[Elecraft] Chirp with K2/XV222

[Steve Kavanagh]

I got a report of chirp when running CW on 222 MHz during the VHF contest this past weekend. 
This has been confirmed by a few others since the contest.  It's quite possible that the various voltage
drops from the Rover vehicle battery to the XV222 were not leaving enough headroom for the 78L09
local oscillator regulator.  I am not sure this is the problem, but it certainly is plausible. I am looking
at various approaches to fixing this, but I wonder if there is anything that can be done to make the
XV222 a bit less sensitive to low voltage.  For example:

(1) change the reverse polarity protection diode to something with a lower voltage drop.  The manual
says it's an SG530, for which I cannot find a data sheet....is it the same as an SB530 by any chance ?
(2) change the regulator to an 8, 8.2 or 8.5 volt unit.  All of these exist in TO-92 format though some
are getting hard to obtain now.  Would the oscillator start reliably ? Would there be enough LO
power for the mixer ?
(3) change the regulator to a low-dropout type.  I can't find any 9 volt TO-92 LDO regulators so far.
Does anybody know of a source ?  I suppose a tiny SMD board could be piggybacked....

Has anyone any specific info on these ideas or other possible mods ?

73,
Steve VE3SMA