[TenTec]omni-d (genealogy) - the 580 Delta

Sat Dec 11 11:05:11 EST 2004

Ah yes, the first IF at 11-11.5 MHz. The 580 Delta is
an interesting design because the first LO is fixed,
the band crystal were chosen such that the 1st mixer's
output was in the 11-11.5 MHz range, the second mixer
was then fed the ~5.2-4.7 MHz PTO signal to arrive the
6.3 MHz IF. It was indeed a clever way to do things.
And as Steve points out it is the first (I believe)
Ten Tec Radio that did away with the RX preselector.

In addition to the audio AGC it's other significant
shortcoming was the lack of a RF gain control, while
receiver itself was decently quiet you couldn't do
anything about a noisy band like 80M in the summer
time. It also seemed to be a bit lacking in gain (not
so much sensitivity) on 10M. I really noticed this
when I used it as an IF for my DEMI 222MHz
transverter, the Corsairs did/do better as transverter
IF's for that reason. It was however the radio (along
with the DEMI transverter) that started me on my path
of using all transverters for all of my V/UHF weak
signal work. The signals were so much cleaner on the
Delta/DEMI combo than on any of the JA multi modes
that I was using on 50/144/432 at the time. Those JA
multi modes radios now live primarily on FM.

And not start a big fight ;) I always thought that the
proper nomenclature is "580 Delta" not "Delta 580". At
least the front panel lettering of my Delta is "580
Delta", though the manual cover is the other way
around...

Duane
N9DG

--- Steve N4LQ <n4lq at iglou.com> wrote:

> I believe you could consider the Delta 580 as
> TenTec's first Dual Conversion 
> receiver. The first IF was at 11mhz and the second
> was at 6.3mhz. The 11mhz 
> IF had a roofing filter with no optional filters
> available. I think this was 
> their only product built like this. This scheme
> eliminated the spurs on 17 
> meters plus some image problems found in the single
> conversion rigs, Omni, 
> Triton, Argosy etc. The 11mhz IF had very little if
> any gain and contributed 
> almost nothing to the noise therefore the 580 was
> one of the quietest 
> receivers around. The variable preselector was
> replaced by fixed passband 
> circuits for the front end. Unfortunately it
> retained the audio derived agc 
> design and with no RF gain control it suffered from
> the annoying pop on 
> strong signals with no easy means of compensation.
> 
> Steve N4LQ
> ----- Original Message ----- 
> From: "Duane Grotophorst" <n9dg at yahoo.com>
> To: <tentec at contesting.com>
> Sent: Saturday, December 11, 2004 10:02 AM
> Subject: Re: [TenTec]omni-d (genealogy)
> 
> 
> > Another radio to think about when pondering the
> Ten
> > Tec genealogy is the 580 Delta. It is rather
> unique in
> > that it did not use any 9MHz IF filters at all
> like
> > the 540/544, Omni's, Argosy's, Paragon and others.
> The
> > reason I bring this up is that the same 6Mhz IF
> > filters that were used for the 580 Delta later
> became
> > the second IF filters for the Corsair's, Omni
> V/VI's
> > and Paragon. So I have always thought of the
> Corsairs
> > and later analog-only IF Ten Tec models as being
> > somewhat of a homogenization of the original Omni
> > series and the 580 Delta, - for whatever that's
> worth.
> >
> > Duane
> > N9DG
> >
> >
> >
> > --- Carl Moreschi <n4py at earthlink.net> wrote:
> >
> >> Bill,
> >>
> >> This was done about a year ago or so on this
> >> reflector.  But I will try from
> >> memory to give the genealogy.
> >>
> >> After the Omni C, the main transceiver evolution
> >> continued as follows:
> >>
> >> Corsair
> >> Corsair II
> >> Paragon
> >> Omni V
> >> Omni VI
> >> Paragon II
> >> Pegasus
> >> Jupiter
> >> Orion
> >>
> >> There were of course many side branches for all
> the
> >> other transceivers.
> >>
> >>
> >> Carl Moreschi N4PY
> >> Franklinton, NC
> >> ----- Original Message -----
> >> From: <Able2fly at aol.com>
> >> To: <tentec at contesting.com>
> >> Cc: <n4py at earthlink.net>
> >> Sent: Friday, December 10, 2004 7:26 PM
> >> Subject: Re: [TenTec]omni-d (genealogy)
> >>
> >>
> >> >
> >> > Karl,
> >> >
> >> > Thanks for the history lesson (as far as it
> went).
> >>  Could you please carry
> >> it
> >> > a bit farther to include the Paragons, 
> Corsairs,
> >> and the ensuing  Omnis.
> >> If
> >> > it  hasn't been done already, it'd be nice for
> >> someone to compile a Ten
> >> Tec
> >> > time  line listing all the transceivers and
> their
> >> features. It'd be sad to
> >> see
> >> > the memory such a rich part of hamdom's past
> lost
> >> altogether.
> >> >
> >> > 73,
> >> > Bill   K3UJ
> >> >
> >>
> >
>
===========================================================
> >> > <Karl wrote:>
> >> >
> >> > The original Omni's were as follows:
> >> >
> >> > Omni A  - Analog  version
> >> > Omni D -  Digital version
> >> >
> >> > Then came the series B  modification which
> added
> >> two additional IF filter
> >> > slots, 30 meter receive and  an AUX band
> position.
> >>  So this made
> >> >
> >> > Omni A Series B - Analog  Version
> >> > Omni D Series B - Digital Version
> >> >
> >> > Later, TenTec had an upgrade  kit that added
> the
> >> 12 meter band to the AUX
> >> > position, and 30 meter transmit  to the above
> >> radios.
> >> >
> >> > Finally, the Omni Series C came out.  It was
> >> available only in digital.
> >> It
> >> > added the 18 mhz band, individual  selection of
> IF
> >> and audio filter, and
> >> XIT.
> >> >
> >> > 73,
> >> >
> >> > Carl Moreschi  N4PY

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