Jump to content

Recommended Posts

Dear All,

Hoping this isn't a silly question ?

I want to use the Clansman mount, (Photo's A & B) with a 2 metre  amateur radio set in my LR wolf.

In the top part of the mount (Photo  C & E)  there is a transformer / balun.

If I by pass the transformer / balun  (Photo F) and use a quarter or five eighth  wave length of Clansman aerial rod. will that suffice  or am I missing something ?

 

Thanks,

Barrie

2W1GMM

A.jpg

B.jpg

C.jpg

D.jpg

E.jpg

F.jpg

Edited by Barrie
Link to post
Share on other sites

Thanks for the reply

And that was going to be my next route, however my friend has offered to respray the Wolf so everything on hold at the moment until Wolf prepped, sprayed and ancillaries  bolted back on.

will keep you updated

 

Link to post
Share on other sites

It isn't a balun as you are going from unbalanced co-ax to an unbalanced whip. I believe from memory that it is an auto transformer designed so that there is a DC path from the whip to ground/vehicle chassis in case of contacting overhead power lines. It may or may not work effectively on 2m. Being designed for the mil band the ferrite may not be suitable. I think I would remove it and just feed the co-ax straight to your quarter wave whip cut for 2m. 

Or you could do some tests with and without it to some distant friend and try and see if the received signal strength changes with and without it.

 

Link to post
Share on other sites

Gordonb,

Thanks for the info.

Unfortunately it  will have to wait a while as a friend has just offered to re-spray the Wolf in a couple of weeks time, so I’ll be slowly stripping everything off the vehicle.

When It’s all back up and running and radios, antennas etc installed will try an experiment or two and post the results. Won’t be for a while though.
 

 

 

Link to post
Share on other sites

As said, it isn't a balun.  Just remove it from circuit as you've suggested and then use a VSWR meter to cut a whip to a suitable length.  I've done this before and it works.

Andy (M0IJH)

Link to post
Share on other sites
  • 2 months later...

Barrie

I have also bypassed the transformers (UnUns?) to allow direct feed of a quarterwave whip on 4m and 6m. They do appear to have an impedance matching role because the 1/4 wave looked nothing like it should to an antenna analyser until the transformer whatever it is was bypassed. One slight caution - the pigtail from the antenna clamp to the tag in the matching unit is getting to be a significant part of a 1/4 wave at 2 meters and is somewhat coiled when assembled, so the correct resonant length of rod is a bit less than expected - this is noticeable on 4m and expect will be quite significant on 2m. 

Iain

73 de G0OZS

Link to post
Share on other sites
9 minutes ago, g0ozs said:

Barrie

I have also bypassed the transformers (UnUns?) to allow direct feed of a quarterwave whip on 4m and 6m. They do appear to have an impedance matching role because the 1/4 wave looked nothing like it should to an antenna analyser until the transformer whatever it is was bypassed. One slight caution - the pigtail from the antenna clamp to the tag in the matching unit is getting to be a significant part of a 1/4 wave at 2 meters and is somewhat coiled when assembled, so the correct resonant length of rod is a bit less than expected - this is noticeable on 4m and expect will be quite significant on 2m. 

Iain

73 de G0OZS

Yes, noticeably shorter than you might expect - around eighteen inches from memory.

Andy

Link to post
Share on other sites

Iain / Andy

Thank you for the info.

My LR Wolf is currently with 'the man with a spray gun', should be back in the next day or so and then the start of the build up.

I would have expected a 2 metre quarter wave rod to have been around 19 (+) inches. However being shorter is going in the right direction, easier to take off metal than to add it !

.... and the next problem relates to a non working RT320, but I'll start a new post on that.

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...