money talks" and the consumer economy is trumping safety (guess they don't remember what SOLAS stands for?) ....as for the US, there are some at the FCC that have tried, but here again money talks....so, we are now getting the same crap imported!!
Sad state of affairs....those that cry out about air pollution, water pollution, land fills being over flowing, etc. etc....all still want their cheap consumer crap, and have no concern about pollution of the airwaves! Truly ignorant? Maybe, but in my opinion they're mostly arrogant!!






Whew....sorry about going off on a rant here....guess I was extra motivated this morning....

Hope this helps

John
__________________
John, KA4WJA
s/v Annie Laurie, WDB6927
MMSI# 366933110
ka4wja is offline   Reply With Quote
Old 02-12-2020, 17:22   #5
Registered User
 
Jammer's Avatar

Join Date: Jan 2010
Posts: 1,907
Re: Testing my boats HF on land

I note that while John is (by his own admission) perhaps off on a rant, he is also absolutely correct on the facts of RFI.


HF comms require an electrically quiet environment, no two ways about it.
__________________
Never ascribe to wisdom that which is adequately explained by good luck.
Jammer is offline   Reply With Quote
Old 02-12-2020, 20:38   #6
Moderator
 
Jim Cate's Avatar

Join Date: May 2008
Location: cruising SW Pacific
Boat: Jon Sayer 1-off 46 ft fract rig sloop strip plank in W Red Cedar
Posts: 17,389
Re: Testing my boats HF on land

Quote:
(I don't have any RFI-producing crap on-board, except for the weak "bleeps" from my refrigeration unit, that don't cause much issue)
John, here I imagine you are talking about a Danfoss based reefer, no?

If so, have you done anything to minimize the RFI from the controller? I find those "weak bleeps" to be very annoying, and our Danfoss is so old that it doesn't have the noisy unit. I get that RFI from boats moored 50 or more meters from us. And non-ham friends have asked me how to minimize the interference on their boats and I have not come up with any useful ideas. The usual combination of ferrites plus bypass caps has had little effect for the ones who have tried them.

Any ideas?

Jim
__________________
Jim and Ann s/v Insatiable II, back in Port Cygnet after adventures in the big smoke.
Jim Cate is online now   Reply With Quote
Old 02-12-2020, 21:01   #7
Registered User
 
ka4wja's Avatar

Join Date: May 2007
Location: Florida
Boat: Catalina 470
Posts: 2,477
Re: Testing my boats HF on land

Jammer, et al,

I hope you don't mind a nit-pik, here? 'Cuz, I do understand your point, but just the way you write it, it's a bit misleading.

HF comms actually does not require an "electrically quiet" environment at all, but rather is easier in an "HF quiet" environment...

Or more accurately, high s/n HF reception is easier achieved in a "quiet HF environment"! And, these days, with the plethora of RFI-producing devices surrounding us, it's difficult to find a "quiet HF environment" in suburbs, etc., let alone in cities and urban areas...

(successfully HF comms take place all the time in heavy / high electrical environs....a very good friend of mine, and fellow ham, has his house and 120' tower, just 100 yards from high-voltage transmission lines, and he works the world just fine....myself, I have the end of one of my antennas at home onshore, within 40' of 28,000 (?) volt power lines....and most users of HF ham radio, etc. have a great deal of electrical devices, air cond, heat, refrigeration, TV, satellite, lights, etc. etc. etc, within dozens of feet of their HF antennas....so electrically quiet locale is absolutely unnecessary....what is important is the HF RFI radiated by the tons of consumer crap and their chargers/power supplies, that have populated our lives, and the distance our antennas are from those devices and their wiring...)



As an example....FYI, the old AT&T Hi-Seas station, WOM, in Ft. Lauderdale/Miami (although in the 1930's and 40's, was originally in Ojus, FL, between N. Miami and Hallandale), since 1948 and up until their closing in 1999, had their receive site at 1340 NW 40th Ave, Ft. Lauderdale (where I personally toured their system decades ago)....{the transmit site was moved to Krome Ave, in Pennsuco, FL (West Miami) at the same time....and I also toured the transmit site....and, unlike the receive site, it was certainly way out in-the-sticks...}

Now, certainly in the 1950's their rec site locale was not in the middle of a big city, and some of the cross streets off of US Hwy 441 (NW 40th Ave) were dirt roads back then....but NW 40th Ave (US Hwy 441) was a major North-South road / highway and, in addition to "powerline road" just a half-mile to the east, was a major route for electric powerlines....

