Help identifying antennas

[benzy]

I was reviewing some photos I took of the mast top and noticed I seem to have two antennas up there.

See below photo.



I think the thin one near the bottom is the VHF aerial?

What about the thicker black one?

Thanks

[JohnT]

Do you have an AIS receiver or transceiver on board?

[benzy]

Hi John, no I don’t.

I’ve tried tracing the cable back to its end but I get lost in some places I can’t access easily.

[JohnT]

I must admit, I have never seen an antenna quite like that (the lower one). Your black one should be your standard Marine VHF. If you are not the first owner, maybe the previous owner was a HAM and had a separate 2M radio on board with its stand alone antenna. I am also not sure what the white "butterfly" in the centre is.

Hopefully another member of the forum with better knowledge of that antenna will chip in. John.

[benzy]

Hi John,

To my eye the lower one looks a lot like this: http://shakespeare-ce.com/marine/pro...hfais-antenna/ which is a fairly standard 3dB mast top antenna. Thats why I thought that was the VHF (the “butterfly” is just a broken wind indication - one of those cheap plastic ones - so pretend it’s not there!).

Anyway, it’s still unclear...

[wayne.b]

Originally Posted by benzy

I was reviewing some photos I took of the mast top and noticed I seem to have two antennas up there.

See below photo.

Attachment 171764

I think the thin one near the bottom is the VHF aerial?

What about the thicker black one?

Thanks

===


The thicker black one is definitely a VHF antenna. The one on the bottom is probably for wifi but it's hard to say for sure. Does it have ethernet cable going to it or coax? If ethernet it's definitely wifi, if coax it might be for a cellphone amp.

[benzy]

Ok good to know.

It has a black round cable so I’m guessing it’s not ethernet. There’s no other kit onboard to suggest any kind of cell phone amp, but perhaps it was taken off when they the boat was sold.

[wayne.b]

Originally Posted by benzy

Ok good to know.

It has a black round cable so I’m guessing it’s not ethernet. There’s no other kit onboard to suggest any kind of cell phone amp, but perhaps it was taken off when they the boat was sold.

===


Outdoor ethernet cable could be black and round. Does it terminate in a coax connector like a PL259 or F-type? If not, it's probably ethernet.

[JohnT]

If that is an old cheap windex slipped over the whip of the bottom antenna, you will most probably find the PO had an AIS transceiver installed and removed the unit before selling, as that would then be a recognisable whip antenna that can be easily tuned two the two AIS frequencies. What type / make of MFD does the boat have? Do you have any contact with the PO? If so, ask the fellow! John.

[benzy]

I can’t trace it to its end without removing some woodwork unfortunately. So not going to do that at this stage.

The boat has an old Garmin GPS map 292. Honestly the kit on the boat was so old when we bought it I don’t feel like it would have been AIS. Previous owner sold due to health problems, etc, so is no longer sailing, so doubt he would have taken any AIS kit (unless to sell for cash). Anyway impossible to know really.

I will ask him but he wasnt the DIY type so Im guessing he wont know. When I have time I will try to trace the wire more accurately

[JohnT]

Try and get somebody in the telecom tech business to lend you a tone and probe - stick the tone onto the antenna whip and trace using the probe inside the boat. Anyway, seeing you have the mast dropped, whoever did that would have disconnected the cabling just inside your boat and you will find the terminated cables there to trace, which would mean you could use a standard multimeter to find which cable is which. Anyway, good luck with solving the problem - it should be easy if you are electrically or electronically a bit savvy. Otherwise, just ask the sparky who did the disconnect when dropping the mast - he or she should know! John.

[benzy]

Yeah might try that. This photo is from three years ago - mast is back up!

I can get to where it comes down through the deck, so I could disconnect it there and have a look. We are in the yard in a month or so for some other work so will investigate then.

Cheers

[Standbly]

The odd looking one could be a "windex -antenna". AV or VHF, no idea what those guys are up to now a day's. Could be just a worn windex with an anti-bird spike on it. Is there a wire coming out of the bottem?

Looks like a Windex antenna to me anyway. https://www.google.com/search?q=windex+antenna

[sy_gilana]

The top thick black one is a Philips Decca antenna.

[benzy]

Thanks sy_gilana. How can you tell?