Issue with Icom M802 Installation

[TLSparks]

Recommend you use FSK mode as CW does not normally put out any power and FSK applies a 100% modulation level tone.

Originally Posted by mcerdos

Hi Guys,

Thank you for the support and help. I am heading out to the boat this week with a multi-step plan.

Step 1 - Using the Bird meter (and radio in cw mode) check the cable for forward power and reverse power while AT140 is connected.

Disconnect the AT140 and place a dummy load on the end of the RC8X cable at the AT140 end and check forward power and reverse power. This should tell me if the current cable is bad. If the cable is good and the readings are within spec, at least I can eliminate everything pre AT140.

Step 2 – (Probably) replace RG8Xcable anyway with a length of RG213 and check to see if RFI is lower. Prior to changing the cable, run the cable over the deck and check to see if RFI is gone. If RFI is still present, this will be confirmation I am getting it post AT140. Please note here – I am somewhat forced to run the cable through the same conduit as other cables as this passes through two watertight bulkheads. Running the cable outside of the conduit will require an awful lot of work. This can be done, but only as a last resort.

Step 3 – Replace wire connecting AT140 to antenna with high voltage wire and ensure crimps are secure and watertight.

Step 4 – Connect AT140 to manufacturer installed counterpoise using pure copper strip (not wire). I have ruled out the KISS grounding system option.

Again check for RFI

Step 5 – install ferrites with at least 2 wraps on all cabling running through the conduit AND on all cabling near the antenna.

If this all works and I have no RFI, I will know my basic installation is good. I will pull the cable back through the conduit. If I am still getting RFI while in the conduit, I know at that point I will have to run the cable through a separate channel. Like I said, this is a last resort.

I haven’t decided yet on a line isolator. I have one from my HAM friend to try out.

More to come soon.

Thanks for all the ideas and thoughts.

[mcerdos]

Originally Posted by TLSparks

Recommend you use FSK mode as CW does not normally put out any power and FSK applies a 100% modulation level tone.

Thanks - will do.

[SoonerSailor]

You can use CW with a key connected to the proper lines on the accessory jack, but like TLSparks says, to get a steady output by keying the mic you want to be in FSK mode.

Sounds like you have a very good plan.
Let us know your findings.

Chip

[ka4wja]

Wishing you good luck!!

See factual tips/details in red...and some opinion in blue...


~~~~~~~~
EDIT....

PLEASE understand that I mean NO offense to anyone at all!!!
EVERYONE is entitled to their opinions, etc....
But, I feel I'd be remiss if I didn't try to clarify things here a bit...

I see I'm in the minority here, as I highlight some of what I believe is wrong with your plan....
But, I stand firmly and confidently with the facts that I wrote here, as well as my opinion here in blue!!!

You cannot see RFI on a watt meter....(and I wonder if you are getting swept too far a field from the primary issue here, eliminating your on-board transmit RFI...)

And while this part is my opinion, it is based on my 40 years experience with all of this, my 30 years in the electronics / communications industry, my majoring in physics, etc. etc. etc....and everyone else with years of experience in these matters....
You should not start your testing without first finishing the installation, by using a line isolator and known-good coax/connections....


End of EDIT...
~~~~~~~

Originally Posted by mcerdos

You never addressed exactly how you are connecting to this "bronze plate" on the rudder.....what I mean is: How is this "bronze plate" connected to your copper strapping???
As I've never seen a rudder mounted plate actually working well, so this may be the crux of the problem....but, we should be able to find a work-around using proper installation procedures (including a line isolator and known-good cable/connectors)...


Step 1 - Using the Bird meter (and radio in cw mode) check the cable for forward power and reverse power while AT140 is connected.
Unless you have a CW / Morse key plugged into the ACC jack (pins #1 and #2) and use this to key the transmitter in CW mode, you'll not get any output in CW mode.
So, the easiest way to generate a steady carrier is to use FSK Mode and simply push the microphone PTT button.


Disconnect the AT140 and place a dummy load on the end of the RC8X cable at the AT140 end and check forward power and reverse power. This should tell me if the current cable is bad. If the cable is good and the readings are within spec, at least I can eliminate everything pre AT140.
This really doesn't tell you whether the cable is "bad"....just that it "may be bad"....