Ft. Lauderdale grew rapidly in the 60's and 70's (and 80's and 90's), and the Lauderhill Mall was opened in 1966, right across the street from WOM, housed in the bunker-style AT&T building (with its large LPDA arrays on the rood, and its medium towers and wire receiving arrays in the yard out back).....WOM's receive site occupied most of one floor, and the big antennas on the roof and out in the backyard, the whole complex was rather modest, with the building, parking lot, and "antenna farm" only taking up about 9 - 10 acres....the building (and towers) is now gone, but using Google Earth and/or Google Maps satellite view, you can still see the outline of the wiring / cable paths for some of their antennas...


{the transmit site, out in west Miami, was MUCH bigger....more than a dozen antennas spanning dozens and dozens of acres (I think they owned 200 acres)....and > a dozen Harris 740-M (10kw) transmitters....wicked cool!}

FYI, the Lauderhill Mall, when it opened in 1966, was the first all-indoor / air-conditioned Mall in the whole SE United States!!!
I still remember the radio jingle / song they used to advertise shopping there: "the wonderful world of air conditioned shopping, Lauderhill Mall, Lauderhill Mall!"
Think they had a big power substation there, to run all that air-conditioning....talk about a high electrical locale!

With the expanse of "suburban" sprawl, by the mid-to-late 1960's, WOM was quickly surrounded by suburban housing, condos, shopping centers, businesses of all sorts, and even some light industry, etc....and they continued to operate just fine....all the way until AT&T shut them down in 1999 (few customers with hi-seas phone calls at $5/min, so after FCC paused their shut-down for 7 months, they were finally shut down Oct 9, 1999)

The reason I mention WOM here, is to show the point that HF comms are not only done in electrically noisey environs everyday, but how much has changed in the past 20 years in terms of urban, suburban HF RFI / radio noise (which can raise noise levels even from miles away), and it is this HF noise / RF noise / RFI that is the issue....
When you have lots of cheap, un-certified (or usually falsely / fake certified) square-wave smps's running, and each one has some wiring attached to them (and they are NOT supposed to radiate far, as the part 15 cert, which is typically falsified, shows)....you have lots of interfering devices, with wires attached acting as their radiating antennas....and when you have 1000's of these things within a few hundred feet of your antennas, you have an "HF noisy environment", and high rec s/n HF comms become more difficult...

That's what I was writing about...




So, there you go.....just a clarification for all....hope it helps.


fair winds.

John
__________________
John, KA4WJA
s/v Annie Laurie, WDB6927
MMSI# 366933110
ka4wja is offline   Reply With Quote
Old 02-12-2020, 21:39   #8
Registered User
 
ka4wja's Avatar

Join Date: May 2007
Location: Florida
Boat: Catalina 470
Posts: 2,477
Re: Testing my boats HF on land

Jim,
Yep....that's what I'm referring to...
I have a older Adler Barbour CU-100 Cold Machine....which is a Danfoss BD-50 system...

And, mine also being older (actually the "guts" are original from 1999, and I put in a newer connection panel in 2010, I think?), I too have only some minor "bleeps" (sounds like a weak, raspy, random CW transmitter)....and luckily they've only once, for about 30 minutes, have they ever been an issue (and I shut off the frig/freezer, for a half-hour)....that was in 2007/2008, when HF signals on 14mhz weren't that great....

But, like you, I also hear other boats fridges!

Not sure which boats, and how far away, but in anchorage in Bahamas a couple years ago, I heard at least 3 other boats' fridges, much stronger/louder than mine...and, every boat there was newer than mine...

And, a neighbor pulled in a decent-sized yacht last year, for a couple months, and everyday when I was on-board at the dock I heard his fridge louder than mine, as well....and his boat was exactly 60 yards away...

FYI, my AB Cold Machine / Danfoss BD-50 compressor is in the port-side lazarette, just below my port backstay....my Icom AT-140 tuner (and its GTO-15 wire) is in starboard-side lazarette, just below my starboard backstay (which is my main HF antenna)....
The total distance between the BD-50 compressor controller (the thing that makes the RFI) and my AT-140 is about 9' - 10'....and that's as far away as I can get 'em...

