[TowerTalk] Balun for Force 12 6 Element 20 Meter

[jimlux]

On 7/21/20 1:26 PM, Steve Maki wrote:
> On 07/21/20 15:49 PM, jimlux wrote:
> 
>>> I've seen similar issues and no longer depend on the normal bolt and 
>>> nut shield connection when there is a layer of PVC involved which is 
>>> compressed by the bolt & nut. Any shrinking of the PVC will cause an 
>>> intermittent connection. Most commercial baluns are still made this way.
> 
>> Or 4 nuts - nut1 wire nut2 pvc nut3 wire nut4
>> The preload between nut1 and nut2  and the preload between nut3 and 
>> nut4 are what make the contact. Takes two wrenches to get it tight 
>> enough.
> 
> I thought of that, but then you have a nut between the SO239 flange and 
> the box. It starts getting messy. BTW just so we're on the same page - 
> the connector flange is on the outside of the box, which is almost where 
> it has to be for ease of assembly.

I was thinking of the *wire* connections (e.g. to the driven element) 
where you'd have two studs that you'd hook a wire with a lug to.




> 
>>> Instead I replace one of the 4 machine screws with a solid #14 or #12 
>>> wire that is soldered to the SO239 and sticks into the box 3/4" or 
>>> 1", which the coax shield can then be soldered to.
> 
>> That works fine for a coax connector, although now you've got a 
>> "non-disconnectable" connection.
> 
> The center conductor is soldered to the center pin, and the braid is 
> soldered to the *ground pin*. What's not dis-connectable?
> 
>> Actually, a banana jack/plug would probably work. They're spring 
>> loaded, so they don't have thermal cycling issues.
> 
> I realize now the OP was talking about the antenna/binding post side of 
> the box. I haven't had a problem on that side, probably because there is 
> a large flat washer on either side of the PVC.

Yes..



> 
> -Steve K8LX
> 
> _______________________________________________
> 
> 
> 
> _______________________________________________
> TowerTalk mailing list
> TowerTalk at contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk