[Elecraft] [KPA500] - 144MHz Version?

[Allan G Duncan]

I was recently studying the schematics of the KPA500 and looked at the
specification of the VRF2933 devices which are used in the RF deck of the
amplifier. I noted that the devices are rated to 150MHz which made  me think
a 144Mhz version of the KPA500 would be a nice addition for a K3 equipped
with a K144XV 2m option (or indeed any 144MHz transceiver). Nearly all the
existing KPA500 metalwork, PSU and front panel PCB (with different firmware
and no band buttons) could be carried over with a different RF deck (perhaps
using the same VRF2933 devices and heatsink). A 2m version could potentially
be lower cost as the switchable complex LPF arrangement of the HF/6M KPA500
would not be required. The RF deck aside, the R&D costs would be low, using
much of the already proven KPA500 hardware. The 500W output is ideal for
here in the UK where the power limit is 400W. Even a 432Mhz version could be
created although the VRF2933 devices would have to be replaced with
something else - I suspect the demand for this 70cm version would be far
lower than that for 144MHz and would not be cost effective for Elecraft.

I currently use a Henry Tempo 2002 using two Eimac 8874 on 144MHz. I think
that a 144MHz KPA500 would be cheaper than obtaining two replacement tubes
for my existing amp! I would certainly be very interested in the purchase of
a 144MHz KPA500 (KPAV500 ?) - anyone else?

On a slightly different matter, I note that the KPA500 front panel PCB
schematic also has an unused "2nd RF deck" connection - perhaps for a future
KPA1000 utilising two of the KPA500 modules combined?

73

Allan
GM4ZUK