Hi Europa members,
I realise this thread is a year old but I just came across the same problem in
trying to find the Philips Toroids P/N 4330 030 34420 that were recommended in
the VHF Antenna build manual. You will need four of these for the VHF antenna
construction.
I'm fortunate because I work for a major Avionics company here in Sydney
Australia
and I had the Chief Engineer look at the specs for these toroids and he advised
that you cant just use any old toroid - as suggested by someone in this
thread. They all are manufactured for different frequencies and applications.
One other piece of advice he offered is that if you are using copper tape to
make
the antenna, use the widest tape that you can find as this provides better
performance over the entire VHF spectrum 118 - 136Mhz. In other words if you
used thin tape, you will only have best performance at the mid-frequency but not
so great at either end of the spectrum.
The first number in the Philips toroid P/N "4" refers to the "mix" in the
ferrite.
It is suitable for VHF at 100MHz. He found a suitable replacement that had
an inside diameter is 5.4mm that will slip over RG400 (4.9mm) safely.
You can buy then in a pack of 10 from RS Components. In Sydney I can buy them
for
about $15 (including delivery).
check http://au.rs-online.com/web/p/ferrite-rings/1741229/
I hope this helps.
Regards,
Tony Vaccarella
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Tony Vaccarella
Mascot NSW 2020
Sydney Australia
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=431670#431670
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