Converter from SO239 to 1" 14-TPI antenna mount?

[nigelmercier]

Has anyone seen a converter from SO239 to a 1" 14-TPI antenna mount?

Salty John does one, http://www.saltyjohn.co.uk/metzmantaaccessories.htm that looks like this:

However, I was looking for something a bit neater: a PL259 plug on the end of a tube, with a 1" 14-TPI antenna mount the other end.

 

[lw395]

The pl259 plug itself screws down onto a rubber gasket, to seal it.
So it's not really mechanically firm enough to mount a decent antenna on, that's better done with a backnut onto a bracket as above.

 

[nigelmercier]

It seems Salty John does exactly what I want, so I've now got a spare antenna!
http://www.saltyjohn.co.uk/alpha_one_vhf_antenna_aerial.htm

I've been thinking though, 1" OD at 14 TPI, isn't that 3/4" BSP?

 

[rogerthebodger]

It seems Salty John does exactly what I want, so I've now got a spare antenna!
http://www.saltyjohn.co.uk/alpha_one_vhf_antenna_aerial.htm

I've been thinking though, 1" OD at 14 TPI, isn't that 3/4" BSP?

Not quite the same both 14 TPI but 3/4" BSP is 1.041 " O/D. A 3/4" socket will for on to a 1" 14tpi male fitting but a 3/4" nipple will be very tight in a 1" 14TPI female fitting.

Been there got the t shirt etc.

 

[nigelmercier]

A 3/4" [BSP] socket will [fit] on to a 1" 14tpi male fitting ...

So I could have possibly made the adaptor using a brass tap connector, a bit of tube, and a PL259...

 

[rogerthebodger]

Yes I blanked off a spare 1 " fitting with a 3/4" stainless socket and a plug.

I would weld a PL259 nut on top of the socket but thats just me as I have tig welding fitting.

Do yo know the spec of the PL259 thread ?

It seems the thread size is 5/8" 24 TPI

http://www.amphenolrf.com/products/uhf.asp?N=0&sid=540F94805F1D617F&

 

[Salty John]

You could bodge it but actually the thread form is different, per this advice from a manufacturer of pipe fittings:

NPT/NPS and BSP threads are not compatible due to the differences in their thread forms, and not just the fact that most diametrical sizes have a different pitch. NPT/NPS threads have a 60° included angle and have flattened peaks and valleys (this is a Sellers thread form); BSP threads have a 55° included angle and have rounded peaks and valleys (this is a Whitworth thread form).

At the antenna end of the adapter you need an SO239 socket.

 

[nigelmercier]

... At the antenna end of the adapter you need an SO239 socket.

Thanks for the info, but surely the antenna has an SO239, so the adaptor needs a PL259?

PS I've now looked at the cost of materials to DIY, it isn't worth it.

 

[Salty John]

You're right, of course. Long day. Actually the fitting in the adapter is a fixed-ring recessed PL259 that accepts the PL363 connector which is fitted into the recessed PL259 on the antenna. Whew, clear as mud now, I trust.