ICOM m710 not transmitting

[mikereed100]

I have an m710 with AT130 tuner and KISS counterpoise with a 40' auxillary stay antenna. I receive OK but find that I am unable to transmit. Boats in the same anchorage are unable to hear me. When I transmit, the rf meter on the radio shows full bars. I see a 3-4 amp drop in current on the battery monitor whereas I read that I should be seeing 8-14 amps. All my connections are clean and shiny, including the in-line fuses at the radio, although I am unsure how to test the power and tuner cable quick-connects to see if they may be at fault. I do hear a lot of clicking at the tuner when I key the mike or press the 'tune' button and it seems to be working well. The 'tune' indicator remains on afterward. The power is set to '3'.

I bought this system used and had a technician in Thailand check it before installing it in the boat. He said it needed some repairs but pronounced it 'fixed' when I picked it up. Any ideas?

[s/v Jedi]

Idea: find another tech

[btrayfors]

One of three things would seem to be going on:

1. the antenna/ground system (coax to tuner, tuner, GTO-15 to antenna, connections, KISS, etc.) has somehow been compromised; or

2. the radio itself has blown finals (rare in a 710); or

3. the power cable to the radio is inadequate or has been compromised thru loose connections, surface corrosion, etc.

Easiest way to check is with a power/swr meter and a dummy load to be sure the radio is capable of putting 150 watts into a 50-ohm load. If so, then the problem lies somewhere in the antenna system. If not, then the problem is in the power cable and/or the radio itself.

FYI, the M710 draws upwards of 30 amps at full output.

Bill
WA6CCA

[mfm01]

I think you may have a fault in your feeder cable. Fist check all your coax feeders do not have a short circuit by useing an ohm meter between the core and the outer sheild should be more than 700 thousand ohms ( 700k ohms), if that is ok then make a short circuit at one end of each feeder cable and measure the resistance you shoud then have no or very little resistance 5 or 6 ohms, if all checks out ok then diconect your ATU and connect your antenna feeder directly to your radio, although it will not be matched correctly it will still work but set it to power setting 1 when testing.
best of luck
MFM01

[mikereed100]

Thanks for the responses. I re-checked the power cable connections and all is tight and shiny. I then checked the feeder cable usng the proceedure mfm01 suggested and all is well there too. I forgot to mention that I had the radio checked by a tech in Kodiak who replaced the PL259 connectors on the cable and pronounced all is well. He did not check transmission in detail but seemed satisfied that the rf meter on the radio read full power.

Interestingly, when I connected the feeder cable directly to the antenna and transmitted on low power as suggested above the radio drew 7 amps, as opposed to 4 amps at high power with the AT130 inline. This seems suggestive of a problem with the tuner or the cabling? The control cable is new but the quick connect on the radio side is not. The tuner seems to be working well otherwise; lots of clickety clacks and the LED indicating successful tuning lights up under the selector switch.

I don't have a power/SWR meter and am currently in the Sea of Cortez so options here are limited. I will try to rig up a light bulb dummy load to see if that gives me any clues.

[Mirage35]

FWIW from experience a long time ago, some Icom models had a fuse directly on the output which would blow and save the expensive bits if you tried to transmit with no antenna / seriously mismatched antenna. It was internal and not obvious - or at least not to me. It took me a while to realize that was why I was no longer transmitting.

[SecondWind90814]

When you key the Mike and talk does the RF indicator substantially increase in step with your voice?

If not, clean microphone connections. If that doesn't help, borrow another know good Icom mic from someone with a Icom 710 radio and try that Mic. If that solves the problem get a replacement mic. If it doesn't, and everything else fails, take to a shop.

[seasick]

There will be no power draw on your 710 when keying a silent mike so you need to use the tune facility which sends a modulated sound and also tunes the antenna.

Check the rear fuse for corrosion.
AE7DI

[mikereed100]

Well, it seems I have figured out my hardware problem. There isn't one. I was trying to transmit on a frequency that is not allowed on my radio. When I transmit on the allowed frequencies the radio puts out plenty of power, the lights dim, the LEDs light up etc. Apparently the M710 is a SSB only radio and cannot transmit on ham frequencies? Page 23 of my manual lists the available transmit frequencies which do not include any of the ham nets. Bummer. Makes me wonder why I got my ham license.

So my new question becomes; is there any way to program the m710 to transmit on ham frequencies?

