What is this gagdet please

[greggron]

This was on the boat when bought it (not the emergency VHF antenna, the other thing). I think it is attached to the back of the VHF. What is it please and what help is it to me?

 

[CPD]

I don't know but it looks like the power supply has been snipped .....

 

[Salty John]

Looks like a crude form of VSWR meter. It will tell you if your voltage standing wave ratio falls outside an acceptable level, caused by, perhaps, a corroded cable or connector, or crapped out aerial.

 

[Blue Drifter]

There is an example on eBay:

http://www.ebay.co.uk/itm/VTRONIX-MARINE-RADIO-VHF-AUTOMATIC-PERFORMANCE-MONITOR-/161150460717

 

[greggron]

Thank you that's very helpful. I don't think the supply has been snipped just doubled back. but I have never held the PTT button for 5 secs to see what it does because no instructions were around and I could not find any through google.

It might be useful!

 

[Salty John]

Modern radios usually have an antenna warning function that prevents you transmitting into an antenna system with too high a VSWR - you'll see 'antenna' flashing on the display. Check you're manual to see if you have such a function. That gadget looks a bit archaic to me.

 

[greggron]

Is there anyone out there with its instructions or how to interpret results (assuming it still works). Oh , and how to work it of course.

 

[Alpha22]

Interpreting is simple. It is basically an automatic SWR meter. You want maximum power forward and minimum reverse. That way all your RF is leaving the antenna and not reflecting back down the feeder and into the radio.

 

[nigelmercier]

I can't see a reason to fit such a thing unless you are having problems with the VHF...

 

[Alpha22]

Peace of mind - gadget geek?

 

[William_H]

I have to say if it were my new boat I would pull that device out. Keep it in case you want to reinstall to check a doubtful antenna. I think electronics in boats should be as minimal as possible and all working, reliable and with skipper familiar with them. The emrgency antenna OTOH is good to have. good luck olewill

 

[greggron]

Thanks for the responses. I have to conclude from the lack of 'I've got one' comeback that it's not a common piece of kit. I have emailed VTronix, (now Shakespeare) to see if they can throw any light. I wonder if they will respond...

 

[greggron]

Well respond they did. Seems that there are no remaining docs and the corporate memory on it has been lost too. I think it's coming out...

Thanks for everyone's help

 

[Twister_Ken]

I think it's coming out...

I'd see whether it works first, then put it on eBay if it does!

 

[rustybarge]

I'd see whether it works first, then put it on eBay if it does!

I think it's an impedance bridge meter used with SSB transmitter.
As you change the frequency you transmit on, the wave length changes, so the device changes the Resistance of the aerial to get maximum gain at that specific frequency.
With a manual meter you normally tune the impedence to get max gain.....