Vhf

[RoyP]

Hi All,

I have fitted a VHf aerial to my van to monitor transmissions, I dont not seem to receive anything. I have checked the coax and it is connect and grounded accordingly. There is a join, but continuity is, 0 ohms, open circuit between signal wire and shield . This is a fibre twig, so not sure where to go from here.

I have a second handheld, which I have used to test, both seem ok. but as the transmit range was arms length, I would assume that the one attached to the twig, would receive anything.

thoughts greatly appreciated

[willk]

What channel are you testing on?

[Pikey Dave]

Do you have anything at all ? If you turn the squelch down, do you get white noise?

[RoyP]

White noise, just cant understand why no rec reception. I have another hand held which is identical and swapped them over, same result. I am thinking the the aerial is open, but as you can appreciate not able to test, it was new, which does not mean anything.

[smallribber]

Is there anyone transmitting

[Matt]

He used his 2nd handheld to transmit (I think).

[charliee]

how far from likely radio traffic are you. a typical handheld at 5 or 6watts has a max transmission range of 5-6 miles in a perfectly flat environment. With a higher aerial on your van roof this will increase a bit.
Do you get anything from any radio at your location? I suggest you may just be out of range?

[willk]

Originally Posted by Matt

He used his 2nd handheld to transmit (I think).

Yes, and if he's testing on a duplex channel, he won't receive anything. He seems cluey enough to know, but it's a common gotcha. I've heard ships do it

[Iron Dials]

Can I ask about the aerial? Some are pre-wired and sealed where co-ax connects to base of antenna.
Others require you to make the connection yourself with core exposed by a few mm and shield similarly formed outside insulation to make connection to threaded insert. Depending on condition, not sure if yours is new or used, this can corrode etc and might need to be remade.

Like this..
https://www.glomex.it/wp-content/upl...solderless.pdf

[RoyP]

OK thanks for all your replies,

I have two hand held radios apart from the larger unit in my boat. The idea is to fit a hand held in my camper to monitor the VHF traffic whilst parked. So, I fitted an aerial to said camper a run the coax accordingly. I acquired the correct adapter from the PL259 to SO21A aerial adapter.
I am about 10 miles from the Thames but can receive London VTS on 14, quite well, better on the boat at home and slightly less on the hand helds (Squelch lowered).
with both walkies on I can get reception on the one with the rubber twig, but not the one with the camper aerial. If I swap the units around the same happens.
If I transmit at close range they work OK, but I assume because of the proximity which is only meters from each other, I would expect nothing less.

IF I had a SWR meter I could check the xmtr at the aerial but a bit clueless on the reception side.

Not sure of which way to go, I may have to get another aerial to prove a point.

I hope I have explained

cheers RoyP

[RoyP]

Aerial is prewired fibre pole, all connections joints look ok, I have continuity of cable a from the joint, which have 259 type connectors. shield is earthed accordingly and isolated from the signal wire.

[Pikey Dave]

Originally Posted by RoyP

Aerial is prewired fibre pole, all connections joints look ok, I have continuity of cable a from the joint, which have 259 type connectors. shield is earthed accordingly and isolated from the signal wire.

To be fair, for receiving the antenna isn't critical, you should be able to pickup close by transmissions on a bit of old coathanger, even without an antenna plugged in if close enough. Have you tried un-plugging the aerial from the receiving set & keying the mike on the transmitting set from a meter or so away?