Retro 1950's CW Rig from N6QW
Join in on the fun and build this rig. But after being given a license by the ARRL, you might also have to learn CW to use this rig ...
What makes this rig different from the plain vanilla 6AG7/6L6 combo is the Plug-In Band Pass Coupler between the 6AG7 and the 6L6. You don't see those every day. My coupler was based on something I spotted in a 1953 RCA Ham Tips on the N4TRB website.
Once set you get a constant output across the CW portion of a band and eliminates the need for a Grid Tuning control to the 6L6. The circuitry consists of two trimmer caps and two powdered iron core ferrites that are link coupled with two turns on each core. The whole assembly is on a PC Board fitted to a salvaged four pin tube base.
Want to change bands simply plug in an assembly for that band. Electrically one half of the network is in the Plate Circuit of the 6AG7, and the other half is in the Grid Circuit of the 6L6. A TKT from N6QW.
The 20-Watt output from this rig coupled with my DX favoring Delta Loop makes for a potent combination.
A note about the Pi Network Tank coil. Something used in the Hybrid SSB was an Iron Powdered core, a T-68-2 wound with 26 Turns of #29 enameled wire was replicated here. Translating an inductance using this core to an actual coil is far easier for me than trying to calculate an air wound coil and the T-68-2 is good to 50 watts.
In work is a companion receiver using COTS assemblies from mostlydiyrf.com. The digital LO opens up possibilities of shifting away from using crystals in the transmitter... now you have a CW Transceiver. BTW in the prototype of this COTS receiver, I routinely hear JA stations on the lower end of 40M CW coming through at 579.
Them that know can make things go.
73's
Pete N6QW