VHF probs - can anyone advise?

[KAL]

We lost our Vtronics/hawk winded just before Christmas, when the windex broke free in a gale and climbed the antenna, snapping it off.

Just had a new one fitted and went to test the VHF this afternoon. Called CG for a radio check - heard nothing. Tried again with same result.

Then sent a DSC call to the CG, to which they responded immediately, calling me back on Ch67 as usual. However, they could not hear me replying by voice.

I then called them by phone to let them know I was ok and only wanted a radio check. The officer told me that they had heard absolutely nothing on voice, but that the DSC came through fine.

I know nothing about the tech side of radio. The display tells me it's transmitting when I try a voice call, and I can hear the CG loud and clear but I don't seem able to transmit by voice.

Is this likely to be a simple connection problem with the new antenna, or might it be the set? Doesn't seem to make sense that I can receive, send digital signals, but a transmission at 25w can't be picked up by the CG who are only 3 miles from me.

Can anyone help with this one?

 

[prv]

I'm no expert, but it sounds more like a problem with the radio to me, not the aerial.

Pete

 

[VicS]

I'm no expert, but it sounds more like a problem with the radio to me, not the aerial.

Pete

Likewise

 

[David2452]

Get it checked by somebody with a meter to confirm where the fault lies, will only take ten minutes.

 

[garvellachs]

Hopefully you have an emergency aerial on board - try that instead. If not, someone local will have an old one they can lend maybe for a few minutes to see if it's the aerial or not. It won't do the radio much good if you transmit much at 25w without a good aerial connexion.

 

[Billjratt]

The thing that has changed is the aerial. A poor installation will cause the radio to shut down power when transmitting when it (the radio)senses reflected power - this stops it damaging it's own output stage. It will however, receive on a bent coathanger...
So check the aerial installation again.

 

[ProDave]

the CG was not being very helpful.

When he said he "heard nothing" did he hear a blank unmodulated carrier? could be a microphone problem?

Check it out with another known good radio in an adjacent boat, and yes check with a vswr / power meter to make sure it is transmitting properly.

 

[KAL]

the CG was not being very helpful.

When he said he "heard nothing" did he hear a blank unmodulated carrier? could be a microphone problem?

Check it out with another known good radio in an adjacent boat, and yes check with a vswr / power meter to make sure it is transmitting properly.

That's what I was wondering. He said he heard absolutely nothing, but yet the DSC went through.

The rigger who installed the new antenna does them all the time - he's supposed to be very good.

I have an emergency antenna - will rig that and try.

Never come across anyone with a VSWR meter - will investigate.

The emergency antenna test should tell whether it's the set or not.

Thanks all.

 

[emandvee44]

I am in the process of installing a new vtronix antenna with Hawk, and when I ordered the antenna I also purchased a test meter,
View attachment 40936
Easy to use and should pay for itself with one test (compared to the cost of a 'technician')
M.

 

[FulmarJeddo]

It may be a coincidence that the aerial has been changed. I had a no transmission problem on an old radio I had. I can't remember the make, but it had a plug and socket for the mike. One of the wires broke in the plug, possibly for the push to talk button. It was relatively simple to fix when I found it. That old radio didn't have DSC, but I would have thought if its transmitting DSC the radio transmitter is probably working. Check the mike cable for any sign of damage, does it feel as though the switch is operating ok as you push it? Mike cables can get abused, often stretched and always moving around.

I just read the original post again "The display tells me it's transmitting when I try a voice call" so its unlikely to be the PTT button, but could still be the mike or cable gone faulty.

 

[funk-an-bord.de]

VHF antenna

The reception of a DSC call is much better than voice.
So it might be a antenna problem (shortcut in the cable or disconnection).
Check with a ohm meter the cable.
Vtronic told me that the Rib antenna is DC open or up to recently they used a 10 kOhm resistor.
When the OhmMeter is looking into the cable and you see a short cut, than check the connectors.
If you see a open circuit, theat result will not help to isolate the fault. You will have to open the connector and see if the soldering and braid connection is ok.
Best, Wilhelm

 

[Uricanejack]

We lost our Vtronics/hawk winded just before Christmas, when the windex broke free in a gale and climbed the antenna, snapping it off.

Just had a new one fitted and went to test the VHF this afternoon. Called CG for a radio check - heard nothing. Tried again with same result.

Then sent a DSC call to the CG, to which they responded immediately, calling me back on Ch67 as usual. However, they could not hear me replying by voice.

