>Rich said;
>
>>EUR no RF input is needed when it makes its own.
>
>I would be inclined to do the first sets of tests with a 50 ohm load on the
>output, and the transceiver connected to the input (transceiver in
>transmit, but
>delivering NO power). That way, the amp is seeing something like reality
>as far as source and load impedances are concerned. When it's stable that
way,
>you can try the 'no input - no output load' - it ought to be stable like
that.
? the sticky wicket is that the c. 100MHz energy never sees the 50? load
because the tank is a low-pass filter config.
>572Bs aren't the easiest of bottles to tame as far as parasitics go - the
internal
>structure has a lot of inductance,
? amen
>and if new ones have a bit higher gain, it
>could easily tip the balance. I suspect that the amount of suppression
>inductance needed ends up being such that of necessity, a fair amount of
>power will get dumped in the suppression resistors. This means that 10metre
>efficiency will be down, although the suppressors will help keep the room
warm.......
>
? However, the loss of a couple of percent of P on 29MHz is probably not
going to be noticed on the Rx end.
>I believe that 572Bs were originally intended as Class B zero bias (or nearly
>so) AF power tubes for AM modulators.
>
? So it seems.
cheers, Peter
- R. L. Measures, a.k.a. Rich..., 805.386.3734,AG6K,
www.vcnet.com/measures.
end
|