So...my common-sense conclusion is that the newer units produce more RFI...
Not sure I'm correct here, so don't take that as written in stone!

Now, about 10 years ago, when replacing the Adler Barbour wiring connector panel, I inquired to the Adler Barbour / Dometic rep about the RFI, I was told that they actually have a solution!!!
He said they have an RF shielded and RF-bypassed compressor power supply / controller, which produces "no noticeable RFI"!!
{he explained that the Danfoss compressors run on low-voltage 3-phase AC, so it's the compressor power-supply/controller that makes most of the RFI}
I said, "Wow!"
And I asked if he could order one for me....then he told me the price...
$745.00 !! (yep, that's seven hundred and forty-five dollars!)
So...
So, I just live with the minor "bleeps"!

Now, I suppose if it was worse than just some minor "bleeps", I'd spend some time trying to figure out a RF shield, and some bypass caps on all the wiring leaving the compressor power supply / controller, and install all new shielded power and thermostat/control wiring, and run a few turns of all that new wiring thru some ferrite torroids (not just beads, 'cuz every turn/wind thru increases choking impedance exponentially)
But...
But since I don't have anything but minor "bleeps", I never did any of that...although, you're more than welcome to go-for-it and report back...
(btw, I figured the biggest hassle for me, after replacing all the wiring, was going to be working in the lazarette, trying to design/form an RF shield....and I didn't want to spend $750 bucks and take the lazy way out...so, I live with the bleeps)


Quote:
Originally Posted by Jim Cate View Post
John, here I imagine you are talking about a Danfoss based reefer, no?
Yep...

If so, have you done anything to minimize the RFI from the controller?
No, see details above...

I find those "weak bleeps" to be very annoying, and our Danfoss is so old that it doesn't have the noisy unit. I get that RFI from boats moored 50 or more meters from us. And non-ham friends have asked me how to minimize the interference on their boats and I have not come up with any useful ideas. The usual combination of ferrites plus bypass caps has had little effect for the ones who have tried them.
Yep, the compressor and its power supply/controller has got to be shielded first....no way around that...
And, I suspect (educated assumption) that you'd need to use some shielded power and control/thermostat wire as well, and run this a few turns thru some ferrite torroids, not just clamp-on beads...
Ferrite beads don't have enough "umph" (that's a technical abbreviation of choking impedance, btw)....you'd likely need a few turns of shielded wire thru some ferrite torroids..

Any ideas?
See all above...

Jim
Jim, bottom line...if you have the $750 bucks to spend, there is a solution....but you still may need to change some wiring, depending on where the wiring is run in respect to your HF antenna...

Everything I know about Danfoss RFI, is written here....
Wish I had more.

fair winds

John
__________________
John, KA4WJA
s/v Annie Laurie, WDB6927
MMSI# 366933110
ka4wja is offline   Reply With Quote
Old 02-12-2020, 23:38   #9
Registered User

Join Date: Aug 2012
Posts: 1,062
Re: Testing my boats HF on land

Here is the Table of Contents for a series of articles on ham radio written by a man who knows well the subject.

https://thesilicongraybeard.blogspot...io-series.html
Richard5 is offline   Reply With Quote
Old 03-12-2020, 01:43   #10
Moderator
 
Jim Cate's Avatar

Join Date: May 2008
Location: cruising SW Pacific
Boat: Jon Sayer 1-off 46 ft fract rig sloop strip plank in W Red Cedar
Posts: 17,389
Re: Testing my boats HF on land

Quote:
Jim, bottom line...if you have the $750 bucks to spend, there is a solution....but you still may need to change some wiring, depending on where the wiring is run in respect to your HF antenna...
John, I don't have a problem with my antique Danfoss compressor, because it predates the microprocessor controller that causes the problem. It is for other folks noisy installations that I was enquiring.And I doubt if many would be interested in the $$ solution, just like you!

But thanks for the ideas... much what I'd thought tried in part.

