To: rsgb_lf_group@blacksheep.org
Date: Thu, 21 Oct 1999 17:12:15 -0400
Subject: Re: LF: DAYTONG converters.
Message-ID: <19991021.171244.-73719.2.riese-k3djc@juno.com>
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From: "Bob RIESE" <riese-k3djc@juno.com>
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I have been building a converter using a Double Balanced Mixer and a 4
Mhz clock osc as a LO. The advantages is its ability to handle HIGH
levels of signals. I need to rebuild my RF amp  and have ordered the
parts to repair it.  { oops }

The mixer I am using is good from 2 Khz to 10 Mhz and I am using a 4 Mhz
IF. It is by Witkons, Johnson Co. and was free. Mini Ckts. has a similar
device for under 30 Dollars , the clock Osc is 2 dollars. If it works as
well as it appears to would be a minimum parts High performance
converter. Needs up to a +7 DBM for the LO and the Clock Osc is just at
the edge for that level of injection. I have had no spurs with it ,so far
but the RF stage went and I need to do more evaluation .

Oh,there are lots of options for the RF stage.

Bob K3DJC

On Thu, 21 Oct 1999 15:37:03 -0400 "Prof R. Jennison"
<boffin1@compuserve.com> writes:
>        About 2 weeks ago I mentioned an intense and troublesome 
>carrier on
>about 36 kHz which produced a very strong second harmonic on the ham 
>bandat 72 kHz.  From the strength of the second harmonic I deduced 
>that it was
>local but I could not locate it.
>
>        Since then I have done further tests and found that it is
>associated with the Datong converter.  The receiver used with the 
>converter
>was an ICOM 735.  I then tried it with an ICOM 740 but there was no 
>change.
> I then tried another Datong converter and the signal dissappeared 
>from 72
>kHz but appeared, as large as life, on 65kHz with a fundamental on 
>32.5
>kHz.  The only way that I can subdue it is to reduce the d.c. supply 
>to the
>converter to 3 volts but it is still faintly present.
>
>        The Datong converter is a bit of a "black box" with an 
>integratedcircuit at its heart.  I have no deails of this integrated 
>circuit and I am
>very puzzled by the phenomenon.
>
>        The 4th harmonic is also quite detectable and with some 
>converters
>it may well appear arround 136 kHz so it may be useful to us all to 
>find
>the solution.
>
>Can anyone help?
>
>73.
>Roger.  G2AJV.