VHF declining performance

[VicMallows]

These are not cheap!

You can certainly say that again

 

[TonyBuckley]

Still learning! R8u vs R8x. Think I have the 10.3mm stuff which could be RG213. That fitting won't take 10.3mm.

Beginning to despair lol. Perhaps I will have to try and solder in single figure centigrades and a chilling breeze - can't see that working. This must be a fairly common issue yet no easy answers.

 

[prv]

Perhaps I will have to try and solder in single figure centigrades and a chilling breeze - can't see that working.

I was soldering together the wiring for my new deck lights on the mast, at the weekend. Managed ok, but I did have to turn up the gas on my Iroda 120 from its usual mid-position up to max:

Pete

 

[ShinyShoe]

@ShinyShoe

That's interesting, not seen the Ship Tracking DSC log before. Surprised how few calls are on it.

Me too. Although I think their mast / set up is not optimally configured for it because it seems to get a fairly narrow range of transmissions.

Re testing to self, my Skanti radio can do it, with options of internal path or external path (unfortunately it doesn't seem to have facility to do a test call or a position request to another station, the self test is all it can do). Also in the DSC log I note:

Self testing sounds flawed to me! It sounds like it isn't actually transmitting out the aerial which in your case is what you want to test. I just don't see how it would work otherwise.

MCS ANNEKE,2CSG7-G (safety) from MCS ANNEKE,2CSG7-G test ACK [13-11-21 07:00:20]
MCS ANNEKE,2CSG7-G (safety) from MCS ANNEKE,2CSG7-G test ACK [13-11-21 07:00:30]
MCS ANNEKE,2CSG7-G (safety) from MCS ANNEKE,2CSG7-G test ACK [13-11-21 07:00:35]
MCS ANNEKE,2CSG7-G (safety) from MCS ANNEKE,2CSG7-G test ACK [13-11-21 07:00:41]

Isn't that a test to self? Maybe I'm misunderstanding it.

That is a test. Curiously they are all acknowledgements, no original call? Same happens daily. Its based in Southampton - so possible they request comes from a unit thats just badly mounted and slightly out of range.
Bear in mind commercial shipping has Cat A Kit, your pleasure craft with have Cat D so they can do slightly different things.
My most likely explanation would be that the boat has two DSC sets with the same MMSI number. That may seem odd but large vessels will often have redundancy in their electronics. You wouldn't really want to be berthing a super tanker and loose comms with your tug etc. And in addition on a large bridge you don't want to walk 30ft to the radio so you have a radio on the port and starboard.

The MCS ANNEKE is not that big: http://www.maritimecraft.co.uk/index.php?option=com_content&view=article&id=38&Itemid=25 don't know the rules on how big you need to be to carry redundant equipment but would have thought bigger than that. But look back at the picture on the link there are a lot of aerials on the ,mast/roof of the wheelhouse. I count at least 6 aerials... so are there 4 or 5 DSC sets? Seems excessive but if you want to listen to 9,13,16,11,12 plus any private channels maybe they need to rather than using scan?

 

[st599]

OP here - I am not convinced it needs new coax. It is much thicker than I have seen before and looks in good condition - my problem is one connector that has had drips collecting over a few months. Yes it has oxidised but looks like it can be cleaned. I could be wrong . More concerned about the unit being fried. Can't find if that unit has any protection.

I will clean and see if I can get a good signal to Solent Coastguard on CH67 from Haslar. If not, then obviously something wrong.

How would one test if the VHF is working optimally? A call to Solent CG has never been a prob before but it is not that far.

Problem is you're relying on skin effect. Any corrosion and you're knackered.

 

[Plevier]

Self testing sounds flawed to me! It sounds like it isn't actually transmitting out the aerial which in your case is what you want to test. I just don't see how it would work otherwise.

I can see your point, and I don't have enough technical knowledge of the Skanti to explain (its documentation is appalling) but it does include this internal or external path selection on a test call. I don't see what else external can mean. Is there some sort of default MMSI number it could be calling for a test response I wonder? There is a very short delay before the test signal is "received". It doesn't just say test OK or anything like that, it displays it exactly the same as a normal station to station DSC call as far as I recall.