How bout that fan on the 963 switcher.......the first time I heard it I
though some kind of aircraft was headed my way! Toby W4CAK
----- Original Message -----
From: "Steve Baron - KB3MM" <SteveBaron@StarLinX.com>
To: "Discussion of Ten-Tec Equipment" <tentec@contesting.com>
Sent: Friday, July 15, 2005 3:49 PM
Subject: Re: [TenTec] Fw: Cooling fans and IF gain
> Interesting.
>
> I got the TT 963 supply with my Orion. I was surprised the first time its
> fan turned on. Just sitting on the desk with the Orion in RCV, the fan
will
> run once in a while.
>
> ----- Original Message -----
> From: "Mike Coogan W7MGC" <mikegc@pacifier.com>
> To: <tentec@contesting.com>
> Sent: Friday, July 15, 2005 18:09
> Subject: [TenTec] Fw: Cooling fans and IF gain
>
>
> > I noticed the same heat build up on the 962 p.s. for my Omni 6+ when
> > running Rtty. I mounted a TT 310 fan on the heat sink of the power
> > supply, powered from the 12v dc outlet on the p.s.
> >
> > Mike W7MGC
> > Vancouver, Washington
> >
> > Omni 6+ >>253 Auto Tuner>>HercII amp, Love it!
> >
> >
> > ----- Original Message -----
> > From: "Robert & Linda McGraw K4TAX" <RMcGraw@Blomand.Net>
> > To: "Discussion of Ten-Tec Equipment" <tentec@contesting.com>
> > Sent: Friday, July 15, 2005 6:08 AM
> > Subject: Re: [TenTec] Cooling fans and IF gain
> >
> >
> > > Interestingly enough, the Omni VI+ PA is rated at 100% duty cycle
> > > while the
> > > 961 power supply is not. I've found that additional cooling on the
> > > power
> > > supply is necessary in high duty cycle modes, partly caused by the
> > > bridge
> > > rectifier being mounted to the bottom plate for heat dissipation. A
> > > small
> > > 12V fan blowing on the heat sink in the rear takes care of the
> > > problem.
> > > Also, one might take note that if the power supply is sitting flat on
> > > the
> > > desk there is little room at the bottom rear for vertical air
> > > convection.
> > > If possible, elevate the power supply, allow the heat sink to hang off
> > > of
> > > the rear support and allow the heat sink to have more "breathing
> > > room".
> > >
> > > As to the Omni VI+, I've found that heat build up within the radio
> > > does
> > > cause some frequency drift primarily due to BFO frequency changes. I
> > > changed my BFO's to TXCO's and found a nice improvement. All in all,
> > > probably not worth the investment, time and effort, for such a small
> > > benefit.
> > >
> > > I've read cases where one removed the speaker, replaced it with a
> > > computer
> > > type 12 V fan that made improvements of about the same magnitude to
> > > the
> > > radio. This would be a lot less work and a lot less $$.
> > >
> > > 73
> > > Bob, K4TAX
> > >
> > >
> > > ----- Original Message -----
> > > From: "Chuck Guenther" <ni0c@earthlink.net>
> > > To: <tentec@contesting.com>
> > > Sent: Thursday, July 14, 2005 8:17 PM
> > > Subject: [TenTec] Cooling fans and IF gain
> > >
> > >
> > >> N6KB wrote: "I find that operating my Omni VI in CW contests a fan on
> > >> the
> > >> PA heat
> > >> sink is necessary. My Kenwood TS-440 has a built-in fan with
> > >> temperature
> > >> controlled speed, or at least duty cycle. The TS-440 receiver
> > >> performance in contest conditions does not compare to the Omni VI
> > >> though. I wish Ten-Tec would have included a built in fan. I have
> > >> never
> > >> tried, or thought that I needed, a fan to ventilate the insides of
> > >> the
> > >> Omni VI though."
> > >>
> > >> I used a TS-440S for about seven years (in fact I still have it).
> > >> The
> > >> only time the cooling fan ever came on was during an RTTY contest (I
> > >> was
> > >> running about 60 watts). It never came on when operating CW or SSB.
> > >>
> > >> With the Ten Tec rig, I find the heat sink of my 961 PS always runs
> > >> at a
> > >> higher temperature than the Omni 6 PA heat sink.
> > >>
> > >> Today, in order to alleviate my gain problem, I swapped out the Ten
> > >> Tec
> > >> 221 filter for the INRAD 753 (which has a few dB less insertion
> > >> loss).
> > >> The gain seems adequate (and more stable) now, so perhaps my problem
> > >> was
> > >> in the filter, or the connections thereto.
> > >>
> > >> 73,
> > >> Chuck NI0C
> > >> .
> > >> _______________________________________________
> > >> TenTec mailing list
> > >> TenTec@contesting.com
> > >> http://lists.contesting.com/mailman/listinfo/tentec
> > >>
> > >
> > >
> > > _______________________________________________
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> >
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> >
>
>
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