'swr' Error on Icom M802

[whalewatcher]

hi all.
i can't transmit on my ic m802. receives well but i just get an "swr" error when i key the mike. i have a brand new antenna and full voltage at the unit. i made up a parallel ground to the at-140 to make sure i had good counterpoise. boat is all aluminum. voltage goes from 14.2 to 13.7 when i key the mike. any ideas?

apologies if this has been covered elsewhere. mods, feel free to move this if it has been covered already. cheers.

[btrayfors]

Sounds like you have a short, or an open somewhere in the antenna system. "System" includes the coax between the main unit and the tuner, the connectors on each end of this coax, the tuner itself, the GTO-15 wire to the antenna, the antenna itself and connections to it, and whatever you're using for an RF ground. The radio is telling you that there's a mismatch somewhere.

Simple troubleshooting tools include a multimeter, a pwr/swr meter, and a dummy load. With these tools available it should only take a few minutes to discover where the problem lies. Without them, you're shooting blind.

Bill

[whalewatcher]

thanks, bill. yup, i checked for open circuits on all. no faults that i could find. even sent the whole kit to icom to make sure it was all good. i must be overlooking something with the antenna system, i agree.

[btrayfors]

Originally Posted by whalewatcher

thanks, bill. yup, i checked for open circuits on all. no faults that i could find. even sent the whole kit to icom to make sure it was all good. i must be overlooking something with the antenna system, i agree.

Don't know where you're located, but you might try to find a local ham with a dummy load and a pwr/swr meter. These, and the multimeter I'm sure you have aboard should make short work of troubleshooting.

[whalewatcher]

Originally Posted by btrayfors

Don't know where you're located, but you might try to find a local ham with a dummy load and a pwr/swr meter. These, and the multimeter I'm sure you have aboard should make short work of troubleshooting.

Located out on Nantucket. Tough finding help out here. Guess I'll just keep plugging away. Thanks much for your insight. Cheers.

[btrayfors]

Originally Posted by whalewatcher

Located out on Nantucket. Tough finding help out here. Guess I'll just keep plugging away. Thanks much for your insight. Cheers.

You just might be surprised. Here are 28 hams who live on Nantucket:

K1JKV FRANCIS W PEASE, 166 HUMMOCK POND RD, NANTUCKET, MA, 02554

K1NGJ Eldridge B Norton, 39 Hooper Farm Rd, Nantucket, MA, 02554

K2LEK MICHAEL WODYNSKI, PO Box 854, Nantucket, MA, 02554

KA1WFX LORE M RICHARD, 12 MADAKET RD, PO BOX 57, NANTUCKET, MA, 02554

KA1YMJ James A Ozias, 22 Lovers Ln, Nantucket, MA, 02554

KB1NG DAVID J LEGGETT, 262 MADAKET RD, NANTUCKET, MA, 02554

N1JYV Edward E Benham, 55 A Polpis Rd, Nantucket, MA, 02554

N1NBQ GEORGE F ALLEN, PO BOX 727, NANTUCKET, MA, 025540727

N1NBR Glenn A Mc Garvey, 82 A Old South Road, Nantucket, MA, 02554

N1OYC LOUISE L OZIAS, 22 LOVERS LN, NANTUCKET, MA, 02554

N1YFE ROBERT J THOMPSON, 3 GOLF VIEW DR, NANTUCKET, MA, 025542767

W1NQT KENNETH T BLACKSHAW, 4 Sandwich Road, Nantucket, MA, 02554

WA1DQJ VALERIE A HALL, 65 POLPIS RD, NANTUCKET, MA, 02554

KB1ECD JEDEDIYAH F WILLIAMS, 13 DENNIS DR, NANTUCKET, MA, 02554

KB1EPW Paul Connelly, 53 Hooper Farm Road, NANTUCKET, MA, 025544109

W1ACK DAVID C GRAY, SR, 11 FRIENDSHIP LN, NANTUCKET, MA, 02554

K1ACK CHRIS T WILSON, 76 PLEASANT ST, NANTUCKET, MA, 02554

KB1IHF Ronald E Russell, 4 Washaman Ave, Nantucket, MA, 02554

KB1IHE Linda R Natsis, 195C Hummock Pond Rd, Nantucket, MA, 02554

W1PJR PHILLIP J RANERI, 1 SHEEP COMMONS LANE, NANTUCKET, MA, 02554

W1TJM TERRILL J MALVESTI, 20 Vesper Ln Unit A1, Nantucket, MA, 02554

KB1KYN Andrew H Bennett, PO BOX 1333, Nantucket, MA, 02554

KB1MCF Joseph M Swain, Jr, 19 Friendship Ln, Nantucket, MA, 02554

W1TUK Albert W Jenkins, 5 Daley Ct, PO BOX 1162, Nantucket, MA, 02554

W2BTA Robert B Lang, 10 Hussey Farm Rd, Nantucket, MA, 02554

W1RRH ROBERT R HALL, 65 POLPIS RD, NANTUCKET, MA, 02554

KB1POC Daniel Rezendes, 30 Tashma Ln, Nantucket, MA, 02554

KB1QIS Bradford C Ames, 10 Green Meadows Ln, Nantucket, MA, 02554

Hams are generally very helpful, and glad to provide assistance if needed.

