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Dug out the manual and schematic diagram. The long pins on the DC connector supply power to the bias / VSWR board. Removing 50VDC from that pin would remove the 39V bias to the transistors should effectively shut things down. Anyone able to confirm this in operation?

Has anyone made progress with the 1kW modules? I'm contemplating building a dual band amp, two modules in slide in Larcan drawers, power supplies, etc all mounted in a single equipment rack. I've dug up coaxial switches, cables, etc and basically need to reconfigure the rack and glue it all...

I like the airport in Barra, Scotland. The planes land on the beach during low tide. http://en.wikipedia.org/wiki/Barra_Airport_(Scotland) http://www.youtube.com/watch?v=STqmbc8k9rU

Try building a coaxial balun. Two styles come to mind. 4:1 using a half wave line between the two outputs. 1:1 using a quarter wave sleeve. I've seen this type integrated into FM broadcast antennas rated at about 15kW. There should be information in the ARRL radio handbook or their...

It looks like part of Miniature Wonderland in Hamburg, Germany. Miniatur Wunderland Hamburg - model building - model railway Hamburg

I have several Larcan 1kW lo/lo amplifier modules for use on either 6-meters or modify for 2-meters. Lots of info online. I also have 1kW high band VHF modules. These will work well at the 220MHz band. I'm not confidant of their operation at 2-meters and have not seen credible...

Buy or build a switch anyhow. If nothing else you can connect a dummy load to the other port and measure SWR of the switch.

You may be able to mount three connectors on a small metal box along with a simple toggle switch. Nothing fancy is needed. Keep the wire leads short and the SWR should be entirely acceptable.

How does the coaxial cable attach to the antenna?

Home generator installation

The Larcan transmitters did not have significant voltage regulation on the 48VDC bus. Essentially they used very large capacitor banks after the rectifiers. If you dropped the input voltage to half the PA voltage would drop as well.

The upper half could be Larcan 6M, 2M, and 1.2M with 48V power supply. Band switch by changing out modules. The lower half is UHF with a separate 28V power supply.

Why just one? Go QRO on 6M, 2M, 1.2M, and 70cm!

Let me make a few calls and see if there are better specs available. Maybe I can borrow one to run a few tests and take pictures. All I know is each module is rated 1kW and requires 28VDC @ 80A. They use oddball output connectors too...

Someone offered me a couple of 1kW UHF television amplifiers. I suspect they will work from 470MHz to at least 800MHz, and likely cover the 430-450MHz band as well. Is there any interest in high power UHF, or better to pass on these?

Open the cabinet and look at some of the transistors and ICs. Often after the part number is a manufacturer date code. Find out when the ICs were made and it's a good chance the radio was built shortly afterwards.

CB stuff works on an entirely different set of rules, half of them are magic. The sync compression is due to non linearity in the amplifier. I think there were amplifier problems, possibly FETs only partially working. Simply being able to bias to 500mA does not guarantee the FETs are good...

I didn't look at the MRF151 spec sheets. I edited an email for amplifier troubleshooting. The first page describes some problems with a 3kW transmitter, but the following sheet seems to be for 6kW. Might be some information in there that could help...

There was an extra stage of amplification prior to the high band amplifiers, so they do require more drive for full power output. Looking at my notes the high band units require about 4x the drive power. I don't know the maximum drive level the transistors will withstand. Simply pushing them...

Let me know, still lots available. Found a possible lead on another stash, possibly another 14 or 28 lo-lo modules.