Monday, March 13, 2017

A Solid State QRP Rig from 1955!

A 1955 Solid State QRP Transmitter using the Philco SB-100.

3/14/2017 ~ Late breaking -- I put a 4:1 transformer in the collector lead and as measured across 50 Ohms on the secondary side I am seeing 3.2 Volts Peak to Peak. If you perform the rigorous calculation that transforms into 25.6 Milli-watts or 14 dBm. Now we are cooking! That is better than the rig on Bill's blog.

See Photo addition at the end --just to posit where 60+ years have taken us --and I have personally seen the amazing change to our tools, techniques and toys!

Recently my friend Bill, N2CQR posted data on his blog ~ about a vintage late 1950's early 1960's 10 milliwatt 10 Meter transmitter. That was quite a feat!

But given my Italian heritage I could not let that pass without building my own solid state transmitter using a transistor from 1955. My rig operates on 14.060 and produces 0.4 milliwatts with a 3 volt collector supply using a Germanium transistor from Philco. The SB-100 was one of the first RF transistors that could work all the way past the 10 Meter band. The max Pout was 10 milliwatts --so mine is just loafing along.

This was fun.
Pete N6QW
It must be easy to misunderstand when someone says wire wrapped it is decoded as wire tapped. Hmm wonder who recently did that?