A
BP filter for my next QRP Transceiver
I
came across this YU1LM interesting side a time ago. Really interesting result. I build
tree of this filter to check the performance, and get very close to the
description but I don’t use so accurate values, that’s way I think it is worse
loss in the passband. But I will go for this type.
I has also tested pin diodes
and other diode to use as switch, BAT18, BAP70-3, BAP51-02, BA592, BAP50-04 and
1N4148, I chose BAP70-03. I have read that some has problem with IM product
when using diodes my test don’t show up worse with diode compared to without.
I
use 2 generators and a hybrid combiner a generator G1 in passband -12 dBm and
G2 to different frequencies to test for IM -70 - +17dBm. If there is IM product
it is worse without filter, so I can’t blame the diodes for that.
dokument
http://yu1lm.qrpradio.com/INPUT%20HF-6m%20BP-LP%20FILTERS%20FOR%20SDR%20TRANSCEIVERS%20-%20YU1LM.pdf
The Measurment.
Stay tuned
I working on PA for QRP.
de SM4HNG
