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On Aug 3, 6:37?pm, "Tio Pedro" wrote:
Has anyone tried a 6JH8 in place of a 7360 for the
first mixer in a homebrew RX? ?How did they compare?

Pete

Back in the 1960's, Pat Hawker, G3VA reported (Amateur Radio
Techniques, Pat Hawker G3VA, 3rd ed, RSGB, p83) that Brian Booth,
G3SYC (SK ca. 2003), had used the 6JH8 beam deflection valve instead
of the 7360. Brian compared the two devices:
i) 6JH8 has a good deal more linear transfer characterisitic
ii) 6JH8 operates with the deflector plates at 0 volts, ie unnecessary
to bias to plus 25 Volts as per the 7360
iii) roughly similar transconductance 4400micromhos vs 5400micromhos
for the 7360
iv) 6JH8 has double the anode dissipation (3 watts)
v) then as now the 6JH8 is significantly cheaper.

The final comment was that Brian had used the 6JH8 as a receiver
mixer and also successfully as a mixer in transmitter circuits.

HTH and 73

John KC0G

Great info, thanks! But I wonder how he achieved DC balance with
the deflectors set for 0 volts?

Pete