Better look again. I believe the first beating occurs within the vfo to
produce the correct oscillator frequency for each band. The Triton and Omni
series worked the same way, the only difference being the 9mc vs 6.3mc IF.
Note I am anti Hertz when it comes to cycles!
Steve
N4LQ
----- Original Message -----
From: <WA4VEC@aol.com>
To: <tentec@contesting.com>
Sent: Tuesday, May 02, 2000 7:11 PM
Subject: [TenTec] Re: 580 Delta-was Receiver Lineage
>
> In a message dated 00-05-01 22:51:52 EDT, N4NT wrote:
>
> <<
> Well, I was apparently mistaken about the 580 Delta's IF scheme. I had
> thought it the same as the Corsairs -- knew it took different filters
from
> the older Omni's, but was designed to work the WARC bands without the 18
MHz
> spur.
>
> I may be mistaken about this, too, but thought the rebuild kits for the
> PTO's of the 580 Delta and the Corsairs were the same. Thought the
Tritons,
> older Omni's and Argosies were alike.
> >>
>
>
> I just looked at the manual for the Delta and technically it actually is
> double conversion. It mixes the input signal with output from a band
crystal
> to generate an 11.0 - 11.5 Mhz signal which is then beat against the PTO
> which goes from 5.2 to 4.7 Mhz to get the 6.3 Mhz final IF.
>
> You are correct in that the rebuild kits for the PTOs are the same since
they
> all use the same set of parts that come in the kit. The drive rod for the
> Delta is left threaded so that the frequency varies in the opposite
direction
> from the one in the Omni's. This is due to the 'upside down' mixing
scheme.
> Remember some of the old rigs where you tuned the dial one way on say 80
and
> in the other direction on say 20? This was due to the economy of using a
> single band crystal for both bands and adding it in one case while
> subtracting in the other.
>
> I agree that the other you mentioned are pretty much alike. I did not
like
> the inaccuray of the digital readout when I had my first Delta, but these
> days it doe not seem to matter for some reason.
>
> Walt
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