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nelson.peter · 02-05-2009, 18:50

I'll start off by saying I am mechanically inclined, but I have met my match with understanding SSB's! My son and I just finished installing our Icom M802 SSB w/ AT-140 tuner and Pactor III usb modem. We went to test it today.

The receiver is working fine. But we cannot transmit. When we push 'thru/tune' we have read that we are supposed to see 'tune' flash 3x. Well, it flashes once and the display immediately goes back to showing 'thru'. When we try to transmit, and use the mic, the ammeter jumps, 'TX' shows on the display, but nothing else.

I know the AT-140 and antenna works, or we wouldn't be receiving. So I am thinking maybe we screwed up on the ground plane. We ran 100 lineal feet of 3" copper foil. We started at the AT-140, went about 6' and hooked into a thru-hull (via a hose clamp). From there, I stapled a 'field' of the foil under the stbd. bunk (and above the fuel tank) for another 25 sq.ft. or so of plane. I ran out of my first 50' of foil.

I took the 2nd roll and tapped a keel bolt, into a head where I picked up another thru-hull, over to the water tank, picked up the engine block, then soldered and mechanically screwed the 2 foil rolls together. From there I went into another head and got another thru-hull (for a total of 3) and then to the SSB transceiver.

I mean, this seems like the mother of all ground plane installations to me! Did I overdo it? What did I do wrong? At both the transceiver and AT-140 I doubled or tripled the thickness of the foil and punched a hole in it and attached it to the ground screw.

Can anyone help us figure out what went wrong? The installation manual from Icom has zero on troubleshooting. Thank you in advance.

Microship · 02-05-2009, 19:14

Without being able to play with it, I can't say for sure, but here's a data point. Just about anything hanging on the antenna connector will let it receive convincingly, so that does not necessarily mean that the tuner, cabling, and antenna are OK. Many rigs react to intolerable SWR (mismatch) by just refusing to stay in transmit mode, so my first checks would be:

- Coax to tuner, test for continuity inside and outside, and shorts between them. This is probably OK.

- Control cable to tuner... is the AT-140 clicking or otherwise reacting when you power the rig and attempt to transmit? If not, this is suspicious.

- GTO-15 or whatever from tuner to backstay... check continuity, just in case. Old corroded backstays or too-gentle tightening can create a high-resistance point there.

- The ground system you describe is probably very good in the RF domain, though all those potential DC loops bother me a little. There are endless debates about single-point grounding systems. I'm paranoid about that, with my steel boat, so I use a huge Mica capacitor in the grounding of the tuner. But it's unlikely that would cause the problem you are seeing unless something is open.

Cheers and good luck!
Steve

CSY Man · 03-05-2009, 00:54

Got the right code typed in for inital programming..?

Had a brand new 802 a few years ago that would not transmit or receive and had to send it back..Something about SSMI code not being right and the stupid thing will lock up after the 2nd attmept.

nelson.peter · 03-05-2009, 04:34

Thanks for the input. We'll check the connections between the tuner and antenna especially. I am pretty sure we got the connections between the tuner and main unit good. But I want to check the connection between the GTO-15 and backstay. I just shoved that small coax wire in with the backstay (rather than screwing it into its own receptacle on the clamp). It may not be making good connection.

When we power the SSB on and off, the AT-140 clicks. But when we try to tranmit (by hitting the mic button), it clicks the first time, but not after that. Curious!

richardhula · 06-05-2009, 02:39

As well as above suggestions check specifically the AT140 control cable connectors particularly at the tuner end. The pins should be captive within the nylon connector but sometimes come loose.

Check the ground terminal on main M802 unit is connected to ground or better still to ground plain copper foil. Mine runs as copper foil from AT140 to M802 continuous. Sounds like your installation is ok in this respect though.

If after tuning you get only "THRU" indication this means that tuner is not doing it's job. When you transmit SWR will be bad so transmitter will shut down. Do you see "SWR" indication flickering when pressing transmit? If so then above suggestions should reveal/fix problem.