Understand that while use of a power meter, Bird or otherwise, (and by measuring the fwd and rev power, you calculate the VSWR), will allow you to check the LOSS of the cable and the ability of the AT-140 to provide a good VSWR to the transceiver.....but, please take note of these VERY important things:
a) the loss in 25' of even mediocre quality RG-8x cable on HF freqs is negligible....(0.5db at 30mhz....or approx. 10% loss)


b) NO power meter will show you poor shielding of the coaxial cable, for that you'd need a an RF current pick up loop set at a specific distance from the cable and usually a calibrated spec analyzer and/or a precision RF micro-power meter.....
But, whatever the case may be.....
In regards RF shielding, most RG-8x cable is crap compared to even budget-buy RG-213...

Further you cannot see RF flowing on the outside of the coax (or other cables), known as "common mode" currents with any standard power meter...
You'd need a coil around the outside of the cable connected to a precision RF micro-power meter or calibrated spec analyzer...
But, whatever the case....
It's easiest to just eliminate common mode issues altogether by using a "line isolator" AT the tuner end of the coax and ferrites on all control/power wires...

(Actually doing these tests on-board, would be a waste of time, as if you suspect the cable....just replace it with a better/known good cable...and if you suspect common mode issues, you have RFI, etc. just install a "line isolator" and "ferrites")


c) the M-802's power meter (LCD Bar Graph) does a good job of showing your forward power output and since the M-802 will fold-back power gradually when subjected to higher than acceptable SWR (starting at an SWR of approx. 2:1), so if you have full deflection (all 8 segments) show on hi-power transmit (in FSK mode), then you know that the AT-140 IS working and providing the M-802 with a decent VSWR...

So, while I think ALL HF radio installations should have an external pwr/swr meter permanently installed, you CAN use the metering in the M-802 to verify the radio's power output AND check that the SWR is below 2:1...



Step 2 – (Probably) replace RG8Xcable anyway with a length of RG213 and check to see if RFI is lower. Prior to changing the cable, run the cable over the deck and check to see if RFI is gone.
I'm not going to say that this will not work...but you may be wasting your time here...
On-board transmit RFI is a weird bugger!!!
The ONLY REAL way to test for it is to try your ACTUAL FINAL INSTALLATION....NOT running wires along the deck, in a temporary location, etc...
You may get lucky and find things work fine with the cables along the deck and then still work well in the final installation configuration....BUT...
BUT, I would NEVER recommend that you do this, as it is a pretty big waste of time/effort, since what you need to do is test/evaluate and reduce/eliminate on-board transmit RFI WITH YOUR FINAL PERMANENT INSTALLATION, and unless you check that, you may spend hours and hours chasing your tail, when checking the final end product installation you may find that it works great!!!

BTW, I'm basing ALL of my recommends and tests on the simple basic installation procedures which INCLUDE the installation of a "line isolator"....
If you're going to try to do this without one installed AT the tuner end of the coax, you may be in for a lengthy and frustrating time...


If RFI is still present, this will be confirmation I am getting it post AT140. Please note here – I am somewhat forced to run the cable through the same conduit as other cables as this passes through two watertight bulkheads. Running the cable outside of the conduit will require an awful lot of work. This can be done, but only as a last resort.
Understand that the "cable" might be okay, but the connectors/connections may be the primary issue with "the cable"....
So, just replacing the whole cable/connectors with a known-good (pre-made and guaranteed) RG-213 and connectors is a good idea....
BUT...
But, trying to eliminate on-board transmit RFI without first installing a "line isolator" is going to be an exercise in futility!!!

In my opinion, trying to track down / eliminate on-board RFI without first installing a "line isolator" is a waste of time and effort...
Spend the $50 - $80 on a "line isolator", it will not be wasted....

So, step #1 should be installing a "line isolator" AND replacing the coax with a known-good length of cable (preferably RG-213) with professionally installed and guaranteed connectors...
And then check your installation for RFI and power/swr, etc..
(In my opinion, the installation is not actually finished without the line isolator and know-good cabling/connectors...)




Step 3 – Replace wire connecting AT140 to antenna with high voltage wire and ensure crimps are secure and watertight.
Yes, GTO-15 wire is always the best procedure here...
(I was NOT aware that you did not have GTO-15 wire here already...)



Step 4 – Connect AT140 to manufacturer installed counterpoise using pure copper strip (not wire). I have ruled out the KISS grounding system option.

Again check for RFI
This sounds good...
FYI, if you use a "Scotch-Brite" pad, you can quickly clean/polish the copper strapping.....if it's shinny, it's good!!




