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

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

Thanks Steve great help ....here goes!!!!!!!!!!!!!!!!!!!!!

Barrie

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

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

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

the randon wire / 9-1 unun arrangement actually DEPENDS on a tuner.

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

Thanks Steve,Bonehead..............longlive the dipole