70cm Dvb T Amplifier

It seems that on 70cm it is easy to find a surplus amp. I found one with 2xBLF 861A which can deliver 250W out on 432MHz. I had a nice heat sink already.


One thing needed is the PSU. 28-32V and quite a few Amps. Since I have a larger QRO amp as well I decided to make a 60A PSU. This one will probably be happy with "only" 17A.

I use 4 15V 15A power supplies. 2 in series and then parallell coupled



Initial test:

10dbm out from the 8656B was 11.7dbm on my SA including 2pcs 30cm RG-402.


With 10dbm drive the output is 26.6 on the SA. -11.7 yelds about 15db gain. Not bad. If the amp is reasonable linear, full 250W out needs 8W of drive.

I will soon have a better power meter with calibrated directional coupler.









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