Re: uBitX reduced power option

Jack Brabham - KZ5A
 

RV1 is useful to reduce power which is already low above 40M.   Good feature if you would prefer a 1 watt rig.  Increasing power boils down to running higher Vcc on the PA and upgrading the PA cooling. 

I am building a V5 with front panel variable PA voltage, I expect to have to interconnect the variable Vcc with the PA bias circuit so that it tracks as required.

Getting rid of the power fall off above 40 involves replacing most of the transistors in the TX chain, all of which have reduced gain at higher frequencies (20M and above).   I really wish Farhan would raise the price a few bucks and put decent transistors in it in the first place.

73 Jack KZ5A



On 7/13/2019 3:59 PM, N8DAH wrote:

Mark RV1 will adjust the drive power this can be remote mounted with use of a good shielded cable. RV2 and RV3 are bias control of the two IRF510's.

When I had a V4 I had adjusted it to 5w on the lowest bad (80m) so I could drive an amp as well as save the finals while doing full duty cycle modes.

73
--
David

 N8DAH
Kit-Projects.com

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