On Fri, 26 Feb 2010 08:09:34 +0000, Larry wrote:

I've been absent from the NGs for a while but found an old post about your
problems with the Icom M802 HF/SSB antenna tuner. I didn't see a message
about a resolution, though. Just wanted to ask what was wrong with it and
what fixed it.

73 DE W4CSC

Funny you should ask. As you'll recall the 802 was showing a high
SWR indication on xmit and the signal was not getting out. I checked
everything obvious and didn't find anything.

I called our local electronic techs in SWFL and it turned out that
there only HF radio guy had retired and they would have to bring
someone across the state from Ft Lauderdale at great expense.

So, I went to the MFJ website and ordered a dummy load, SWR
Bridge/power meter, and a couple of factory made coax jumpers. I
disconnected the 802 coax from the tuner and sent that to the input of
the bridge, with the output of the bridge going to the dummy load. Put
the rig on xmit using a Pactor calling sequence and the bridge showed
1:1 SWR and 120 watts output, so there's nothing wrong with the 802.

Here's the strange part. I left the 802 connected to the bridge and
sent the output to the autotuner instead of the dummy load. Went to
xmit and the SWR still looked good, the high SWR indicator on the 802
is gone, and the signal is getting out ! Disconnected the bridge and
the signal is still getting out and the 802 is still not showing a
high SWR. Go figure. Apparently there was a hidden bad coax
connection at the input of the tuner which got cleared up in the
process of installing the test equipment.

The test equipment was a good investment compared to the cost of
bringing a tech over from the east coast. I've got it aboard for our
Caribbean cruise and recently used it to help someone else get their
rig working while we were docked in the Turks and Caicos.

Wayne.B wrote in
:

Apparently there was a hidden bad coax
connection at the input of the tuner which got cleared up in the
process of installing the test equipment.


The UHF connectors are real cheap and the salt air just eats them. The
solder on the center pins makes a great battery with the metal of the
connectors, too, for some great problems. When you scraped the crap off
the solder on the center pin, all went back to connecting.

Silly me, I always take a 7/8" shrink tubing around the connectors all
the way out onto the cable, fill it with latex caulk then heat shrink it
to pressurize the caulk into all the spaces under the shrink wrap. Even
in the bilge, laying in bilge water, you can tear apart the connector
years later, peel off the latex sealing it all up and the connectors
look like the day you made them up.

Some idiot at Icom also put that stupid open pigtail to the control
cable sticking out in the sea air of the tuner. I always tear that out,
clean the soldering rings on the tuner PC board inside the sealed up
tuner, then hard solder the control cable to them after feeding the
cable properly through the compression sealed stuffing tube on the
tuner. That connector they use is just as stupid as the M802's INTERNAL
cooling sucking sea air inside the unsealed box. How dumb. The M802
should have been built in the kind of box the sealed-up M602 VHF radio
uses...with waterproof connectors, not open with a blower sucking the
sea through it.

Every couple of years, pull out the M802's main chassis, take off the
covers. Unplug all the unsealed little cables from their sockets inside
the box. Just a drop of WD-40 wiped onto the pins of the plugs, then
plug them back in. Voila! everything starts working better! The coax
connectors inside the M802 are the same crap Icom uses on the ham
stuff...open to the air. One drop of WD40 and move them around restores
a lot of noises that seem to show up. The WD will stay on them until
you do it a few years down the road. Icom could have spent another dime
and put a dollop of grease on them all during assembly....

Glad you're back on the air. Maybe I'll get the ham station reassembled
in a few months and an antenna back up. I got the bug, again, when I
renewed W4CSC once again....I got all the stuff around here somewhere
Yaesu FT-990AC loaded with every option, FT-900 mobile loaded with every
option, Hercules II I customized to get rid of all the cheap connectors
and replaced with huge power cabling throughout...650 watts OUTPUT at
13VDC. Only draws about 120 amps...(c;]

Power is our FRIEND!
73 DE W4CSC


--
"iPad is to computing what Etch-A-Sketch is to art!"

Larry