[HBR] Radio design advice

[N2EY at aol.com]

In a message dated 5/30/06 1:20:41 PM Eastern Daylight Time, 
windy10605 at juno.com writes:


> What I've come up with as the best alternative so far is something like
> the Simple-X receiver of the early 60s handbook using a tuned preselector
> covering both 40/80m (pluggable coil), a  Heathkit HW/SBxxx VFO for
> tuning 5-5.5Mhz (36:1 vernier), both feeding a mixer with audio derived
> AVC ? Mixer output is a tuned 1843Khz IF coil with a 1843Khz crystal
> filter (cheap), driving a regenerative detector (no BFO required), and
> that drives 2 stages of audio. 
> 

6SL7 or 6SN7 Pullen mixer
6SL7 or 6SN7 oscillator/buffer a la W2YM, with Command set tuning cap
Xtal filter
6SK7 IF 
6SA7 product detector/BFO
6SL7 or 6SN7 audio (2 stages)

6J5 is equivalent to 1/2 6SN7. 6C5 may be close to 1/2 6SL7. 12 volt heater 
tubes can be used as well.

If Pullen mixer is not wanted, use 6SA7 or 6SB7 pentagrid (6SB7 preferred). 
If W2YM VFO is not wanted, use 6SK7 in Hartley circuit.

The Heath LMO does not have a built-in vernier - the basic LMO module takes 5 
turns to cover 500 kHz - way too fast. They're also not the easiest thing to 
find without buying the whole rig, and you wind up with a lot of metalwork.

The easiest way to use the ARC-5 tuning capacitor is to use it in a cut-down 
transmitter chassis. There was an article in CQ called "A Low-Cost VFO" by 
W2EWP that gives the mechanical details. The article also appears in the "Command 
Sets" book which is free for the download from pmillet's site IIRC.

You need a BC-457 or BC-458, but only the VFO part and the tuning caps need 
be intact.  

73 de Jim, N2EY