SSB Troubleshooting

[ka4wja]

You're welcome...and you've gotten some other good advice / things to check, so I won't be redundant...

So, a few more points...

--- Remember that DC ground will show on a meter, but can be far from and RF ground...
Case-in-point: Your masthead VHF antenna base (and hence the outer shield of the VHF coax) is typically secured to the aluminum mast / masthead with screws, making electrical contact....and hence the vessels 12vdc negative system (DC ground) is connected to the mast / rigging....
{some boats isolate the VHF antenna, by use of "Starboard" or GRP mounting plate, and this is screwed into the mast...but this is rare}

So, even if you have no other "ground" connection, no bonding of any chainplate, rigging, mast, etc., the rig / mast does have a tiny DC "ground" connection thru the VHF radio (thru its antenna, coax, and 12vdc negative lead)....

This of course does not "short-out" your HF signals to "ground"...


--- Further detail on using an in-insulated stay / exciting your whole rig as antenna...although, shunt-feeding, etc. has been done for decades (since the 1920's), in addition to the issues of obtaining a proper match/couple to the transmitter across wide frequency variations (mostly solved by our excellent remote tuners), questionable antenna efficiencies (mostly over-come by our low radiation angles), and the weird/unknowable patterns....(these are also reasons that most of us do not recommend use of the GAM Split-lead antenna)....
The main issue on our boats with this design is "repeatability" and RFI!!
RFI: Understand that doing this does place some (possibly significant??) RF voltage on other systems on-board....and can be a real pain to eliminate all RFI...
Repeatability: Every installation is different, and while one guy (or a dozen guys) might have reasonable success, this is not a repeatable scientific way to design / install a system....therefore, it is not recommended...

Please understand, I'm not saying it won't work....as you obviously know, it does!!
What I'm saying is that it doesn't always work, can't be relied on to always work for everyone, and therefore is not good engineering practice and is not recommended...

Oh, and most guys selling / installing HF systems actually want them to work!
And, don't want to deal with complaints, etc...nor flashing lights, etc...
So, if you follow the recommends of the likes of Sailmail / Jim Corenman, etc., you'll find little on-board RFI, and excellent repeatability...


--- BTW, your mention of the M-710/RT drawing 32 amps, made me wonder something???
(I accept that you might be showing a bit more than the typical 28 - 29 amp max draw that I've seen from M-710's and M-802's....but the fact that you mention it makes me wonder something??)
How are you measuring this??
As you should not have the SSB radio powered thru your main DC distribution panel, nor breaker panel, where most would have their panels metering showing house-bank voltage and present current draw....the radio should be wired directly to the main battery bank...

If you have a battery monitor shunt at the batteries, and have the SSB wired there, that is acceptable practice (although still not completely recommended)....

But, if the radio is wired thru your dist panel / breaker panel, this is highly not recommended, and can be a cause of much -on-board RFI...



---- Ferrites are your friend in our modern world!
And, remember, the RF chocking ability (common-mode impedance) goes up exponentially with how many times a wire passes thru the ferrite core....so, if you can pass the wire thru twice, you just gave yourself a 4-fold increase in RF choking from that ferrite....

(and, if you don't have a line isolator, get one....less than $100 USD...)



Also, be sure to have a look at these stickies (where you'll find the answers to these issues):
http://www.cruisersforum.com/forums/...tc-198305.html

http://www.cruisersforum.com/forums/...tc-133496.html




I hope this further helps...

fair winds.

John

[belizesailor]

Thanks John. I stated 32A because that is what I recall from the radio specs, but will confirm. Either way its a lot of juice.

The radio does pass thru a breaker panel, but its a separate add on small panel with just a couple of other breakers on it.

More to follow....

[Goudurix]

BelizeSailor,

Even if your setup worked in the past, nothing should stop you from optimizing your system, especially now.
Also check your power connections (heavy gauge) and power line fuses for any corrosion/bad connection.

On a catamaran I would suggest a 7.2m vertical antenna at the stern - easy & cheap based on a cheap fiberglass fishing rod at the stern and if possible midstern. You woul of course have to move the autotuner to just below the area where the vertical is installed. Run the antenna wire along the fishing rod; total of 7.2 total wire length until the ATU antenna connector lug.
Keep the ground system.

Your antenna will be further away from standing rigging. You will have a better clearer radiation pattern.

Jan
ON3ZTT

[belizesailor]

Originally Posted by Goudurix

BelizeSailor,

Even if your setup worked in the past, nothing should stop you from optimizing your system, especially now.
Also check your power connections (heavy gauge) and power line fuses for any corrosion/bad connection.

On a catamaran I would suggest a 7.2m vertical antenna at the stern - easy & cheap based on a cheap fiberglass fishing rod at the stern and if possible midstern. You woul of course have to move the autotuner to just below the area where the vertical is installed. Run the antenna wire along the fishing rod; total of 7.2 total wire length until the ATU antenna connector lug.
Keep the ground system.

Your antenna will be further away from standing rigging. You will have a better clearer radiation pattern.

Jan
ON3ZTT

True, I coulda/woulda/shoulda refine the system. The non-insulated stay install was done as a temporary...but worked so well it never got changed out.

The rest of the install is more "normal" though I expect there is room for improvement there too.

Except for the recent issue, now apparently resolved, this install has worked fine for my needs. The big advantage I think in refining the antenna rig more would be reduced RFI...and then repeatability as referenced earlier due to a more regular emission pattern.

I use my rig mostly for regional cruiser nets, weather FAX reception, and the occassional marine operator call. Has worked fine for years for all of the above.

Power install is per ICOM specs, properly sized wire, in line fuses in both sides (the standard power cable has holders built in), and then also thru a breaker. Run to house bank is relatively short (2m max).

Given that the last issue I found was a little power connection corrossion. I think I will continue inspecting down that path...and maybe this will encourage me to make some more improvements in the off seaon.

[belizesailor]

Just filled in for net control on Panama Connection Net today...rig worked fine. 8Mhz, TX on medium.

[belizesailor]

Originally Posted by belizesailor

Thanks John. I stated 32A because that is what I recall from the radio specs, but will confirm. Either way its a lot of juice.

The radio does pass thru a breaker panel, but its a separate add on small panel with just a couple of other breakers on it.

More to follow....

Looked up specs again. Max draw is 30A at 13.8V. Transmit power is 20W, 60W, and 150W at low, med, hi respectively...so quite a jump to hi.

[Goudurix]

Hi Belizesailor,

I have done some extensive modeling of antenna types on a 37ft sloop with 1 set of spreaders. Today I have a 9.2m end-fed sloper from halyard to stern sb side. But my models show a best solution (for allround behaviour 4.4-21 Mhz) from a 7.2 m vertical placed midstern. Clear repeatable patterns (at least from the model...). I can send you the files if you're interested but then again it should be remodeled for your cat and it's standing rigging. If your current system feeding a sidestay works, well...it works!
Jan
ON3ZTT