It is currently Mon Nov 18, 2019 2:29 pm

Click the link below to visit the site sponsor

The Ham Radio Shop




Post new topic Reply to topic  [ 9 posts ] 
 9-1 Unun Saga!!!!!! 
Intermediate Member

Joined: Tue Apr 17, 2012 1:40 pm
Posts: 63
Location: Northants
Feedback: 3 (100%)
Reply with quote
Post 9-1 Unun Saga!!!!!!
Hi Steve

Further on to my previous topics re .longwire etc.I have tried various lentghts from books and other fellows but i cant seem the get the end fed / wire working.
Ian at Gwhip advised 22m radiator and 20mtr counterpoise which i also tried
The measurements on the analyser is showing a constant 50ohms with complete end stop (red) SWR
I contacted Geoff at Gwhip who has been very helpful but as it was a SH sale on HRD he can only offer limited support which is fair enough however it is possible that the unun has been subject to high power and damaged the unit,my question Steve could you advise on how to meter out the unun to check the wiring is intact???

Thanks Steve

Barrie


Mon Aug 06, 2012 12:31 pm
Profile Send private message

 9-1 Unun Saga!!!!!! 
Moderator

Joined: Fri May 22, 2009 1:23 pm
Posts: 5662
Location: Northampton IO92ME
Feedback: 1 (100%)
Reply with quote
Post Re: 9-1 Unun Saga!!!!!!
Barrie,

If you put a couple of 220 Ohm resistors in series and connect them across the UnUn secondary - that's between the antenna connection and ground - you should measure something close to 50 Ohms across a wide range of frequencies with the analyser connected across the UnUn input.

A DC check wont tell you much, but every UnUn terminal should measure zero Ohms to all other terminals.

73,
Steve G3TXQ


Mon Aug 06, 2012 1:38 pm
Profile Send private message WWW

 9-1 Unun Saga!!!!!! 
Intermediate Member

Joined: Tue Apr 17, 2012 1:40 pm
Posts: 63
Location: Northants
Feedback: 3 (100%)
Reply with quote
Post Re: 9-1 Unun Saga!!!!!!
Thanks Steve great help ....here goes!!!!!!!!!!!!!!!!!!!!!

Barrie


Mon Aug 06, 2012 2:51 pm
Profile Send private message

 9-1 Unun Saga!!!!!! 
Intermediate Member

Joined: Tue Apr 17, 2012 1:40 pm
Posts: 63
Location: Northants
Feedback: 3 (100%)
Reply with quote
Post Re: 9-1 Unun Saga!!!!!!
Morning Steve

Did the test with the resistors,worst worst SWR was 1.2.1 with 47 to 52 ohms throughout so I guess the unun is fine ??..can't understand what i'm doing wrong... ??????????

Any Ideas?
Thanks
Barrie


Wed Aug 08, 2012 9:18 am
Profile Send private message

 9-1 Unun Saga!!!!!! 
Moderator

Joined: Fri May 22, 2009 1:23 pm
Posts: 5662
Location: Northampton IO92ME
Feedback: 1 (100%)
Reply with quote
Post Re: 9-1 Unun Saga!!!!!!
Barrie,

Looks like the UnUn is fine!

When you said in your original post " i cant seem the get the end fed / wire working", what exactly did you mean? Do you realise that you shouldn't expect to see a low SWR with that antenna?

73,
Steve G3TXQ


Wed Aug 08, 2012 9:34 am
Profile Send private message WWW

 9-1 Unun Saga!!!!!! 
Intermediate Member

Joined: Tue Apr 17, 2012 1:40 pm
Posts: 63
Location: Northants
Feedback: 3 (100%)
Reply with quote
Post Re: 9-1 Unun Saga!!!!!!
Thanks Steve

gonna do some more tests and see what the actual SWR readings are on a meter not the analyser??.I suppose the thing is I dont like using tuners because ive nevr had to all the antennas I have up or built are not above 1.5.1 most i resonate about 1.2.1.

keep ya posted ,thanks for your help

B


Thu Aug 09, 2012 6:50 pm
Profile Send private message

 9-1 Unun Saga!!!!!! 
Contributor 2019
User avatar

Joined: Mon Jul 28, 2008 12:00 pm
Posts: 2698
Location: Warrington-ish......... IO83ql
Feedback: 103 (100%)
Reply with quote
Post Re: 9-1 Unun Saga!!!!!!
the randon wire / 9-1 unun arrangement actually DEPENDS on a tuner.

_________________
Heil - Icom - Expert - Mosley

from here, to the world.


Thu Aug 09, 2012 7:40 pm
Profile Send private message

 9-1 Unun Saga!!!!!! 
Moderator

Joined: Fri May 22, 2009 1:23 pm
Posts: 5662
Location: Northampton IO92ME
Feedback: 1 (100%)
Reply with quote
Post Re: 9-1 Unun Saga!!!!!!
All the UnUn does it reduce some of the very extreme SWRs that you would otherwise get on some bands, to something more moderate; that limits the losses in the coax feedline to acceptable levels.

Take a look at the second chart on this page from my web site:
http://www.karinya.net/g3txq/unun/
Taking 80m as an example you'll see that the UnUns have reduced the SWR from over 100:1 to about 25:1.

The UnUn can't produce a perfect match; that system is meant to be used with a tuner, like bonehead said.

73,
Steve G3TXQ


Thu Aug 09, 2012 9:10 pm
Profile Send private message WWW

 9-1 Unun Saga!!!!!! 
Intermediate Member

Joined: Tue Apr 17, 2012 1:40 pm
Posts: 63
Location: Northants
Feedback: 3 (100%)
Reply with quote
Post Re: 9-1 Unun Saga!!!!!!
Thanks Steve,Bonehead..............longlive the dipole :) :)


Fri Aug 10, 2012 11:00 am
Profile Send private message
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 9 posts ] 


Who is online

Users browsing this forum: No registered users and 0 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Jump to:  
cron
Powered by phpBB © phpBB Group.
Designed by Vjacheslav Trushkin for Free Forums/DivisionCore.