VHF radio issue?

[Craig Cook]

I was down sitting in the boat this weekend in the rain and thought I would put the weather radio on to check the forecast. I turned on the Icom unit that was OEM in 2008 (low end unit) and switched to the weather band. It came right up but about 30 seconds into the broadcast started to get faint and then very shortly nothing but background noise. I checked other weather channels, nothing. I switched over to 16, nothing, although it was a downpour and there were no boats out on the bay I could see.

Went back down on Sunday to blue sky but winds to 30 knts., tried the unit again. Same weather channel broadcast but it was fine for a few minutes, eventually got faint and stopped. I'm already looking at a new radio but it seems odd that a lightly used radio would go bad?

Thoughts?

 

[Ron20324]

Parts will age, even if not used. IIRC, I believe capacitors are the worst, as they should be "exercised" to maintain them.

 

[Brian D]

This is very interesting. Wonder if your receiver frontend is having heat issues. Granted it may not seem hot to us, but some components change their values when they get hot.

Let's run a test. Next time you are at the boat, turn the radio on to WX channel. If you are receiving it just fine, turn off the radio. Disconnect the antenna and turn the radio back on. Let it run for a few minutes then reconnect the antenna. If the signal is gone then yeah, radio is done. However, if you still hear WX, wait a few more minutes and see if it goes away. I don't think it is antenna issue. But I am curious to see if the signal goes away when the radio is on but no antenna connected.

 

[Craig Cook]

I can do the test for sure, so you are saying that it's "possible" that the masthead antenna could have issues?

 

[SG]

Hook-up a temp antenna and see what happens. I'd make sure it isn't a bad connection to the antenna.

Do you have a dual use antenna (e.g.., FM radio plus VHF; or AIS plus VHF plus; etc.)?

DO NOT ATTEMPT TO BROADCAST WITHOUT AN ANTENNA CONNECTED! I wouldn't attempt to broadcast until you make sure you don't have a bad antenna.

 

[Craig Cook]

No, this is a typical Shakespear SS whip, base loaded, mounted at the mast head. There is nothing but the VHF attached. I would not hit the mike button without some sort of antenna attached, thanks for the warning though.

 

[SG]

Depending on what's going on, even if the antenna is "connected" -- I"d counsel you to assume it's not there if there is discontinuity in our connection to -- or it, itself.

 

[Don S/V ILLusion]

A bad antenna or antenna connection would not cause the progressive fading described.
A simple way to eliminate the antenna system is to connect it (the antenna) to handheld.
Conversely, connecting a different antenna or a short wire to the center conductor of the PL258 will demonstrate if it is the radio.

It may be a thermal problem due to a bad internal component heating inside the radio.

 

[Brian D]

I can do the test for sure, so you are saying that it's "possible" that the masthead antenna could have issues?

It is "possible" but I don't think that is the issue. More than likely the radio is on its very last leg.

 

[Jim 5757]

FWIW I don't believe the antenna will change it's reception over time especially if you're just receiving and not transmitting.

 

[bawlmer]

Back in the day I actually used to fix two way radios. It sounds to me like you have a problem inside the radio. A component or internal connection has gone defective. An antenna or DC power issue would not cause the symptoms you describe. In this day and age it make more economic sense to replace the radio rather than have it fixed.

 

[Ken Cross]

Put it in the frige for a few hours, then turn it on and see if it lasts longer. That will verify if it's a heat issue, but most handhelds aren't usually worth fixing.

Now you get a chance to buy one with built-in GPS and DSC. They they're cheap.

Ken

 

[Captain Larry-DH]

I agree replacing the radio is your best option, and 9 years is not a bad life from an electronic device that's been out in a boat (without heating and air conditioning) year round.
Also, if you own a smart phone I'm surprised you still listen to marine VHF weather broadcasts (unless out of cellular coverage range). My wife and I were just having the conversation last night "Remember when we used to try to get weather info on the VHF, and struggling to pay attention to the droning voice to get the weather..... and we'd listen for 5 minutes while it goes through all the other information, and .... what was that again?"

 

[gettinthere]

Hmmm. My 3 year old SH GX 2150 is doing this, altho it is taking more like 12 or more hours to fade out completely.

 

[Craig Cook]

it was the radio. I have replaced it with a Standard Horizon Galaxy 1300 which turned out to be smaller than the old radio. That 15 minute swap turned into a 2+ hour project but it's installed and working. I sat for another hour with the user manuals from both the radio and chartplotter and still can't get them to talk. The radio had very specific instructions on how to set up the chartplotter as the talker, unfortunately the chartplotter did not have the menu items for setting baud rate and a few other radio specific instructions. I walked away after that, perhaps next weekend, if it ever stops raining here and the wind drops below 30knts I'll try again. The boat was rockin' at the dock yesterday!