Step 5 – install ferrites with at least 2 wraps on all cabling running through the conduit AND on all cabling near the antenna.
Use of a "line isolator" on the coax (AT the tuner end) IS part of normal/standard installation procedures....use of ferrites on control/power wires and on other wiring is usually done, but many times optional...

(note that even a cheap line isolator provides a few thousand ohms of common-mode "choking" vs. a couple hundred from a couple ferrites...have a look here Common-mode chokes )

If this all works and I have no RFI, I will know my basic installation is good. I will pull the cable back through the conduit. If I am still getting RFI while in the conduit, I know at that point I will have to run the cable through a separate channel. Like I said, this is a last resort.



I haven’t decided yet on a line isolator. I have one from my HAM friend to try out.
If I may be so blunt to ask why??
Use of a "line isolator" has been common practice on-board for about 15 years now!!! (and has been well-known and used on land-based end-end/Marconi-type antennas for decades.....but was simply called an RF-Choke....)

I don't know what "line isolator" your ham friend has for you to try....but assuming it is one of the two I recommended above, it WILL NOT HARM YOUR SET-UP IN ANY WAY!!!
And, it WILL HELP!!!

Use of a "line isolator" is recommended by Sailmail, Winlink, every marine SSB radio installer/tech I've ever met, SGC, ICOM, etc...

In my 40+ years of experience in HF comms (ham and maritime) both on-board and on-shore, I've not found one thing that is more commonly accepted and less controversial than this....

But, to each their own....
I gave you the facts, included links to sites that show/explain the choking capabilities, as well as sites selling/explaining things....as well as my personal 40+ years of experience...
So, I guess I'm just curious if there is something I left out, that has you wondering whether or not a "line isolator" is good or not...


More to come soon.

Thanks for all the ideas and thoughts.

Again, fair winds and good luck!!!

John
s/v Annie Laurie

[Auspicious]

Originally Posted by mcerdos

I am using a 23' antenna, not the back stay. The antenna was mounted in a vertical position per icom instructions.

The antenna configuration has nothing to do with your issue. No matter what antenna you use--backstay, alternate backstay, whip, or anything else you are going to be in the near-field radiation pattern of the antenna. You live in an RF field while you are speaking.

Radiative coupling from the antenna shouldn't result in the symptoms you describe.

The guidance from Bill and John on cables, isolators, and ferrites is your best bet.

Originally Posted by mcerdos

I only question the use of ferrites at this point because of the large amount of RFI experienced. When I transmit on high power, I can hear my voice coming out of the VHF radio speaker that is turned off.

The ferrites will keep RF current from flowing on the outside of conductors and radiating into other conductors. Every wire on the boat can be an antenna. In the scenario you describe, something is radiating in the boat (very often the coax between radio and tuner) and getting into something else (often power conductors) and potentially reradiating or conducting to the symptom of interference (in this case your VHF speaker). The modality can be hard to pin down. Unless you are going to go hunting with a spectrum analyzer to determine whether it is power through the audio stages of your VHF, the wires to the speaker acting as an antenna and a cold solder joint acting as a detector, or IF-to-IF interference you are best off following the guidance of Bill and John.

Ferrites, particularly type-31 ferrites, are your friend. Gary Jensen at Dockside Radio has a good selection. You can also try The RF Connection or The Radio Works.

Originally Posted by ka4wja

a) Did they read and follow Sailmail's recommendations in the Sailmail Primer???
SailMail Primer

Agreed. Although Bill and John have differentiated it isn't clear to me that the message has gotten across.

First, grounds are important. You cannot just connect everything to everything and expect it to work, especially at RF. Google "single point ground" and read carefully. Really think about alternate paths. For example, many VHF antennas are 50 ohms at 150 MHz but are a DC short. Mount them to your masthead on a metal bracket and you have two paths to ground - the coax shield and the mast. That can become a ground loop that is both a source of and a potential receiver of interference.

One of the problems with the guidance to run copper tape to pushpits, tanks, and engines is that you add ground loops.

Second, grounds and counterpoises are different things with different functions. The KISS-SSB for example is a counterpoise and not a ground per se. Your Dynaplate is a ground and not a counterpoise. Sloppy vocabulary leads to poor installations and bad performance. Commercial and military installations ashore and afloat have had this sorted out for many decades but that information doesn't seem to have consistently filtered into the recreational boating community.

Originally Posted by ka4wja

But, putting them through the SAME hole/wiring chase seems like a BAD idea...and I'm with Bill on this one, why not just drill (and seal up) another hole a few feet away???

