Icom 718 HF RadioWon't Tune

[jls095]

Hi all - My boat came with an Icom 718 HF radio and an AT-130 tuner. The radio powers on but will not tune via the "Tuner" function. "Tune" flashes but then disappears. I figured the issue was with the antenna and ground so I replaced both.

I used heavy gauge grounding strap to connect the tuner to a thruhull (as the previous owner had done). The original grounding strap was partially chafed through.

I ran a new antenna cable (GTO high voltage cable) from the tuner up to the backstay insulator. The old one was corroded at the attachment to the backstay.

When I had the cover off, the tuner showed no signs of corrosion. Am I missing something obvious?

For what it's worth, at the slip I cannot hear anything but alien noises on LSB and USB bands. I can pick up a few AM stations.

Appreciate the help!

[roverhi]

Had the same problem with my 718. Turned out to be a fault with the radio not communicating with the AH-4 tuner. Didn't have the time to send radio back to Icom for a fix so bought a SGC 230 tuner. The SGC 230 tunes off the radio's rf output not from a special signal sent to the tuner as the Icom radio/tuners do. Worked perfectly and never did get radio fixed. Sold the AH-4 tuner for what I paid for it. A competent tech can test for the radio sending the signal to the tuner if you don't want to buy a SGC 230 and/or want to be sure it's a radio fault causing the issue.

Had really poor reception and transmit in the marina. Too much interference with masts and other stuff in those close quarters.

[CarstenWL]

... you can also try to tune 'with a steady carrier' (e.g. selecting AM on the ICOM and use the mic to go to TX or CW and use a key / 'short' at the key input). You should do this with a dummy load connected to the tuner to get familiar with the tuning and avoid 'transmitting a signal on the air'.

I guess you know that the AT-130 is a manual tuner from Kenwood (and no auto tuner like the AH-4 or AT-180 from ICOM).

I ran a new antenna cable (GTO high voltage cable) from the tuner up to the backstay insulator. The old one was corroded at the attachment to the backstay.

If you really have the AT-130 from Kenwood I question how you connected 'the wire' to the PL259 connector on the tuner.

Regards,

Carsten

PS: See p.28/29 of the ICOM manual: https://tinyurl.com/y9bkf6vb

[Hartleyg]

Carsten, ICOM has a line of marine auto-tuners: AT-120, AT-130, etc. They are good tuners, but need a couple signalling wires from the radio to the tuner to make them work.
If this control cable is broken, dislodged, etc., or the tuner isn't receiving power then the tuner won't work properly.

jls095, I would take a hard look at the control wiring between the radio and tuner - a voltmeter will tell you if the power connection is "live".

A couple good frequencies to check would be 5, 10 and 15 MHz for WWV, or 14.275-14.350 MHz on USB mode during the day.

73 DE Hartley

[Ocean Cowbuoy]

I have a SEA ssb and had same problem. I looked at all the connections and everything seemed fine so I had a couple cold beers while I sat at the nav table and read the manual on how to turn off, then turn on again, the tuner function. Did that and it worked....so I had a couple more beer and played with the radio......which I don't usually do as I find not much SSB traffic these days.

[CarstenWL]

@Hartleyg:

Thanks for the heads up. Was not aware there was a AT-129/130 from ICOM, seems they never made it to Germany, only know the AT-180 / AH-4.

73ss

Carsten

[jls095]

We have some progress! I moved the ground from a thruhull temporarily to the shaft and now it tunes. That said, the SWR is still high (around 3) on most frequencies so I have to figure out what's causing that. I also wasn't able to pick anything up last night other than some AM stations, but I'm not sure if that's because something is wrong or there just isn't any traffic.

Think I'm going to buy the KISS counterpoise as the solution to the ground.