[ARC5] Stable 2.0 MHz VFO.

[J. Forster]

Thank you Ken. I'll take a look.

Best,

-John

===============


> Hello, John:
>
> Yes. Building a VFO with the stability you mentioned in your e-mail
> for 2.0 MHz is not really much of a problem. The solution has been
> available since the late 1940s.
>
> In fact, the Heathkit VF-1, when properly built or rebuilt, is at
> least that stable at 160 meters. It outputs over the range 1.7 to 2.0
> MHz.
>
> There was a solid-state version of the device your require published
> in a recent issue of Electric Radio magazine, if you wanted to go
> that route.
>
> My Heathkit SB and HW "all-banders" are at least that stable and
> their VFOs operate at 5.0 MHz. When warmed up, they stay within a few
> Hz on all bands. My HW-101 (homebuilt solid-state) drifts back and
> forth about 2 Hz, and about 50 Hz from dead cold to warmed up. My SB-
> 301 and SB-401 (tube based) are about the same. My SB-102 (solid-
> state) drifts even less.
>
> There are at least two "secrets" to building such a device: 1) a well-
> wound coil using fairly heavy solid wire on a ceramic form, and 2) a
> really good double-bearing tuning capacitor. You should also be very
> careful of what kind of fixed capacitors you use in the circuit also.
>
> You might want to look at the Vackar circuit I have up on my website.
> It is unusually stable.
>
> http://www.w7ekb.com/glowbugs/VFOs/vackar_vfo.html
>
> Ken Gordon W7EKB
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