Peter Sundberg wrote:
>I am perfectly comfortable with my QBL 5-3500 G2DAF amp without any
>parasitic suppressor. It runs all bands, stable as a rock. No special
>arrangements except the screen is bypassed with a PTFE "sandwich"
>capacitor, same technique I use in the VHF/UHF amplifiers. Also the wiring
>between input and output is done to preserve as much isolation as possible.
>The tube has full specs (4kW out) up to 110 MHz so it is not like the 813's..
>Supressors not needed in all amps it seems..
This ties in exactly with what Tom was saying. If you build HF
amplifiers with the kind of "VHF awareness" that Peter has, you don't
have many problems with unexpected VHF resonances.
On the other hand, if you build an HF amp using only "LF awareness",
with long leads and unsuitable components that behave strangely at VHF,
you can get some very nasty surprises!
73 from Ian G3SEK Editor, 'The VHF/UHF DX Book'
'In Practice' columnist for RadCom (RSGB)
http://www.ifwtech.com/g3sek
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