VHF Transmit indicator says it's working, but is it?

[coastalrichard]

I admit having zero electrical experience or acumen and also must admit to delay in determining this apparent fault in my VHF. Since acquiring the boat I have monitored channel 22 for traffic but never actually performed a radio check until this past weekend. I can hear the traffic but, when I attempted to hail "any vessel" for a radio check, I got no response. The transmit light comes on but no reply...none and I know the location of some of the other boaters (we're within range). It's a standard, white Shakespear mast. How do I troubleshoot?

 

[NYBo]

Re: VHF Transmit indicator says it's working, but is it?

The standard hailing channel is 16, so maybe no one is listening. Of course, local custom may dictate the use of another channel (in possible violation of the law to monitor 16 when the radio is on and not transmitting on another channel). The Coast Guard uses 22 (actually, 22A) to broadcast safety information.

 

[coastalrichard]

Re: VHF Transmit indicator says it's working, but is it?

Well, our local commercial traffic channel is 22. I can hear the traffic but no reply when hailing. USCG gets frosty when we use 16 for this kind of stuff (I've heard others try it!)

 

[sasto]

Re: VHF Transmit indicator says it's working, but is it?

Boat US has a channel for your radio check, Richard. Here in S. FL the channel is 27. Give it a try.

 

[coastalrichard]

Re: VHF Transmit indicator says it's working, but is it?

Gotcha bud...I'll give it a try in the am. Would damage to the top of the mast affect transmission? I ask because as I examine it, the top of the mast looks like it has a 4" "wispy tail" (string tail?)?

 

[fairbank56]

Re: VHF Transmit indicator says it's working, but is it?

Channel 22 is an international duplex ship to shore channel. You cannot communicate ship to ship on this channel. Channel 22A is a simplex ship to ship channel. The questions are, what channel are you on and what channel is the traffic that you are hearing on? The reason you get no response may be that they cannot hear you at all because you are really on different channels and/or they don't have the time or inclination to answer radio check calls. This is not the channel to be doing that on.

If you are sure the traffic is coming from a ship, then you must be on 22A. If they are communicating ship to shore on channel 22, they will not hear you calling because 22 receives on a different frequency.

Eric

 

[Jlawsen]

Re: VHF Transmit indicator says it's working, but is it?

Do your radio checks on channel 69. That's open for use by all pleasure craft. The odds of getting a response on 69 are usually a lot better. My radio is set to scan both 69 and 16. Bridge to Bridge channels are for commercial vessel use and pleasure vessels should not use them. Channel 16 is to be monitored but not transmitted on unless it is an emergency.

Your antenna with it's fractured tip and whispy tail is not doing your radio any favors. All communications antennas are designed for a specific wave length. You don't have room for a full wave antenna so they are usually 1/4 wave and coupled (trimmed) at the transceiver for the optimal SWR (standing wave ratio) of 1:1. If the length of your current antenna is less than it's original design or not designed for the frequency range of your transciever your SWR ratio will not be optimal and your transmit range will most likely be poor.

 

[coastalrichard]

Re: VHF Transmit indicator says it's working, but is it?

Great info folks...thanks. I called one of our guide captains last night and he informed me that folks use 11, not 22, as I had thought. Hey, I learned alot...thanks again.

 

[coastalrichard]

Re: VHF Transmit indicator says it's working, but is it?

OK, I replaced the broken antenae with an 8' whip today and came upon something I did not expect. The kit came with the antenae and coax cable of about 10' along with a threaded coupler that looked exactly like what was connected to the back of the transceiver. I removed the old whip, installed the new one and fed the coax thru the hull fitting into the area beneath the helm. I disconnected the old cable at the back of the unit and pulled it out only to notice that it was hard wired to a "AM/FM VHF Marine Band Separator" which was, in turn, connected to the free end of the coax coming from the antenae. I put all new connections back together in the same manner as I found it...antenae to seperator, separator to VHF. The was also a hard wire connection from the separator to my AM/FM unit.

Still no luck in hailing anyone on numerous channels 11, 27, 67 and 69. But I did notice that when listening, the screen indicated "Busy" at all times except when I keyed the mike.

Any other suggetions?

 

[bruceb58]

Re: VHF Transmit indicator says it's working, but is it?

I would bypass this AM/FM seperator. Are you trying to say there isn't a coax connector on the back of your VHF radio?

 

[coastalrichard]

Re: VHF Transmit indicator says it's working, but is it?

No Bruce, the coax goes from the antenae to the separator then on to the back of the VHF unit. I tried going straight from the antenae to the VHF and still nothing although I did here the NOAA forecast on 20.

 

[bruceb58]

Re: VHF Transmit indicator says it's working, but is it?

Is there a reason you just don't plug the antenna straight into the VHF radio?

 

[coastalrichard]

Re: VHF Transmit indicator says it's working, but is it?

No Bruce, the coax goes from the antenae to the separator then on to the back of the VHF unit. I tried going straight from the antenae to the VHF and still nothing although I did hear the NOAA forecast on 20.

Read this one again.

 

[NYBo]

Re: VHF Transmit indicator says it's working, but is it?

The transmitter in the radio may be fried from the bad antenna and/or potentially bad splitter.

 

[coastalrichard]

Re: VHF Transmit indicator says it's working, but is it?

The transmitter in the radio may be fried from the bad antenna and/or potentially bad splitter.

NYBo...that's precisely what I was learning after I searched the forums...no antenae=fried radio...I'll probably test with a loaner and, if proven, go get another VHF. Thanks!

 

[bruceb58]

Re: VHF Transmit indicator says it's working, but is it?

Read this one again.

Gotcha!