[Heathkit] HALLISCRATCHERS BC939

[mrapps at grandrapids-mn.com]

The BC939 was intended to match a 35 foot whip to the BC610 from 2 to 18
mc.  Considering the losses in the 5 turn input link, any antenna could
look matched.

HW-12s had fixed output cap.  Pretty much 50 ohms only.

Have fun

KoDCF / Tony



As Glen has posted, the "era" of SB-102s, HW-101s, and for that matter
The HW-12s and others did very well loading with their Pi-networks.

I only had to go to an external tuner to demonstrate that I could load a
bedspring and talk from my wife's sisters house with a piece of enameled
wire.

The current solid state equipment either requires one due to the
"foldback circuitry" to deal with the SWR that is exhibited when you get
out of the "sweet spot" that a doublet is cut for.

Then again, the BC-610s and other "tall ships" on AM,, sometimes require
one.  I have the BC-939 for the two BC-610s.  However, you also have to
keep in mind that the BC-939s are NOT antenna tuners.  They are antenna
COUPLERS.  There is a big difference!  There is NOTHING that is even
remotely close to a 50 to 75 ohm output impedance from a BC-939.

I can't remember whether I used a homebrew tuner or something that was
purchased to load those bed springs with that single wire.

Bob - N0DGN