Category Archives: EME and Meteor Scatter

LARCAN EME SSPA

I have recently acquired an M2 1K2 SSPA so the LARCAN is now for sale. I was guilty of overdriving the Larcan so one FET needs to be replaced. Will sell for $450 plus shipping as-is or $900 after repair with a new MRF151G FET. —- I will throw in the HP power supply for free.

My EME Amplifier is a modified LARCAN. These are surplus TV transmitting amplifiers which can easily be modified for use in the 144MHz ham band.

The LARCAN Requires 50V at 40A to make a KW output. The typical solution is to use an HP Server power supply which can be picked up on EBAY for $30.

The HP server power supplies work well, but have high fan noise, and are pretty bad EMI generators. You must take extra measures to reduce the EMI emissions. On EME, even one or two dB of extra noise is not acceptable. The best solution would be to mount everything in a metal cabinet. I have a nice wood shop, so I built a wooden roll-around box and lined it with radiant barrier material. This worked great, but xyl complained that it is ugly.

I was browsing EBAY and ran across a seller who has a bunch of Kepco/TDK RKW 15-22K power supplies. I bought six of them for $37 each.

The RKW 15-22K is adjustable from 10 to 18V and delivers 22A. These power supplies are designed to be run in parallel with provisions for master/slave and current balance. So with a pair you have 44A. If you put three pairs of these in series you have 53V at 44A. Viola!!!

These Kepco RKW power supplies are extremely well made and meet the very strict EU emissions requirements. No noise emissions from the new power supplies for the Larcan.