My older K3 (3481) began operations with a PR-6 which I found to be an excellent 6 meter preamp. I too was dissatisfied with the K3's sensitivity on 10 and 12 meters so I experimented with some CATV preamps I bought at flea markets for $1. These provided good gain all the way down to 10 Mhz!
When the PR6-10 came out I bought one. I felt that the PR6 -10 is/was a great preamp and better than the preamp in the original K3. When combined with the internal preamp, the results are outstanding down through 14 Mhz. There is an internal high pass filter the PR6-10 which cuts off gain below 14 Mhz. The PR6-10 has a major weakness. The RF transistor is very sensitive to static and RF voltage. I have destroyed two of the microchips, one I believe due to static buildup and one due to a spike from my 6 meter amp, a converted SB-200. I still have my PR6-10 but most of the time, I am using my cheap $1 preamp on 20 through 6M. The current one is a Gemini DA1100 cable VCR VHF/FM 10 db amp covering 50-450 Mhz. Again, they work all the way down past 10 Mhz. This little units have a built in power supply and are usually a little chrome box. They might also carry the name RCA or Radio Shack but are essentially the same. I use short patch cables to switch them in and out. Even though they are 75 ohm in/out, it doesn't seem to affect operation. For the above reasons, I won't do the preamp upgrade board for my K3. 73 Dennis W0JX ______________________________________________________________ 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 Message delivered to [email protected]