Good luck,

Bill

[ka4wja]

Whalewatcher,
Bill has given you some good input, his direct and detailed paragraph summed up what is going on.....


And, I'd love to help as well.....
However, with the limited info you provided, the best that anyone can do is make shotgun guesses....




Here are just a few examples of info/clarifications that would make it easier to get a handle on what's happening:

a) Your post's "subject" is 'swr' error on Icom M802, but then you write that "i can't transmit on my ic m802. receives well but i just get an "swr" error when i key the mike."

So, can we assume that the 802 is transmitting, but that the RF output is low, due to its sensing a high swr, and you've been unable to contact anyone with it????
{I'm goning to assume, yes...}

And, can we assume that since it "receives well", your coax connection between the AT-140 and M-802 is okay???
{NO we can't assume that, since depending on conditions and stations heard, you could receive decent signals with a coat hanger for a receive antenna....}

And, not knowing who/what you are receiving, means we cannot evaluate this aspect much further....
{Have a listen for NMF, USCG out of Boston.....their 4mhz and 6mhz WeFax and 8mhz SITOR signals should be pretty strong in Nantucket.... Boston Radiofax Schedule with Links
USCG HF SITOR }


b) We can assume that you don't have an external power/swr meter, but have you have verified the RF output by use of the M802's display RF output meter????
Remember that you will have no output on USB or LSB from just keying the mic, without speaking......so use the FSK mode, where the M-802 will transmit a unmodulated carrier, when the mic is keyed....and watch how far the RF output display deflects....assumng you're configured to "Hi-Power", you should see at least 2 bars of output, even with "swr" flashing.....
{My guess is that you'll have 2 - 3 bars of deflection....}



c) Are all your AT-140 power/control connections wired correctly????
(check those little bugger plugs, on the AT-140, and on the M-802's "tuner" connector....and make sure you do have proper voltage at the AT-140....)
{If you wish for a "first place to start", this is it!!!!}
And, a close "second place" would be the coax connections, both ends, between the M-802 and AT-140.....(a shorted or intermittent coax connection would cause the symptons you desribe....)
And if you got a line isolator (a good idea to have one), check those connections as well....
{I put this section in bold-type, so that you'll notice it....as it unlikely that you pulled the wiring / coax out of your boat an sent that to Icom to be "checked-out", so with the limited info provided, these are my best guesses for a #1 and #2 place to start looking for your problem....}



d) Are the menu settings on the M-802 configured correctly to use the tuner that you have???? (AT-140???)
{Although Icom should've done this, it's a very easy to verify item....}


e) After checking the tuner control wiring and plugs (both ends!), and the coax between the M-802 and AT-140 (both ends!!), have you verified that the AT-140 is working, by listening to it, as someone pushes the "TUNE" button (placing the M-802 into a 10-watt transmit)???
You should hear some relays clicking, assuming someone is providing it some RF????
{If you've checked all the tuner wiring/connections, coax and control cables, and verified the voltages are correct, you should hear the relays....if don't hear anything, and still have "swr" flashing, then I'd suspect a intermittent tuner (a rare occurance)...}


f) Also don't forget to make sure that you have sufficient DC power supplied to the M-802 (large enough power wiring)????

g) You wrote it was new, but what are you using for an antenna??? And, how is your GTO-15 wiring run???? {Always an important issue, as the GTO-15 IS part of your "antenna", but in your case, as you have an alum boat, I wonder if you may have some amount of your transmitted energy being radiated inside the boat, possibly causing some transmit RFI???? As transmit RFI on-board can cause the M-802 to indicate "swr" when infact the AT-140 is working properly and supplying your 802 with a good match...rare, but it can happen...}


h) Not sure I understand what a "parallel ground" is.....
But, with an alum boat, I'd simply use some hi-voltage caps, to DC isolate the RF ground connection from the AT-140 to the alum hull......(making sure you use caustion with any dissimilar metals as well...)
Perhaps there is an issue with your RF ground system (again, I'm not sure what a "parallel ground" is)????


There's a lot more....but that's enough for now...
Whalewatcher, as you can see Bill's brief paragraph uncovers a whole host of "possibilities".....(there are many more than listed here...)
But, without further info from you, we're just guessing.....

