Transmit Problem w/ VHF Radio

C

Casey

New member
"Katmai" has an ICOM M422 VHF radio installed with a 4' antenna mounted on a "rocket launcher" atop the cabin.

On my recent "circumnavigation" of south Florida the VHF worked perfectly in the reception mode. On various attempts over several days I met with only marginal success getting a "radio check" along my route, and that made me think I wasn't transmitting very well, or at all. At one of the locks on the St. Lucie Canal the lock operator advised that my transmission was nearly unreadable. Some transmissions were better than others. I switched to "Hi" power, but it didn't help.

I know there are several C-Brat HAMS (no pun intended...), so I need your suggestions on a protocol for isolating my problem. (I checked with a local CB shop yesterday, and they won't even touch Marine VHF radio stuff.) For some reason I suspect the problem may be in the antenna, not the radio, but that's just my impression (it's not founded on anything...). The radio and antenna appear ok, with no obvious problem - and it receives fine, so I'm hopeful it's a relatively simple fix.

Ideas?

Best,
Casey
 
I once had a VHF problem on a former vessel and it turned out the antenna cable connection at the back of the radio had come loose - take a feel on all your cables to make sure they are securely connected if you have not already done so.

Good luck - thankfully it is easy enough to replace either the cable or the VHF to determine the problem.
 
Casey":1xp3nz8h said:
"Katmai" has an ICOM M422 VHF radio installed with a 4' antenna mounted on a "rocket launcher" atop the cabin.

On my recent "circumnavigation" of south Florida the VHF worked perfectly in the reception mode. On various attempts over several days I met with only marginal success getting a "radio check" along my route, and that made me think I wasn't transmitting very well, or at all. At one of the locks on the St. Lucie Canal the lock operator advised that my transmission was nearly unreadable. Some transmissions were better than others. I switched to "Hi" power, but it didn't help.

I know there are several C-Brat HAMS (no pun intended...), so I need your suggestions on a protocol for isolating my problem. (I checked with a local CB shop yesterday, and they won't even touch Marine VHF radio stuff.) For some reason I suspect the problem may be in the antenna, not the radio, but that's just my impression (it's not founded on anything...). The radio and antenna appear ok, with no obvious problem - and it receives fine, so I'm hopeful it's a relatively simple fix.

Ideas?

Best,
Casey
Click to expand...

Casey, before you take anything apart, try this...

There is a small hole on the handset. It's about the size of a 7mm pencil lead. That is the actual microphone. It is very easy to cover with your hand when you are grabbing the handset.

Try transmitting while ensuring that the hole is visible. My guess is that you will find the radio works just fine, and that you have been covering the mic with your hand. I spent an entire trip with an "intermittent" radio because of my ham hands. This is a common complaint with Icoms. I now hold the mic with my left hand.

Steve
 
why even have a mic grille face if its not even real? I have the same problem on my radio and have to watch where I put my hand. the little hole is right where my hand wants to fall when I pick up the mic. Who designs this stuff anyway??
 
starcrafttom":2sm0p0xk said:
Who designs this stuff anyway??
Click to expand...

As a friend of mine says, "Jason and Heather." Those are his names for all (typically) young, inexperienced techies with no real world experience. You do it that way because you can - it's electronic, and you can make it small, and you can cram lots of stuff in there, and you can pile stuff that nobody will ever use on top of other stuff that nobody will ever use, and then you hand it over to the marketing department. Jason and Heather are the ones who replaced all dials and switches with tiny black on black buttons. They also gave us cell phones that are really very low quality phones with lots of non-phone stuff crammed into them. Jason and Heather both graduated from the Rube Goldberg School of software design.

Enough ranting. This thread is all very interesting and informative. I haven't had problems that I know of with my ICOM, but I will now be on tiny microphone hole alert.
 
And the winner is: Steve, on Wandering Sagebrush!

Thanks Steve!

That was EXACTLY the problem. The microphone is on the right side of the helm. I'm right-handed. Thus when I pick up the phone my hand naturally covered the right side of the mic, and the speaker hole while my thumb activated the push-to-talk switch. Silly design - but thank you for the answer.

When I was over at the boat shop I asked one of the mechanics if he'd listen on a marine VHF when I tried to call him. He said I was "booming-in." On the otherhand, all I could hear from him was the mic breaking squelch.

A few minutes later I asked him what kind of radio he was using. He said an ICOM M320 ...same mic. same problem! I shared your answer with him, so you get credit for two fixes!

Well Done!