I then called them by phone to let them know I was ok and only wanted a radio check. The officer told me that they had heard absolutely nothing on voice, but that the DSC came through fine.

I know nothing about the tech side of radio. The display tells me it's transmitting when I try a voice call, and I can hear the CG loud and clear but I don't seem able to transmit by voice.

Is this likely to be a simple connection problem with the new antenna, or might it be the set? Doesn't seem to make sense that I can receive, send digital signals, but a transmission at 25w can't be picked up by the CG who are only 3 miles from me.

Can anyone help with this one?

DSC radios have two antennas. One for regular and one for the dsc . Most lilky problem with one of your antena connections. Change them try again. Your regular may work and dsc function won't. Probably damp or loos connection some where. If no difference when antennas changed you have a radoi problem
If cg can hear your voice on dsc its not a mic problem or transmit button.

 

[KAL]

The reception of a DSC call is much better than voice.
So it might be a antenna problem (shortcut in the cable or disconnection).
Check with a ohm meter the cable.
Vtronic told me that the Rib antenna is DC open or up to recently they used a 10 kOhm resistor.
When the OhmMeter is looking into the cable and you see a short cut, than check the connectors.
If you see a open circuit, theat result will not help to isolate the fault. You will have to open the connector and see if the soldering and braid connection is ok.
Best, Wilhelm

Hi Wilhelm. Do you mean test for continuity between the core and the sheath of the coaxial cable?

EmmandVee - thanks for that - approx how much was the meter and, more importantly, does it come with decent instructions for a non-specialist?

 

[KAL]

DSC radios have two antennas. One for regular and one for the dsc . Most lilky problem with one of your antenatal connections. Change them try again. Your regular may work and dsc function won't. Probably damp or loos connection some where. If no difference when antennas changed you have a radoi problem

Only seems to have one antenna cable in the rear of the set!

 

[SimonFa]

DSC radios have two antennas. One for regular and one for the dsc . Most lilky problem with one of your antena connections. Change them try again. Your regular may work and dsc function won't. Probably damp or loos connection some where. If no difference when antennas changed you have a radoi problem
If cg can hear your voice on dsc its not a mic problem or transmit button.

Eh? I think you mean two power amplifiers?

 

[SimonFa]

Hi Wilhelm. Do you mean test for continuity between the core and the sheath of the coaxial cable?

EmmandVee - thanks for that - approx how much was the meter and, more importantly, does it come with decent instructions for a non-specialist?

Get something like this, very useful all round and simple to use. http://www.lyco.co.uk/faithfull-mul...ampaign=base&gclid=COGqlZ6DrL0CFc_MtAodlj4AWA


And very simple to use: https://www.google.co.uk/search?q=h...&channel=sb&gfe_rd=cr&ei=05cwU9iwPIjY8geL64AQ

 

[Sarum 28]

Hi Wilhelm. Do you mean test for continuity between the core and the sheath of the coaxial cable?

Yes, that would isolate a man made short curcuit.
,,,,DSC radios have two antennas. One for regular and one for the dsc ...
The verry old ones as ICOM M503 have a separate antenna for reception of DSC, but a common antenna for emission of voice AND DSC.
Radios since 2007 have a common antenna for DSC and voice.
Wilhelm

 

[KAL]

Get something like this, very useful all round and simple to use. http://www.lyco.co.uk/faithfull-mul...ampaign=base&gclid=COGqlZ6DrL0CFc_MtAodlj4AWA


And very simple to use: https://www.google.co.uk/search?q=h...&channel=sb&gfe_rd=cr&ei=05cwU9iwPIjY8geL64AQ

Thanks SimonFa, I appreciate your very useful links, although I already have a multimeter and use it all the time. It's the VSWR meter I meant.

 

[KAL]

Yes, that would isolate a man made short curcuit.
,,,,DSC radios have two antennas. One for regular and one for the dsc ...
The verry old ones as ICOM M503 have a separate antenna for reception of DSC, but a common antenna for emission of voice AND DSC.
Radios since 2007 have a common antenna for DSC and voice.
Wilhelm

Thanks, that clears that one up. welcome to the forum by the way.

 

[misterg]

That's what I was wondering. He said he heard absolutely nothing, but yet the DSC went through.

I had a DSC alert go through from a VHF on a dummy load at home, about 20 miles from their nearest aerial (but line of sight). They also managed to transmit with enough power for the set to receive voice, too.

I doubt that a short in the aerial coax would stop DSC getting out, but bet it would stop voice.