And, BTW, I agree completely with what Bill wrote......with a simple multimeter, an swr/power meter, and a dummy load (a 150 watt light bulb can do in a pinch), you can track down many radio problems in a few minutes.....
{But, please take note that if you do the troubleshooting steps I wrote above, all you need is a simple multimeter (something every boat should have, and somethimg you can buy at any hardware store in the US), and you may find your problem in short order......although, you should still have a power/swr meter and dummy load!!!!}


Good luck and Fair winds...

John

[fairbank56]

Are you pressing the TUNE button before trying to transmit? What indications to you get on the display when you press the TUNE button? Pressing the PTT on the mic does not cause the tuner to tune unless you have set automatic tune to ON in the initial set mode. The default setting for that is OFF.

Eric

[Krakato]

If you are up to paying about $250, an antenna analyzer is a great piece of equipment to have. http://www.aesham.com/photos2/MFJ249B.jpg I have one of these and use it all the time to track down antenna problems for myself and friends.

Also curious what it does if you take the AT out of the circuit. It could be that the AT has failed in some strange state.

Cheers,
Mike
NW5M

[stormsurf]

Thanks Bill, John et al very much for all the responses. I just got an MFJ-259B analyzer but am not very savy with it yet. Any help with that unit would be appreciated. Since the antenna coax plugs into it, not sure how one measures swr and tunes the radio. Guess I have some reading to do. Should I also get a "Cantenna" dummy load? What will the dummy load tell me? (Sorry to be so "green" with this stuff)

Back to the problem. I should mention that the unit worked fine up until a few months ago. I have the radio on auto-tune and all other connections and menu items are correct. Having used my multimeter, I know there are no faults in any of the coax or connectors. I ran a second 2 gauge ground wire from my tuner(I incorrectly called it a "parallel" ground). Icom checked out both the head and the tuner. As mentioned earlier, I have a new antenna(Shakespear 23' whip). I know about talking when keying the mic. I have received conversations from South Africa and other distant points. Also the WLO wx midday on channel 29. I will try the RF output meter on the unit. I wasn't aware of that feature .

Again, thanks so much for all the help. Cheers.

[donradcliffe]

Aha! So things worked fine until you installed the new antenna??

[stormsurf]

Originally Posted by donradcliffe

Aha! So things worked fine until you installed the new antenna??

Lol. Nope. I just assumed that salt had taken its toll. Corrosion at that connector. I replaced that, as well.

[btrayfors]

Stormsurf,

Well, the analyzer is a bit of overkill for this purpose, but you might find it useful in the future.

What you can do is to first tune the 802 up on a marine frequency...say 8152 kHz....then without changing anything unscrew the coax from the back of the radio and connect it to the SO-239 atop the MFJ 259 analyzer. Now, set the frequency range on the analyzer (right-hand knob) to -- in this case -- 4-10. Now, turn on the analyzer and turn the left-hand Tune knob until you get to the same frequency you should be tuned up on, i.e., 8152 in this case.

Now, read the SWR at the top right hand corner of the display. It should be low, i.e., less than about 1.2. If it's higher, then your antenna system isn't tuned up right. That could be a problem with: (1) the tuner itself; (2) the coax or its connectors between the 802 and the tuner; (3) the control cable or its connectors between the 802 and the tuner; (4) the RF ground system; (5) the GTO-15 transmission line between the tuner and the antenna; or (6) the antenna itself.

What you really need is an external Power/SWR meter which will give you an excellent indication of how much power the radio is putting out, and how much is being reflected back. A decent one costs $99 on line (e.g., the Daiwa CN-101L from Chuck Martin RF or from HRO).

If you're planning to get a dummy load...and it's good to have one around...DO NOT get the cantenna. It's huge and suitable only for use in the home shop or ham shack. The MFJ model MFJ-260C is compact and suitable for this use, and is easy to stow.

To use the meter and the dummy load, you'll need a couple of pigtails. Make these up from scrap RG-8X coax, each about 2' long, and with a PL-259 connector at each end. Be sure to put the connectors on carefully and check them with a multimeter to be sure there are no shorts (between the center conductor and the shield) or open circuits between the ends.

By the way, you probably want to remove the "parallel ground". You don't want ground loops.

Good luck,

Bill
WA6CCA

[ka4wja]

stormsurf,
Are you and whalewatcher the same guy???
Are we still discussing the same set-up / problem???
(If I knew your name, I wouldn't be so confused...

John
s/v Annie Laurie

[stormsurf]

Originally Posted by ka4wja

stormsurf,
Are you and whalewatcher the same guy???
Are we still discussing the same set-up / problem???
(If I knew your name, I wouldn't be so confused...

John
s/v Annie Laurie

Yep. Same guy. Different computer remembered my login info when I didn't.