Steve Thompson wrote:
Search around for the W2GN design using a pair in parallel, it works a
treat. I modified the grid circuit to have separate bias control, so it
will work with unmatched tubes. Personally, I don't like link coupling -
it's possible to get false indications of optimum loading.
Ooops - what I meant was - tuned link coupling. A variable untuned link
should give you monotonic loading adjustment, the same as a variable
series capacitor.
Should, but probably won't. Most link-coupled VHF/UHF amps suffer from
chronic under-loading, because it's very difficult to make the link
coupling tight enough to load the tube(s) correctly.
In contrast, capacitively-coupled VHF/UHF amps tune and load as easily
as a pi-network.
The W2GN articles appear to be downloadable from:
http://www.newsvhf.com/w2gn.html
(I wasn't able to verify that - please can someone confirm?)
--
73 from Ian G3SEK 'In Practice' columnist for RadCom (RSGB)
http://www.ifwtech.co.uk/g3sek
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