Add my vote to theirs. Drill a hole and add a cable clam. If they're good enough for a thruhull they're good enough for a watertight bulkhead. We put them in damage control and collision bulkheads on warships all the time.

Originally Posted by ka4wja

5) Scrap the RG-8x coax

Agree. Don't bother testing it. What you're testing won't measure what you care about. Really good coax is worth every penny. LMR-400 or RG-214 with good silver-teflon connectors.

Originally Posted by ka4wja

9) Oh, and while I don't recommend the "KISS" (see other threads), I'm not going to debate that here.....primarily as it has no bearing on this discussion!!

There are few things I disagree with John about but this is one. The KISS-SSB is good value for money. I think it's good value for DIY labor also. You can certainly do better but it will take a very long time and on an existing boat a huge amount of disassembly (what Janet calls "blowing up the boat"). I rarely recommend shortcuts but the KISS-SSB is one I do heartily recommend.

Originally Posted by mcerdos

Step 1 - Using the Bird meter (and radio in cw mode) check the cable for forward power and reverse power while AT140 is connected.

A plan is a good thing.

Don't bother with this. You won't find RF leakage through the shield. In fact, a measured good reverse power can easily be contributed to by poor shielding. Any power radiated forward or reverse won't show up as reflected power at the radio. Just replace the cable and connectors with good stuff.

Originally Posted by mcerdos

Step 2 – (Probably) replace RG8Xcable anyway with a length of RG213 and check to see if RFI is lower.

Start here. The idea of a temporary alternate routing is a good one.

Originally Posted by mcerdos

Step 3 – Replace wire connecting AT140 to antenna with high voltage wire and ensure crimps are secure and watertight.

I may have missed something here. What are you using now. This is a stroll down the garden path as the only reason for GTO-15 or similar high voltage wire is to reduce the potential for direct contact RF burns and has nothing to do with RFT. That said, I have never heard of an RF burn at the power levels we run.

Crimps are important. There should only be two - one at the ring terminal for the tuner and one at the ring terminal to connect to the antenna. You said you have a whip so there should be a terminal stud there. If not I will send you pictures of my recommended attachment.

Originally Posted by mcerdos

Step 4 – Connect AT140 to manufacturer installed counterpoise using pure copper strip (not wire). I have ruled out the KISS grounding system option.

Good. See above on the KISS counterpoise (not ground).

Originally Posted by mcerdos

Step 5 – install ferrites with at least 2 wraps on all cabling running through the conduit AND on all cabling near the antenna.

See above. Do this upfront. You'll be tracing wires and cables and might as well stick the ferrites on while you are there. They simply cannot hurt. At this point if you change the coax, connectors, and terminals and add ferrites and find the problem is solved do you really care which one or combination did it?

Originally Posted by TLSparks

Recommend you use FSK mode as CW does not normally put out any power and FSK applies a 100% modulation level tone.

Excuse me? CW is continuous power. Select CW mode and jump the terminals on the accessory (ACC) jack of the radio and you'll have full power. That's what CW is.

Incidentally, FSK switches between two tones (mark and space) based on data input. There is no modulation, just switching.

So CW is a single full-power frequency and FSK is one of two full-power frequencies. CW conveys information by being switched on and off (keyed) and FSK conveys information by switching between two frequencies.

FSK can be simulated very effectively by feeding audio tones into the microphone or other audio input with the radio set to USB or LSB (USB is the convention). Properly speaking this is AFSK. You won't get any power out without some tone injected into the audio input.

I apologize it this sound pedantic but vocabulary is important.

Short version - use CW and jump the ACC contacts indicated in your radio manual.

[TLSparks]

So John Majoring in Physics, does that mean you have a BS in Physics or what?

[SoonerSailor]

Auspicious - it is a peculiarity of the M802 that it will output a CW signal when FSK is chosen and you key the mic. No need to mess with the accessory jack.

[Auspicious]

Originally Posted by SoonerSailor

Auspicious - it is a peculiarity of the M802 that it will output a CW signal when FSK is chosen and you key the mic. No need to mess with the accessory jack.

That is peculiar. Doesn't help much for actually sending CW but I expect there aren't many of us doing that. *grin*

[TLSparks]

Originally Posted by SoonerSailor

Auspicious - it is a peculiarity of the M802 that it will output a CW signal when FSK is chosen and you key the mic. No need to mess with the accessory jack.

