[Milsurplus] Switching Power Supplies for HF Radios

[Ulrich N Fierz]

Hi Ralph
unfortunately most switching power supplies are not designed to run a HF receiver - this also holds true for these nice new wall warts that put out e.g. 12VDC @ 5A, laptop supplies etc. - not just for the odd used supply. 


I needed a portable AC supply for my TenTec 516 Argonaut transceiver providing 13.5VDC @ 7A and I bought a new compact switched supply. Then I installed this in a Hammond cast aluminum box complete with a commercial AC filter (and fuse) on the input and a homebrew toroid (2) - capacitor (some feedthrough) filter on the output. GND is internally only connected to the case at a single point. This has worked beautifully, I cannot hear noise even with a temporary antenna.


In your case starting with $19.95 this might be inefficient - for similar 24VDC purposes (e.g. R-392/URR) I've been able to buy surplus industrial linear supplies that solve the problems.

Wish you luck with your BC-348 - keep the dynamotor!

Regards,
Ulrich  hb9aik - vk6bqd
 
Ulrich N Fierz
Telecommunication Engineering Services
Zurichbergstrasse 203
CH-8044 Zurich
Switzerland
<hb9aik at yahoo.com>