If a 2-meter version of the KPA500 ever gets to the drawing-board stage, I'd vote for two-band capability, adding 6 meters; this would be ideal for VHF/UHF contesting, as it would provide a single amp for the two most-used bands in those contests. I think that trying to stretch it to 432 mhz would be a much more difficult design challenge, since it would require more modification to the circuitry than substituting a different power transistor, whereas you might be able to accommodate 2 meters with the existing board layout or something similar.
Lew K6LMP On Sep 6, 2011, at 7:48 AM, Allan G Duncan wrote: > 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 > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[email protected] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
