VHF antenna connection

[dewshi]

What is the connection I need to solder on the end of an RG58 cable running to the top of the mast to join to an antenna? For example, V-Tronix whipflex.

Do most antennas plug in with a pl259 male fitting at the base, meaning I have to use a FEMALE so239 socket on the cable?

I know this sounds backwards (!) but I need to repair the cable baked in to my wooden mast before I select an antennae, and I can’t find this info on any of the ones I’ve looked at.

Thanks for any info.

 

[Boathook]

The connection on to the aerial can vary as to the make. The cables do fail due to water ingress and I had to replace my cable for that reason.
Possibly not you want to hear.
I have seen cables run up the shrouds / stays on wooden masts and nearly did that on my metal mast as a temp job as I was struggling to draw out the old cable.

 

[dewshi]

The connection on to the aerial can vary as to the make. The cables do fail due to water ingress and I had to replace my cable for that reason.
Possibly not you want to hear.
I have seen cables run up the shrouds / stays on wooden masts and nearly did that on my metal mast as a temp job as I was struggling to draw out the old cable.

@Boathook OK thx. I guess I’d better test the cable first. It’s pretty old and it’s not coming out of the mast any time soon as you can see from this pic;

 

[Commercial Dave]

If it's this:



I am certain that is not a PL259 or in fact any type of standard RF connector. According to the internet:

The Whipflex features the popular V-Tronix solderless connector system...

 

[William_H]

When selecting a new antenna do be aware that with a wooden mast you need an antenna that does not need a ground plane. ie one made for GRP cabin top mobo. Many antenna rely on the connection to the ali mast as the ground plane so not best for wooden mast. Also suggest you take back insulation on existing cable as you may find corrosion on wire so far back that you can not reliably get a connection. So need a new cable. ol'will

 

[dewshi]

When selecting a new antenna do be aware that with a wooden mast you need an antenna that does not need a ground plane. ie one made for GRP cabin top mobo. Many antenna rely on the connection to the ali mast as the ground plane so not best for wooden mast. Also suggest you take back insulation on existing cable as you may find corrosion on wire so far back that you can not reliably get a connection. So need a new cable. ol'will

@William_H Thanks for the tip about a compatible antenna. I wasn't aware of ground plane.

There's about 20cm of cable out the top, so hopefully it's not all coroded. I think I will have to jump it anyway to reach the antenna. Which means I can cut the cable supplied with whatever antenna to a short length and solder on a PL259.

That plug/socket connection would sit inside the stainless steel cone at the top. Is this an issue for ground or interference? Pic here:

 

[William_H]

Ah that stainless steel cone will work as a ground plane assuming it is longer than 17 inches. (1/4 wavelength) and assuming the antenna is on top of the cone. Next to it not so good. ol'will

 

[dewshi]

Ah that stainless steel cone will work as a ground plane assuming it is longer than 17 inches. (1/4 wavelength) and assuming the antenna is on top of the cone. Next to it not so good. ol'will

@William_H Yes it’s 20”. But I am still figuring how to mount it, because the anchor light sits on the top.

Presumably if it’s to the side, the metal cone blocks the signal transmission. Is that correct?

Maybe it can go lower, adjacent only to wood ??

 

[st599]

@William_H Yes it’s 20”. But I am still figuring how to mount it, because the anchor light sits on the top.

Presumably if it’s to the side, the metal cone blocks the signal transmission. Is that correct?

Maybe it can go lower, adjacent only to wood ??

Not only blocks it, but completely changes the radiation pattern and if very close puts enough power back down the coax to overload the receiver.

 

[dewshi]

Not only blocks it, but completely changes the radiation pattern and if very close puts enough power back down the coax to overload the receiver.

Yikes !

 

[st599]

Think of a TV "aerial" antenna, it has one element attached to the coax, all the others are not connected, their position just changes the radiation pattern making it highly directional.

Same thing with VHF antennas. Place metal nearby and they lose their omnidirectional pattern.

 

[William_H]

Yes the base of the antenna should be at the top of the cone. The mast head light could perhaps be mounted forward of that on a flat plate. ol'will

 

[dewshi]

@William_H @st599 Thanks for the advice