VHF transmission but no reception

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kalanka

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I have a Navman DSC 7100 radio, about 8 years old, internally mounted inside a dry boat and previously reliable. Set appears in good condition and is connected to a good quality antenna. On my first outing this year I noticed that the Squelch adjustment produced no noice and that no audible signal was being received from external stations. Transmission and displays appear to be normal but there is no reception at all. Volume is turned up!

Navico were less than helpful...

Connected an external speaker - still no audible reception

Checked the internal menu - confirmed that internal speaker was enabled.

Cleaned antenna connection - no effect.

Checked and jiggled wiring connections to set - no evident problems.

Is this the sort of problem that can be repaired or do I need to buy a replacement?

If a replacement, what do people recommend?
 
Does it show signs of being 'busy' when another station is transmitting?
There's often an 'RX' or something on the display?

I assume you are on a simplex channel?
I assume you have tested on 16 with a handheld or friend's boat nice and close?
It's possible your aerial is bad and the other person receiving your signal has a great receiver but not great transmit power.
So, I'd try a different aerial if possible, doesn't need to be high up, test with a handheld 50m away.


It's a difficult call whether to pay for an attempt at repairing it. It might be something very easy to fix, it might not.
I can see it would easily eat a big chunk of theprice of a new one, which would come with a warranty.
And once something has let me down, I don't want to rely on it in future without a good reason to believe the same failure won't recur, or some other part of equal age and quality.

It may have been zapped by lightning, which wouldn't be the maker's fault of course.
 
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kalanka said:
Transmission and displays appear to be normal but there is no reception at all. Volume is turned up!
Click to expand...
My first question would be to ask how you know your TX is Ok? 25W blasted through a crappy cable/antenna/whatever might still 'work' for a test over very short range (to a handheld?), Receiving a much weaker signal could, however, be blocked. That said, if you wind the squelch to zero I'd expect something to happen... :(

I'm afraid that commercial repair of this sort of gear just isn't economically viable (IMHO).
If you were to replace it, I'd have no hesitation to point you at Standard Horizon. All my radios are made by them, their after-sales is superb and the gear seems to go on and on. Searching on here will confirm their reputation to be pretty good.
 
I'd agree with TernVI that you'd probably be better off in the long run putting the potential repair cost towards a new radio.

Standard Horizon is a good brand. The GX1400GPS has built-in GPS receiver for £150, or the GX2200 has built-in GPS plus built-in AIS receiver with a simple display, for £300.
 
Thanks for the comment. I lean strongly towards buying an SH1400 set but am not currently on the boat. When back I will do a test call to the Stornoway CG and listen to their answer (or not) on a handheld. If the indication is the antenna then will replace. It is a good quality Metz antenna and only 8 years old. My suspicion is that the internal circuitry of the existing set is shot. Not much confidence in modern consumer electronics - impressive but unreliable.
 
Can you try the set on another boat with known good transmission/reception? Another vote for SH if you replace, I had the GX2200e on my last boat with AIS receive, excellent set.
 
kalanka said:
I have a Navman DSC 7100 radio, about 8 years old, internally mounted inside a dry boat and previously reliable. Set appears in good condition and is connected to a good quality antenna. On my first outing this year I noticed that the Squelch adjustment produced no noice and that no audible signal was being received from external stations. Transmission and displays appear to be normal but there is no reception at all. Volume is turned up!

Navico were less than helpful...

Connected an external speaker - still no audible reception

Checked the internal menu - confirmed that internal speaker was enabled.

Cleaned antenna connection - no effect.

Checked and jiggled wiring connections to set - no evident problems.

Is this the sort of problem that can be repaired or do I need to buy a replacement?

If a replacement, what do people recommend?
Click to expand...
A long shot. I had a problem with my vhf (different make) transmit was fine but reception was very weak with a lot of background mush noise. The problem was a 12volt usb phone charger!

Www.solocoastalsailing.co.uk
 
Thanks for your comments. I managed to get the antenna transmitting a signal to a hand held over 100 m away so decided the set was the problem. Replaced with a SH 1400. Works fine. Nice to not have to mess about connecting the set to a separate GPS.
 
I had a Raymarine 49E VHF that developed the fault of transmitting but not receiving. Or at least not giving any audio output when receiving, as there could have been a signal flashing round its innards but not getting put out through the speaker. I tested the antenna etc. In the end I binned it and bought an Icom.

As an aside, I wouldn't be surprised if many Solent VHFs wear out through the number of radio checks they are made to do. Maybe there's a chip in there that goes on strike after the first thousand. Not that kalanka's VHF has that problem because our Scottish friends probably have more sense than paying for the electricty to waste on radio checks
 
Thanks! As a Yorkshireman long domiciled in Scotland that made me laugh! Actually, I was almost embarrassed to radio Stornoway CG to check that the new installation was functional... Have never understood this compulsion for daily radio checks. I rather go with Tilman - Let each herring hang by its own tail
 
I replaced my radio only to find the aerial lead had worn through at the masthead. The symptoms on both radios were similar to yours. I would buy a spare or emergency aerial first and try that. You don’t need to fully install to test it. Just tape it to the boat hook and tie that onto a guard rail. Then test it from out at sea in an area where you can use a mobile phone on an emergency.
 
kalanka said:
Have never understood this compulsion for daily radio checks. I rather go with Tilman - Let each herring hang by its own tail
Click to expand...
The are not compulsory, but it's good to know that your radio is working.

Having been a member of a Mountain Rescue Team in an area with lots of black spots trying to save a life was made more difficult without Comms.
 
I guess my somewhat laid-back attitude to radio checks is down to factors that don't apply to everyone:
- I scarcely use the thing apart from listening to weather and calling up the occasional British yacht I pass at sea
- the occasional routine call (eg to other yachts) satisfies me that it's working on transmit, and listening out on ch 16 satisfies me several timnes a day that the receiver's working
- with a handheld VHF, mobile phone and PLB (not to mention some flares) as backup it wouldn't be a disaster if the main VHF packed up.

if the mast has been out over the winter though I do try to remember to give it a test by calling another yacht at a good distance.

When I used to fly a light aircraft, a radio check was a standard procedure before every flight (or if flying from a farm as soon as airborne) because contact with air traffic control is mandatory in some circumstances and a non-working radio could be dangerous, specially if you don't know it's not working.
 
snowbird30ds said:
I had the same radio and it proved to be most unreliable, I'd bin it and buy SH/Icom instead and have confidence in it working, both have very good service too.
The navman was sold under a few different badges.
Click to expand...
My Icom is coming up to 25 yrs old, removed it from my previous boat i installed it in. No DSC but not really missing what i nave never had
 
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