73 de Jim
__________________
Jim and Ann s/v Insatiable II, back in Port Cygnet after adventures in the big smoke.
Jim Cate is online now   Reply With Quote
Old 08-12-2020, 08:41   #11
Registered User

Join Date: Apr 2011
Location: Northport, Michigan
Boat: Trailerable cruising boat
Posts: 559
Re: Testing my boats HF on land

Since this thread is filled with long and rather tangential replies, I will comment on one of those tangential topics: the infringement of urban development on antenna sites originally constructed in areas of low habitation:

To give this some relationship to cruising, in 2018 we cruised the Galapagos Islands aboard M/V ERIC, an 85-footer, and not my yacht, but a small eco-tour cruise ship. (Visiting the Galapagos in your own yacht is somewhat difficult, but I stray from my topic.) To reach the island we flew from Ecuador. On our return flight we visited Quito, and had a two night layover.

I was very excited to visit Quito because it was the home of station HCJB, a rather famous HF broadcast station. An engineer at HCJB was Clarence Moore, who invented the quad loop antenna for use there and which was later used as the driven element for the cubical-quad antenna. (The high altitude of Quito was causing problems with corona discharge from the ends of antenna elements operating at very high power levels.) I was hoping to visit HCJB and see their antenna farm. Alas, it was not to be.

Quito had recently built a new airport--the one we landed at--located about 20-miles north of the city on a hilltop flattened to make the airport and at about 9,000-feet elevation. The HCJB antenna farm was located nearby and was in the flight path for the airport, necessitating the removal of all the HCJB towers and antennas, and the end of one of the most famous HF Broadcast stations.
continuouswave is offline   Reply With Quote
Old 08-12-2020, 08:58   #12
Registered User

Join Date: Apr 2011
Location: Northport, Michigan
Boat: Trailerable cruising boat
Posts: 559
Re: Testing my boats HF on land

Quote:
Originally Posted by Richard5 View Post
Here is the Table of Contents for a series of articles on ham radio written by a man who knows well the subject...[/url]
The American Radio Relay League has been publishing very highly regarded books on the topic of amateur radio antennas for many years. I have generally found that a well-writted, nicely illustrated, carefully edited book on a particular topic is generally a very good source of information. For advice on HF antennas, one might consider:

ARRL Antenna Book

The book in now in its 24th edition and is published in four volumes.

Another great source of information--available now at no cost and online as a PDF file--is the seminal text

RADIO ENGINEER'S HANDBOOK
by Frederick Terman
Professor and Dean, School of Engineering,
Leland Stanford University
Published by McGraw-Hill

https://electrooptical.net/OldBooks/...dbook_1943.pdf

See Chapter 11, ANTENNAS
continuouswave is offline   Reply With Quote
Old 08-12-2020, 16:24   #13
Registered User
 
Brian.D's Avatar

Join Date: Jan 2019
Location: Oceanside Ca
Boat: Lancer 27PS
Posts: 391
Re: Testing my boats HF on land

Fact: a 35 foot wire antenna strung between my eave and a tree, with a gaggle of several lengths of wire thrown on the patio cover, produced usable signals in Europe on the 14MHz band, and multiple WinLink connections from south-west on 14MHz and west coast on 3.5MHz and 7MHz.

If you want to drop a single wire from your tuner ground lug, make it a quarter wave length of the frequency you want to test. Say 14.3MHz ... 234/14.3=16.4 feet of wire. This should also tune one-eighth wave as well, or 8.9MHz.

JMHO
__________________
Brian D
KF6BL
S/V Takara
Brian.D is offline   Reply With Quote
Old 09-12-2020, 02:16   #14
Nearly an old salt
 
goboatingnow's Avatar

Join Date: Jun 2009
Posts: 14,368
Images: 3
Re: Testing my boats HF on land

Thanks. Once the temps here get back over freezing , I値l get cracking
__________________
Interested in smart boat technology, networking and all things tech
goboatingnow is offline   Reply With Quote
Reply

Tags
boat

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Outstanding Boats - A Special Selection of Unusual and Noteworthy Boats I Find Steadman Uhlich Monohull Sailboats 232 10-11-2019 12:47
Production Boats vs Custom Boats seaturkey Monohull Sailboats 64 07-01-2015 08:23
Power Boats/sail boats Seagull111 Our Community 17 06-08-2013 10:16
Counting Down to the Sale of our Land Locked Home - Looking for Advice on Boats Vajake Powered Boats 4 04-07-2011 15:31
Load Testing and Conductance Testing Joe500 Electrical: Batteries, Generators & Solar 0 02-12-2009 16:12

Advertise Here


All times are GMT -7. The time now is 16:27.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2021, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2021, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.