So far I haven't found anything wrong as such on #3764:
The LPF components appear fine (value and condition), and check out ok with
an MFJ analyser for SWR on receive.
T1 and T2 and associated components appear ok. One thing; C83 is 1000pF,
not 1200pF as per circuit. However I tried padding that with a 220pF SM and
it made no difference. Looks like 1000pF was supplied with the kit.
I've realigned the BPF on 160/80m, which was pretty much ok anyway.
I've re-adjusted the bias, which was also ok.
I've readjusted the pwr sense pot, again was ok.
With the PA disabled the base K2 draws about 2.5A @ 10W op on all bands.
With the PSU set to exactly 13.8V, and measuring the current (V across
10x0R1 6W in parallel, in series with V+) I get the following, into a 50R
load. Current on the PSU display reads similar.
Set power W Current A 160m Current A 80m
50 14 14
60 15 15
70 16.5 16.5
80 18 18
90 24 19
100 27 20
110 29 21
The actual power out is similar to the set power, to about 10%. So
topband behaves ok up to about 80W op. This also happens from a cold start,
so I don't think it's thermal runaway.
No instabilities are apparent on a scope or spec. an.
Any suggestions appreciated. Thanks / 73 Fraser G4BJM
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