Hi Jim, after I finished with a set for 70cm and 2m I measured the I.L. and SWR
through the entire system at both frequencies. The system being a transformer
at each end, a pair of N-connectors and 300' of 7/8" CATV line. I remember by
using a Bird dummy load and Bird watt meter the I.L. was 3-4 tenths of a dB
better than what the manufacturer of the cable had specified for 2m. I don't
remember how much better it was at 70 cm off the top of my head but there too
it was better than the cable spec. At that point I felt pretty happy and that
the loss in the connectors and transformers was negligible and finished the
science project. I'm sorry to say but I did not go any further to try to
determine the loss through a very short length of cable and a pair of
transformers.
73,
Gedas
----- Original Message -----
From: Jim Lux
To: Gedas ; TowerTalk@contesting.com
Sent: Saturday, February 24, 2007 5:27 PM
Subject: Re: [TowerTalk] re Hardline connectors
At 12:34 PM 2/24/2007, Gedas wrote:
>I don't know if it will help you but sometimes seeing a picture or
>two can really help out in these situations. I ended up making all
>kinds of terminations for some 7/8" CATV line for VHF and UHF
>several years ago. At first I was pretty reluctant to try to make
>up the transformers. It was designed purely from scratch and
>formula and they worked just fine. Once I made a set and played
>around with them I saw it was really no big deal. Each set I made
>after that point kept getting better and better. Years later they
>are still in use with perfect SWR.
Have you made any loss measurements on the transformers? Just sort
of curious what loss people get from real devices as opposed to what
you calculate by turning the crank on the equations.
Jim,W6RMK
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