ARCHIVE: Australian Ham Radio Discussion Forum ( AHRDF )

Good afternoon,

I have a 80m chirnside helical whip mounted on a large spring mounted on the bull bar. Since the whip has a 5/16" fine thread male base and the spring has a 1/2"female coarse thread, I have to use a brass adapter to mount it on the spring.


To screw the 5/16” whip into the spring’s half inch female thread I use the brass adapter in the attached photo. However the adapter thread is now worn so the whip is wobbly. So  I need to either source a replacement adapter or ditch and replace my set of Chirnside HF whips...!

I expected finding a replacement adapter to be easy, but not so. The gender of my HF helical whips is the opposite of today’s uhf whips - so most of the adaptors on sale are reverse gendered.

Can anyone please suggest a source of a replacement adapter ?

Many thanks

Ian Hill

Two Aussie sites I found on Google

https://www.wagneronline.com.au/threaded.../11439/pd/

http://www.andrewscom.com.au/site-conten...ileone.htm (search for RAS)

(23-05-2018, 04:59 PM)VK3ALB Wrote: [ -> ]Two Aussie sites I found on Google

https://www.wagneronline.com.au/threaded.../11439/pd/

http://www.andrewscom.com.au/site-conten...ileone.htm (search for RAS)

Appreciate you taking the time to respond, Lou.

I saw the Andrews advert, and also one at Mobile One, but their description is reverse gender to what I need (see their diagram attached). Similarly, the Wagner advert is for the reverse gender to what I'm seeking (their's has a female 1/2" and a male 5/16").

The adapter I need will have a male 1/2" end and a female 5/16" end. 

Ian

If all else fails, an engineering workshop could turn one out for you. Won't be as inexpensive, but when there's not an alternative .......

Cheers,

Peter

(24-05-2018, 10:20 AM)VK2EHQ Wrote: [ -> ]If all else fails, an engineering workshop could turn one out for you. Won't be as inexpensive, but when there's not an alternative .......

Cheers,

Peter

Discovered my son-n-law has access to a lathe and all the right gear. Looks like a solution is at hand! ;-) Thanks Peter!

(24-05-2018, 11:06 AM)VK6KIH Wrote: [ -> ]

(24-05-2018, 10:20 AM)VK2EHQ Wrote: [ -> ]If all else fails, an engineering workshop could turn one out for you. Won't be as inexpensive, but when there's not an alternative .......

Cheers,

Peter

Discovered my son-n-law has access to a lathe and all the right gear. Looks like a solution is at hand! ;-) Thanks Peter!

Hope you get more than one made as that arrangement seems like a sure-fire way to shear the 5/16" segment as the HF whip sways around.  Maybe a really good tough steel is called for too....

Hi Peter

Are you sure it is 5/16" Brass tread? As far as I am aware this thread is unique to Australian antennas.

To me in the picture it looks more like a 9/16" UNF thread as more commonly found on overseas antennas? eg such as antennas aimed at the CB market.

If this is the case finding an adaptor should not be a problem.

Igor
VK6ZFG