Actually not a peculiarity of the M802. I use the same method to teat other radios. It is actually not CW as when you key in FSK it is putting I believe a space tone, dependent on the settings of the radio. As a result it would be kind of like A4A/MCW in the SSB world. My FSK is set for the lowest frequency 1.2 kHz with the shift set at170 Hz. I have never measured it but the transmitter is putting out the carrier plus the 1.2 kHz +/- the 170 Hz (probably minus for a space condition) in USB. This is clearly adequate to check Power and SWR for a frequency.

TL Sparks

[SoonerSailor]

When you key the mike in FSK mode in the M802, it is putting out a pure carrier - a "Continuous Wave" or CW signal, not a tone. In true FSK, the radio is alternating between two pure (hopefully) carriers, typically 170 Hz apart - "space" and "mark". There is no audio tone or frequency inherent in that signal, the audio only appears in the receiver from the interaction with the BFO frequency.

AFSK on HF is different from FSK only in how the mark and space are generated within the transmitter. The signal put out onto the air is theoretically the same as with FSK.

Here is a reference: http://www.mcwa.org/AFSKvsFSK.pdf

Sorry for the thread drift.....

Chip

[Auspicious]

- .... .- -. -.- ... -.-. .... .. .--.

Now how do I do marks and spaces without a current loop and a Model 33? *grin*

[TLSparks]

Originally Posted by SoonerSailor

When you key the mike in FSK mode in the M802, it is putting out a pure carrier - a "Continuous Wave" or CW signal, not a tone. In true FSK, the radio is alternating between two pure (hopefully) carriers, typically 170 Hz apart - "space" and "mark". There is no audio tone or frequency inherent in that signal, the audio only appears in the receiver from the interaction with the BFO frequency.

AFSK on HF is different from FSK only in how the mark and space are generated within the transmitter. The signal put out onto the air is theoretically the same as with FSK.

Here is a reference: http://www.mcwa.org/AFSKvsFSK.pdf

Sorry for the thread drift.....

Chip

You are correct. However, I was trying to keep this simple and not get into radio geek details. It appears you have a reasonable understanding of communications as well so I guess my explanation should have been more like the below.

It is a clearly a continuous wave (One frequency out of the transmitter, but not that of the dial frequency. If I add a 1000 Hz tone or offset the carrier by 1000 for an upper sideband signal the transmitter transmits a signal at the frequency of the dial frequency plus the 1000 Hz. When I demodulate the signal with another SSB radio tuned to the proper dial frequency I get what? A 1000 Hz tone.

I am also sorry for the drift in the thread. It has been made perfectly clear there is only one opinion on this forum that is "correct". So if anyone really needs help feel free to email me.
TL Sparks
AD7XL
p-t_on_sunyside@live.com

[silverheels3]

Good wiring practice will route high power RF signals as far away from sensitive electronics and their associated wiring. That's all he has to do. Re route the coax run between the SSB and the tuner.

[Emerald Sea]

I don't want to highjack this thread but a solution to an issue I have with our M801 may benefit all.

Our M801/Pactor 4 has been performing normally, receiving wx forecasts, emails however recently I have had a puzzling issue with the Airmail software that perhaps someone can assist with. Airmail 3.4.062 runs from our PC with Windows 8. We are connecting lately to Brunei Bay.

Im getting a message popping up during a transmission stating "Still Calling V8V2222. Quit?" If I click either "Yes" or "Cancel" it effectively does the same thing: the SSB remains on a channel and continues to try to broadcast but there is no transmission either way. It effectively freezes. When I try to disconnect, either from Airmail or turning off the 801, it freezes Airmail and I have to reboot the computer and restart Airmail; it won't open normally after this. I have reinstalled Airmail a few times, thinking this may be a fix, but unfortunately not. Any ideas?

Also, when in the midst of a download i.e. Wx file, and the signal is lost, I restart with the same frequency and when reconnected it restarts the download from the beginning rather than recognising that a percentage has already been downloaded. Earlier on I didn't have this issue and it would restart the download where it left off. is there a setting here that is amiss?

Thanks

[silverheels3]

Could your PC be locking up due to RF feedback coming into the USB or serial connector? Try using Sailmail program in terminal wifi mode rather than through the SSB to see if you have some new issues between Win 8 and the software. We have just ordered a new modern USB to serial adaptor as the older Prolific adaptors don't work on 64 bits in Win 7 or 8