VHF Radio not transmitting.

[patrick33308]

Have a 93 Hunter 33.5, 54ft mast, 2 VHF radios, one at the nav station ( original equipment) and a new radio at the wheel. Both go thru a manual antenna switch that is in good shape, inside and little use. Antenna is a whip at the mast top.

Today I could receive on both but not transmit with either radio. Dont think it is the radio or the switch, thinking I may need a meter on the antenna wire at the mast top and also at the radios ( done 1st of course),the wire may have gone bad. Looked at the wire as in the boat as far as I could,looked ok.

Anybody ever had a similar problem ?

 

[justsomeguy]

It's doubtful that the coax has gone bad. Check/clean all your connectors, even in the switch.

 

[Bill Roosa]

try taking the switch out and transmitting into the mast cable. Switches are great places to have impedance mismatches due to even minor corrosion. The result is you can receive fine due to the every low power transiting the switch but when you try and push a couple hundred volts of VHF through it nothing happens.
if one unit is a hand held put a rubber ducky on it and transmit on the other unit to see if you are getting out

 

[Benny17441]

Check the antenna connectors, sometimes birds rest on them and foul them up.

 

[Don S/V ILLusion]

What do you mean by "could not transmit"?

 

[ISABELLA5]

Most current radios will shut down (not transmit) if the SWR (standing wave ratio) is too high. High SWR is caused by antenna to radio mismatch. Said mismatch is usually associated with connectors or cable. Even with severe mismatch local reception might not be noticed. Contact your local ham club and you will find some member with an antenna analyzer willing to check you system at no cost.

 

[patrick33308]

What do you mean by "could not transmit"?

Here in Tampa we have Sea Tow, channel 27 automatic radio check, it will play your request back to you and then continue with a recorded message. I can no longer get a response from them but hear others doing radio checks that Sea Tow responds to.

Also I do not hear myself on a handheld that I set on the same channel when I use the big radio to transmit. I use 25 watts when transmitting.

 

[Forrest15112]

Check any exposed connectors along the coax. The connectors, if exposed to the weather, will fail. I would do everything that the others here have suggested. Water damaged connectors will often look good on the outside. The wire itself doesn't "go bad", but water intrusion at the connectors ( or damaged shielding) can make it go bad.

 

[patrick33308]

Good information so far, I thank you all for your input and help.
Later to day I will use the meter and will also change the switch. Gotta get a guy to get up to the antenna at the top of the mast and do the same.
Thanks again.

 

[Bob Poff]

If you're not hearing yourself with a hand held right there, are you sure it's going into transmit at all?

Open the squelch on the hand held and transmit on the "big radio". Do you hear the hand held get quiet?

Do the front panel lights dim when you transmit?

Also I do not hear myself on a handheld that I set on the same channel when I use the big radio to transmit. I use 25 watts when transmitting.

 

[patrick33308]

So today a friend and I looked at the radios. We were able to talk with the Club on 68 100 yards away and when on 16 the handheld reacted with a squeal, so it appears that the radios are working. At least I hope so and will plan to have another boat a few miles away call me.
Still cant get a reply on 27 from Sea Tow but that issue may be theirs and not mine.

Time will tell. I thank you all again.

 

[Benny17441]

VHF is line of sight communication, if you are not positioned to transmit to Sea Tow channel 27 they will not hear you. I once had a similar problem and was able to talk to a boat standing nearby but my transmission disappeared within 200 yards. It turned out to be a fouled antenna connector at the top.