Just when SPE decided to upgrade their 1k3 amp. to use a 1k5 transistor:
http://www.richardsonrfpd.com/Pages/Product-Details.aspx?productId=1241241
So, 65 Volt looks to be the new 50 Volt, but surely the problem of getting
the heat away from the junction is getting worse. Personally, I wish the
amplifier manufacturers' would adopt a more modular approach - run the FET
around the 800 Watt level, where there's a fighting chance of easy matching,
keeping them cool and getting reasonable linearity, and conceive a system to
allow users' the ability to buy and combine as many power modules as they
require. I believe Flex has gone some way toward this approach, in that they
are using two devices in their new SS amp., to ease some of the design
challenges.
Good to see that Elecraft is looking to release a 1k5 model. I could not
find any info. about the new Elecraft in the FCC database, but the link
below is a good one for the curious:
https://fccid.io/frequency-explorer.php?lower=1.8&upper=54&exact
I think we are truly seeing the sun setting on valve HF PA and analogue
front-end transceivers. The combination of big LDMOS FET and majority DSP
TRx, with whole-chain linearity correction, is delivering some of the
cleanest SSB signals ever heard on the amateur bands. It's still fun to play
with those examples from the last 50 years of our history though!
Regards,
Mark.
*******************************************************
Mark Hill - G4FPH
E-mail: g4fph@mjha.co.uk
Website: www.g4fph.net
WebSDR: www.160m.net
*******************************************************
Dipoles resonant on 1935 / 3720 / 5345 / 7125kHz
*******************************************************
Remember - SIDE for HV safety:
S witch off
I solate
D ump
E arth
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