When it's working properly indication should show "TUNE" before, during & after transmitting.

Regards

nelson.peter · 06-05-2009, 06:10

Thanks for input. We do not see 'SWR' anywhere on the display. But I suspect the AT-140 as well and will check connections.

One time when the SSB was on but not yet fully operational, the AT-140 made loud, clicking sounds for about 15-20 sec. and then stopped. I wonder if something was getting fried in the AT-140. When I mentioned this to Icom, they dismissed it.

Hampus · 06-05-2009, 06:12

In addition to everything already said; go from the lowest frequency to the highest and try to transmit at a couple of different frequencies within each band. Usually, a couple of frequencies in the lower range, depending on your antenna length, will still work even if the tuner does not. Also, try to lengthen the antenna by splicing in a cable between the tuner and your aft stay. This could help if you only experience problems on higher frequencies.

nelson.peter · 06-05-2009, 06:20

I tried your suggestion...I went to different frequency bands and hit the mic button. When I go to a new band, the display will switch from 'thru' to 'tune' once, then go back to 'thru'. So it seems like the tuner is trying to find the channel or band. But when I try to transmit again on any channel within that band, I don't get any change in the display.

fairbank56 · 06-05-2009, 10:45

Make sure the "external antenna tuner type" is set for AT-140 which is the default setting. If you want the tuner to tune when pressing the mic button as opposed to using the tune button, you must have "Automatic tune" set to "on". The default is "off". You can change these settings in "initial set mode" (refer to the manual). When you press "tune", the radio sends a "start" signal to the tuner via the white wire in the 4 conductor tuner cable. The tuner then keys the radio via the green wire. The radio will transmit a 10w cw signal. The radio should show "tune" flashing and "tx" and you should hear a buzzing sound from the tuner which are the relays. If the tuner does not detect power from the radio, it will not initiate tuning, you won't hear the buzzing and the radio will unkey and show "thru".

Eric

nelson.peter · 06-05-2009, 18:36

OK, I am going to fess up here. It would be real easy to say 'thank you' to everyone and go quietly in the night. But besides a big 'thank you', there is also a bit of an apology. Why?

Well, based on fairbank56's comments, I finally went back to the tuner and have a look around. I can't say for sure, but I am pretty sure we had the dang white plug on the control cable in backwards! Red was going to green and white to black (or whatever). I put the plug together with the colors matching, and it's magic! We now have 'tune' on our display and the radio appears to be operating normally.

I say 'appears' because I don't know how or where to do a radio check. I called the USCG on VHF and was told they don't do radio checks. (That was kind of what I figured they would say, but I also thought it a little strange since isn't a radio part of the safety equipment of the boat?!!)

Anyway, if you have any ideas for doing a legitimate radio check, I'd like to hear them. And thank you to you guys for helping me get the courage up and wade through this intimidating monster of a SSB installation!!

CSY Man · 07-05-2009, 14:33

PLenty of commercial stations doing a radio check..Try WLO

Karend007 · 26-02-2015, 12:46

Quote:

Originally Posted by fairbank56

Make sure the "external antenna tuner type" is set for AT-140 which is the default setting. If you want the tuner to tune when pressing the mic button as opposed to using the tune button, you must have "Automatic tune" set to "on". The default is "off". You can change these settings in "initial set mode" (refer to the manual). When you press "tune", the radio sends a "start" signal to the tuner via the white wire in the 4 conductor tuner cable. The tuner then keys the radio via the green wire. The radio will transmit a 10w cw signal. The radio should show "tune" flashing and "tx" and you should hear a buzzing sound from the tuner which are the relays. If the tuner does not detect power from the radio, it will not initiate tuning, you won't hear the buzzing and the radio will unkey and show "thru".

Eric

Eric,
I have the same problem (won't tune) but it has only started happening recently (7 year old installation). Have cleaned all the connections to the tuner and even checked the plug on the tuner controller within the radio. When I speak or whistle in the mic, I get no signal strength bars on the display, so I am thinking no power from the radio as you say above. What could cause this?
Thanks
Karen