Best,
Casey
 
Don't feel bad Casey. All of us with ICOMs have had the same problem. My last boat had 2 of them and the problem was on both, That was the clue that let me finally figure it out. My soloution was to get a white paint pen and carefully circle the mic hole as a reminder but every one in a while, I still caught myself holding the mic the wrong way because holding it the wrong way is so natural. Just plain dumb design of the handset as the way you and I hold it is extremely common.
 
Casey":257hof9j said:
And the winner is: Steve, on Wandering Sagebrush!

Thanks Steve!

That was EXACTLY the problem. The microphone is on the right side of the helm. I'm right-handed. Thus when I pick up the phone my hand naturally covered the right side of the mic, and the speaker hole while my thumb activated the push-to-talk switch. Silly design - but thank you for the answer.

When I was over at the boat shop I asked one of the mechanics if he'd listen on a marine VHF when I tried to call him. He said I was "booming-in." On the otherhand, all I could hear from him was the mic breaking squelch.

A few minutes later I asked him what kind of radio he was using. He said an ICOM M320 ...same mic. same problem! I shared your answer with him, so you get credit for two fixes!

Well Done!

Best,
Casey
Click to expand...

Casey, thanks for the Kudos! I spent ten days in the Broughton Islands with that problem haunting me. I took everything apart when I got home, re-soldered the antenna connector. Took all in to Rodger's Marine Electronics here in Portland, and after they checked it all out (all was good), the tech said show me how you hold the mic... The rest is history. I do have two fixed mount VHFs onboard now...
 
Casey
It looks as if you found the problem. However, it might be worth while to check your antenna. The easist way is to get one of the SWR meters. There was a post about one which has several other features recently on this forum. You put the SWR meter in the line for the antenna, temporally and then measure the standing wave ratio--which tells you if the antenna is in the ball park.

I will be driving down near where you live in the next month, and would be happy to bring my ham antenna analysing gear with me, if there is any question about your antenna, or radio.
 
Thanks Bob, I appreciate the offer.

The radio appears to be working fine now that I've removed my Thumb from the mix, but let's keep in touch regarding you coming over this way.

We hope to make a (land) trip down to Key West in the next week or two, and will probably be headed back to AZ toward the end of April or early May.

At present I'm planning to trailer "Katmai" to AZ with us. The boat, and any saturated foam would certainly have a great opportunity to "dry-out" in Arizona! I may get some time up at Powell, and if we're still there in September I'd like to see the Powell CBGT Gang again. That's always a great time.

Let's stay in-touch re your travels this way, eh?

Best,
Casey
 
Casey,

Thanks much for bringing this topic up. I too had on and off transmission problems with my ICOM. After seeing your solution I realized that I was covering the mike hole with my hand. Testing confirmed this and my problem is solved.

Harper
 
Me too!
Had I known about this dangerous design defect I wouldn't have bought the damn thing. I've been using radio handsets professionally for over 20 years and had never encountered this issue before.
Even if ICOM fixes this problem I may never buy another. They have to have known about this for years.
Is Toyota their parent company? :roll:
 
Our Raymarine fixed unit has a similar situation with the mic... if you are right handed, your middle finger can easily cover the mic opening. It is to the right and above what looks like the area one would speak into.
 
Admittedly the most common mic not working problem is "the covered mic hole" but that is really not a mic problem, but an operator problem an and easy fix once learned.

Antenna connection may be an issue, however, if the problem is only in transmission, and not erratic reception too, then it is probably not the antenna.

Likely source is the mic connection. Often loose at the plug, or a wire break, usually where the wire from the mic goes into the plug, causing first intermittent connection then total loss. This can be checked for by swapping mics with one that is known not to have a problem, or by doing a continuity check on the mic wires, one by one, with the mic removed from the radio. (Might want a pro to do this one).

Glad the easy fix worked in the above cases.

Harvey
SleepyC :moon
 
Yeah Harvey, it was indeed an operator problem with me. I've been using two way radios for many years and usually pick the handset up with my right hand, palm down and key the transmit button with my thumb. This leaves the grill open between my thumb and index finger. With the ICOM handset the actual mike is a small hole low and to the right of the main grill. The way I used the handset caused my palm to cover the little hole. Testing revealed with this little hole covered, no transmission. Who'd thunk? My biggest error was not reading the details in the manual I suppose.

What really threw me off was that I had just replaced a broken antenna that was on the boat when we got her. With the broken antenna both transmission and reception were bad. Since I have very little experience with a soldering iron I assumed I had screwed something up. So, was glad to find the simple solution.

Harper
 
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