Standard Horizon radio issue...

PeppaPig

PeppaPig

Well-Known Member
Joined
18 Nov 2007
Messages
101
Location
UK
Visit site
I have a GX 1500e DSC radio. When plugged ino the mains at the marina I can transmit and receive fine. Once on battery at sea after a short while I find I no longer obtain a "Squelch" no matter how much I adjust the squelch control and I cannot hear anything in receive. I can still transmit, but even trying to contact with the hand held in close proximity does not get through.

Have you come across this issue before? This has only recently arisen and I suspect the batteries may have something to do with the problem, but even switching banks and turning off other devices does not rectify the problem. Once back in the marina it can still take a little while before the radio receives once again. The problem remains even when under engine power on our sailing vessel.

Any guidance would be appreciated.
 
I only checked on the main panel around 12v, but when the engine is on the levels look fine in any case 12.5+. It seems odd that the receive should fail first on a lowering voltage rather than thetransmit which i would have thought drew a lot more power...
 
I agree - the voltage is probably a red herring ... as you say, you should be able to receive with no problem - its the transmit that would die out first ...

I have a sneaking suspicion that this is an earthing issue.... I assume the shorepower which charges the batteries has an earth that is linked through to the battery -ve.

I'm not "up on" antennas and how they work, but I know there is a signal and an earth connection.

Assuming you have nothing in the antenna line like an AM/FM splitter or an AIS splitter .... can I make a suggestion - if you have an emergency antenna or a seperate AIS antenna, you could plug the VHF into this and test. You can do this in the marina by unplugging the shorepower but not going anywhere!!

It is probably worth getting a multimeter in at the VHF powersupply whilst doing this - dirty connections can kill power available very quickly and it would be good to rule this out.

A visual inspection of the antenna connectors should also be done - it could be that the shroud has become unattached from the connector, (I could be talking bollox here, but this is just a guess) the antenna could be making a ground connection through the rigging to an anode and looping back via the shorepower connection - either in the gubbins on your boat or via the marina structure.
 
Thats a thought - we have nothing extra on the antenna, and i do have an emergency one too - I went throught the obvious cxns for the fittings - thru deck/ back of unit etc just to make sure, but unplugging and doing the test you suggest sounds like a plan in a wet Brighton Marina today! If so I will then need to sort the earthing issue... In the meantime I am checking the fluid levels in the batteries ( about time!) as well, but I don't have a hydrometer for proper testing ( they are lead acid!!) . All that and a few leaky windows......
 
It sounds to me that the voltage is dropping too low. It could be that the circuitry is designed to carry on transmitting even on a low voltage, the transmission may not be going far. Where is your radio power lead connected to? I seem to recall being told on a radio course that the radio should be connected directly to the battery, or main battery isolator. You can get quite a voltage drop in the boats wiring. I tried to run a lap top through an inverter plugged into a socket at the chart table. There was insufficient power. With the inverter connected directly to the battery no problem. I can't see the logic in it being an aerial problem if the radio is working when on mains or the engine is running. In both cases the batteries are being charged by a higher voltage being applied. Check the voltage at the radio fuse with the radio on, not easy I know, but I wouldn't mind betting the voltage will be well below 12v. Open circuit with the radio unplugged you may well see 12v.
 
No - if you re-read the OP it doesn't work when the engine is running ..... but it does on shorepower ... a while after he is back in the marina ... bit of a funny one ... unless the engine isn't charging the batteries .... which is another possibility.
 
It sounds like batteries failing to hold a charge rather than anything to do with the radio or antenna. Do your lights dim after a period away from shore power?
 
I have just recreated the problem while alongside. I have disconnected shorepower, put on the usual instruments I would have running and then monitored the situation. At the back of the set is a plug/socket connection for th power, unplugging this and checking the volatge initially showed about 12.9v - very similar to that of the domestic battery (about 12.94v). after 15mins the battery had dropped to 12.5v (same reading at radio effectively) at this point the speaker on the radio crackled a little and when I went to adjust the squelch the sound faded away and now there is no squelch. A techie from Std Horiz suggested the voltage drop scenario, and reckoned the set needed at least 11.75v to function correctly, so I imagine 12.5v should be plenty - so I am also waiting to hear ay pearls of wisdom from them. I may just get a new domestic battery anyway, as a pb-acid one isnt too dear for 110amp/hr, and that would cover those issues......

Salty John - lights do dip a little but no more than I might suspect after a day or 2.
 
I have now reconnected shorepower, turned on the charger, and get 13.4v at the batteries and at the radio terminals. IF this was a voltage effect, why doesnt the radio immediately start wroking correctly as I still have no squelch??? and therefore no reception. I anticipate that in a few minutes it will start working again. ALSO if this wasan earthing issue why doesntthe set start working straight away once on shorepower....hmmmm....
 
Do you get 13.4 volts at the radio terminals when the radio is on load (connected to the battery) or do you measure it with the plug disconnected from the radio?

Alan.
 
That is with the terminals unplugged - i.e. no load. The connector clip is 5cm from the back of the radio and that is where i have taken the readings - I guess I have to find a way of measuring the voltage while it is operatiional. BTW I have also rigged up the emergency vhf antenna and get the same results as someone suggested an earth fault earlier...
 
I think, as Saltyjohn suggested, that you have a duff battery. Although in your original post you did say that you "had swapped battery banks" and fault was the same?? I would suggest to do the same test as you have just done with shore power and disconnect the domestic batteries completely ................ i.e. use only alternative battery bank (engine start battery??) and shore power and see if the situation changes.

Also on shore power, when your battery(ies) are charged up you should be seeing around 13.4 volts. The quickest way of fault finding would be to replace the "suspect" battery at least temporarily (borrowed from a neighbour/mate?) and see if the situation changes.

Alan.
 
yup - concur - glad you've done the antenna test - it is quick and easy to do (should be if it is an emergency antenna!!)

So looks like you need a closer look at your wiring ad batteries!!
 
You must log in or register to reply here.

Share this page

Top