JOHNSON VIKING

The Johnson Viking II was probably the best HF transmitter for AM and CW ever made. It covers nearly all frequencies from 1.8 MC to 30 MC continuously. There was even the coveted CDC model Viking II that had no gaps in coverage, due to its intended use for Civil Defense stations. It is ideal for modern time CW operation on the WARC bands, assuming you have a crystal or feed the VFO input with the proper frequency. You can use the original Viking 122 VFO or a modern synthesized digital VFO for wider frequency coverage. 

It employs WW2 surplus parts and is built like a brick outhouse. It does not use some cheesy pi network inter stage coupling network. It is all parallel tuned. This avoids subharmonic problems. It has been popular for use as a Pirate Radio Transmitter, but it sounds terrible with the stock audio. I believe that this transmitter is better than the Valiant because it has a roller inductor in the final and unlike the Valiant, the transmitter and VFO cabinets are copper plated and well shielded for RFI.

Modes: AM/CW
Bands: 160 – 10 Meters bandswitching
Input Power: 135W-AM, 180W-CW
Power Supply: Internal
Final Tube(s): 2x 6146 parallel
Modulator: 2x 807 (PP)
1952-57
Size: 10.25″h x 20.0″w x 13.0″d
Approx. Weight: 70 lbs

 

 

LINKS:

Johnson Viking II Manual

http://wireless-girl.com/Projects/AMTransmitters/JohnsonViking2.html

 


 

A VFO 80 / 40 m for the Johnson

The VFO is a Wavehunter dual channel VFO based on a single BF245C FET. It gives a moderate amplitude signal and has high output impedance.

 

The Johnson Viking II needs a fairly large input signal at the VFO socket. Here are two extracts from the Johnson Viking II manual.

Therefore the Wavehunter VFO must be followed by a buffer-amplifier. Based on the above Johnson information and taking some margin, its output capability for the 40m band should be:


 Minimum: 6 V rms (17 Vpp)
 Target: 8 to 12 V rms (23 to 34 Vpp)
 Maximum: 15 V rms (42 Vpp)
 Load impedance: 25 kΩ

Thanks to Alain, F1LAG my brother, for his help and the nice buffer.

 

>>>>>>>>>>>>>> Read more about the VFO buffer from F1LAG

 

The frequency meter…

I first tried with a small Chinese tool. Nice but impossible to plug directly. The only way was to do a coupling. And after some hours the display disapeared…

Finaly i used a small frequency meter found in a Hamfest for 2 euros… The knob is coming from a DDS AOR used with my Collins line.