[HBR] The long, SLOW HBR project

[Ian Wilson]

Walt wrote:


> Another possibility would be a higher IF -- say 5 to 9 Mcs -- and a ladder
> filter.   Those things are EASY to make -- four to six identical crystals
> and a handful of tiny caps -- and will equal just about anything out there.
> The higher frequency crystals would be easier for an HBR because you can
> more easily get the 2.8 or a bit more kcs of bandwidth needed to copy AM
> decently and one of the crystals probably can be pulled to act as a BFO.
>

I have found that tube BFO oscillators don't pull as easily as solid-state.
After all, you have far less gm to play with.

Using two crystals in a Super-VXO oscillator has worked well for me on
a couple of occasions when one crystal from an identical set wouldn't
quite stretch as BFO.

Great writeups. It is all too easy to forget all the painstaking steps that
lead from a receiver that is performing unpleasantly in some way to
a receiver that is a pleasure to listen to/operate.

73, ian K3IMW