[btrayfors]

Originally Posted by mikereed100

Well, it seems I have figured out my hardware problem. There isn't one. I was trying to transmit on a frequency that is not allowed on my radio. When I transmit on the allowed frequencies the radio puts out plenty of power, the lights dim, the LEDs light up etc. Apparently the M710 is a SSB only radio and cannot transmit on ham frequencies? Page 23 of my manual lists the available transmit frequencies which do not include any of the ham nets. Bummer. Makes me wonder why I got my ham license.

So my new question becomes; is there any way to program the m710 to transmit on ham frequencies?

There were several models of the M710, including the M710/RT (with remote control head). I believe that most of them are quite capable of transmitting on the ham bands, right out of the box.

Note that frequencies can only be programmed into the 160 user programmable channels, not the pre-existing ITU channels.

Suggest you try the following:

Icom M710 Programming Instructions

Note that the Specifications only show frequency ranges for which the radio is type-approved, i.e., for the marine bands. However, if you'll note the list to the right of that page shows the radio capable of receiving LSB as well as USB and AM emissions. It will also transmit on LSB outside the marine bands, e.g., on the ham bands.

On terminology, note that the ham bands are also SSB. Most use USB but those below 10MHz use LSB, apart from the 5 channelized frequencies in the 60-meter band which are USB.

Here's an excellent primer on the M710. It's a bit dated, but skip down to the programming stuff.
https://www.cruisingclub.org/pdfs/com_using_icom_m710_m710rt.pdf

Bill
WA6CCA

[wayne.b]

Originally Posted by mikereed100

Well, it seems I have figured out my hardware problem. There isn't one. I was trying to transmit on a frequency that is not allowed on my radio. When I transmit on the allowed frequencies the radio puts out plenty of power, the lights dim, the LEDs light up etc. Apparently the M710 is a SSB only radio and cannot transmit on ham frequencies? Page 23 of my manual lists the available transmit frequencies which do not include any of the ham nets. Bummer. Makes me wonder why I got my ham license.

So my new question becomes; is there any way to program the m710 to transmit on ham frequencies?

===

Apparently you need a software program and special cable assembly. More information here:

https://www.ssca.org/forum/viewtopic.php?f=5&t=1697

[seasick]

Your M710 can be modified for the ham bands but I don't recommend it. It is a firmware update. The necessary cable to connect it to a PC isn't cheap. You have to allocate channels to commonly used frequencies like 14.300. This is ok for Pactor or Winmail but impractical if you have to shift up 3khz to find clear ether. I recommend keeping an eye out for an FT 840 or other robust rig.

[btrayfors]

I don't believe the last two posts are correct.

I've programmed many M710s, using the cable and software, but this is NOT necessary to transmit on the ham bands. It is rather a convenience, since desired frequencies can be set up for all 160 user programmable channels and cloned in just a few minutes, rather than entering them by hand which could take an hour or two.

But, you CAN just enter a few desired ham frequencies by hand, following the instructions on Dockside Radio's site as referenced above.

Seasick is correct in that the M710 is not ideal as a ham radio because it's clumsy entering frequencies, as there's no real VFO. There is a sort of workaround which will allow ham-like VFO operation, but it's a bit clunky.

Nevertheless, the M710 is an excellent radio and works very well on both the ham bands and the marine bands, especially if all you want/need is to listen or transmit on preset channels/frequencies.

Bill
WA6CCA

[s/v Jedi]

I agree with Bill, my 710/RT works great on HAM bands. I also have a Kenwood 200W HAM radio and I never had it outperform the 710 on transmit even though it is only 150W.

For true HAM hobby, as well as receive filtering etc. the HAM radios are better but most HAM's on boats just use a select number of freqs that can easily be programmed in user channels.

I hate the channel programming of Icom; it is way too complex and the manual is as bad. Just opening the Kenwood manual is a relief but the 710 is a solid radio nonetheless.

[mikereed100]

Bill,

Thanks for the links. I tried programming the transmit frequencies into the m710 using the procedure described by Dockside, which is the same procedure as in the 710 manual, but the radio will not allow me to program transmit frequencies in the 3.0 to 3.9999Mhz range nor the other frequencies not listed under transmit frequency coverage on page 23 of the manual as shown below. I am using the user programmable channels. When I get to the step where I press 'Tx' after entering the new frequency the frequency simply reverts to the previous frequency. I have no problem programming the transmit frequency using the 'allowed' frequencies. I am sure there must be a way around this as so many cruisers are using the m710 including those I hear (but can't talk to) on the ham nets.