2014-06-02
A cheap pre-amplifier for receiving amateur satellites 5 years ago
I was looking for options for a pre-amplifier to amplify the incoming antenna signal for receiving amateur satellites in the 70cm band (430-440 MHz). Commercially available units seem to be quite expensive like this one: DBA 270 Duo-Band-Preamp. 2m + 70cm - SSB for 298 euro. A cheap option seemed to be Low Cost 440 MHz Receiver Preamplifier Kit - Ramsey Electronic Kits for US dollar 9.95. Oh, and US dollar 57 for shipping it to the Netherlands. I'll skip. Other options sofar seem to be quite expensive or require SMD soldering. I decided I have enough problem seeing normal soldering with a magnifying glass so I'll skip SMD soldering for now. A cheap but not ideal trick is (ab)using a cable TV amplifier: those include the 70cm band because they include everything from around 88 MHz to 1000 MHz. I found this suggested at KickSat Ground Station. So I walked into the local electronics store and found a cheap cable TV amplifier with a special sticker "does not support digital interactive TV" which means it doesn't support the returnchannel. Good, just a simple amplifier. The specific impendance in cable TV networks is 75 Ohm and I want 50 Ohm so that will probably have to be fixed too. It came with a small power supply which will be replaced with a battery like in the kicksat page.