[Boatanchors] cw chirp

Sun, 19 Jan 2003 09:43:56 -0500

In this case I would suggest using Zener diode regulation for the VFO.
1. Old regulator tubes are really not all that stable; they do wear out.
Even NOS is questionable. I found that out the hard way a few years ago with
an amplifier screen supply.
2. Adding another socket and tube is intrusive and time consuming
3. SS is simple, easily reversible, unobtrusive AND works a lot better.

Zeners are available at www.mouser.com.

I have changed to Zener regulation in numerous TX/RX oscillator circuits and
have been pleased with the results.

OTOH, chirp is traditional, and lets others know you have a real radio (:

Carl
----- Original Message -----
From: "Glen Zook" <[email protected]>
To: "Michael Stoller" <[email protected]>; <[email protected]>
Sent: Saturday, January 18, 2003 4:13 PM
Subject: Re: [Boatanchors] cw chirp

> First of all, are you trying to key the VFO along with
> the transmitter?  If so, the definite tendency is to
> chirp.  Let the VFO run continuously when sending CW,
> turn it off only when receiving.
>
> Secondly, if you are running the HG-10 from the DX-60
> internal supply then this often results in chirping.
> I don't have the schematic for the HG-10 handy, but if
> it is like the VF-1, then the regulator tube only
> controls the screen of the oscillator tube.  What you
> can do is to add an OB-2 (105 volt regulator tube) in
> series with the existing 0A-2 but change this to an
> 0B-2.  Run the 300 Volts B+ from the DX-60 through a
> small dropping resistor to the first 0B-2 and leave
> the 2nd 0B-2 in to regulate the screen.  This gets
> regulated B+ on both the plate and screen of the
> oscillator and helps keep it from chirping.
>
> A better way is to run the VFO from a separate B+
> supply and leave the B+ on all the time.  Use a set of
> relay contacts to key the VFO when you go to transmit.
>  This keeps the heat level pretty constant in the VFO
> and the separate B+ supply won't vary with the
> transmitted power of the DX-60.
>
> Glen, K9STH
>
>
> --- Michael Stoller <[email protected]> wrote:
> > Just put an old DX 60, HG-10 VFO and my trusty ol SX
> > 100 on the air. All
> > indications are everything is working .However,
> > reports indicate the CW note
> > chirps.
>
> =====
> Glen, K9STH
>
> Web sites
>
> http://home.attbi.com/~k9sth
> http://home.attbi.com/~zcomco
>
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