 

[Captain Larry-DH]

it was the radio. I have replaced it with a Standard Horizon Galaxy 1300 which turned out to be smaller than the old radio. That 15 minute swap turned into a 2+ hour project but it's installed and working. I sat for another hour with the user manuals from both the radio and chartplotter and still can't get them to talk. The radio had very specific instructions on how to set up the chartplotter as the talker, unfortunately the chartplotter did not have the menu items for setting baud rate and a few other radio specific instructions. I walked away after that, perhaps next weekend, if it ever stops raining here and the wind drops below 30knts I'll try again. The boat was rockin' at the dock yesterday!

Hi Craig --
I can help you with that. Please post links to the radio and CP manuals, or just give me the CP model numbers and I can tell you how to hook them up. Probably just a wiring issue and (maybe) no menu setup needed.

 

[Craig Cook]

Any help would be appreciated Larry. The radio is a Standard Horizon GX1300B, the chartplotter is a Garmin GPS Map 547xs. I currently have the GPS talking via the NEMA 0183 output and the radio listening on a NEMA 0183 input. The radio specifies that the GPS Baud rate should be set to 4800 however I can't find any reference to setting that in either the Garmin manual or menu. I did use the radio manual reference for NEMA sentences it understands and made sure those were all turned on in the CP.

 

[Ken Cross]

it was the radio. I have replaced it with a Standard Horizon Galaxy 1300 which turned out to be smaller than the old radio. That 15 minute swap turned into a 2+ hour project but it's installed and working. I sat for another hour with the user manuals from both the radio and chartplotter and still can't get them to talk. The radio had very specific instructions on how to set up the chartplotter as the talker, unfortunately the chartplotter did not have the menu items for setting baud rate and a few other radio specific instructions. I walked away after that, perhaps next weekend, if it ever stops raining here and the wind drops below 30knts I'll try again. The boat was rockin' at the dock yesterday!

It sounds

Any help would be appreciated Larry. The radio is a Standard Horizon GX1300B, the chartplotter is a Garmin GPS Map 547xs. I currently have the GPS talking via the NEMA 0183 output and the radio listening on a NEMA 0183 input. The radio specifies that the GPS Baud rate should be set to 4800 however I can't find any reference to setting that in either the Garmin manual or menu. I did use the radio manual reference for NEMA sentences it understands and made sure those were all turned on in the CP.

Ground the negative leg. This is a common thing with Garmin and the manuals don't tell you that.

Ken

 

[Captain Larry-DH]

References: Page 16 (section 6.4) of the GX1300 manual, and Pages 3 and 4 of the Garmin Installation Instructions http://static.garmin.com/pumac/GPS-echoMAP_500-700-50-70_INST_EN-US.pdf
The Garmin manual is confusing because of the terminology it uses. For example, it says the Garmin function is TX and corresponds to the "NMEA device wire function" of Receive + . So is it send or receive? It's send, and must be connected to the OTHER device's receive:
Pin 3 is Black or shield and ground (or "-") it is used as a reference level for the signal and must be connected to the radio's GREEN and BROWN NMEA "-". If you have both black and shield wires from the GPS, connect them together with the Green and Brown from the radio. (Don't worry that the radio has a separate green and brown for input and output "minus", they are the same, because all "plus" signals reference "signal ground" which should be the same as "common ground" and not "float" at different voltages. The Garmin manual has a note that says the two port grounds don't need to be combined, but it doesn't say they shouldn't be, and it will simplify/stabilize the installation if you do connect them all together.)
Pin 4 is the blue wire and is Garmin Port 1 Transmit. It should be connected to the Yellow GPS Receive wire from the radio. This will enable the radio to send position info.
Pin 5 is the Brown wire and is Port 1 receive. It should be connected to the White DSC Send wire from the radio. This should enable the Garmin CP to display position info sent by other senders of DSC distress calls.
It gets interesting, because the Garmin CP has two NMEA 0183 ports, but the GX1300 radio has one GPS port. So the GX1300 radio will receive GPS info but send DSC info to the CP, all on one port. You will need to assign this through software in the CP. This is all the time I have tonight and haven't looked up the Garmin settings you need. But I hope this helps.

 

[SG]

That's just plug and play, Larry? Who would have easily noodled through that?
Thanks, I now have figured out why something never worked when Infinally called professional help for a NEMA 0183 connection a few years ago!