Hi Doug, et al--
If you are speaking of my posts about spurious outputs in the Ten-Tec Omni-B
rigs, THE PROBLEM OCCURS ON THE 17 METER (18 MHZ) BAND. Call Ten-Tec again
and ask them about that. You will need to find someone who remembers the
Omni-B (probably Garland Jenkins and Larry Wirth are your best bet).
Neither I nor anyone else has said anything about a problem with the 30
meter (10.1 MHz) band since I've been reading this reflector, some 18
months.
Sorta bothersome to be misquoted and then contradicted.
73 de Mike N4NT@wireco.net
----- Original Message -----
From: dslosty <dslosty@pipeline.com>
To: <tentec@contesting.com>
Sent: Wednesday, May 12, 1999 7:20 AM
Subject: [TenTec] Omni D version B, 30 meter mods
>
> In the past on this reflector, there's been various comments
> saying that the Omni D version B (model 546B) can not be put onto
> 30 mtrs due to its crystal mixing scheme and resultant spurious
> emissions.
>
> Two calls to Ten-Tec counter that.
> The tech/repair dept says that many were modified to work on 10MHz
> transmit
> but that due to the age of the rig, the parts are no longer available.
> The coils, etc are no longer being made and the stocks are depleted.
>
> I was rather annoyed by their attitude when I asked if the component
> values were available. Their claim was that the info was discarded, etc.
> They seemed to feel, (as to the Japanese companies) that I shouldn't
> expect
> detailed support for a rig "that old".
>
> In any event, I did some experiments. As originally configured in the
> 10 Mhz position, the low power band-pass-filter is left open in
> the 10MHz position. The RF output lowpass filter is jumpered straight
> thru, allowing 10MHz receive.
>
> I jumpered the 14MHz low pass filter to the 10MHz postion and tried
> using
> the 7MHz BPF and then the 14MHZ BPF. RF output on 10MHz was around 5
> watts using the 14MHz BPF and around 30 watts using the 7MHz BPF.
> When the BPF was jumpered straight thru, output rose to 100 watts.
> Thus the 14MHz LPF works well and should suppress the 2nd and higher
> harmonics
> of 10MHz. The only apparent problem is the BPF.
>
> Does anyone know the component values (coil inductance or overcoupled
> transformer
> values, etc) for the low power Band Pass filter? Apparently a parts kit
> was
> sold for over 10 years.
>
> With the proper BPF function, the 546B should meet spurious emission
> specs.
> Again, Ten-Tec apparently modified many of them.
>
> Better yet, anyone have one of the old kits lying around that was never
> installed??
>
> If all else fails, I'll try to design my own band-pass filter....
> I currently don't have access to a spectrum analyzer so complete testing
> is
> difficult.
>
> 73,
> Doug/WA1TUT
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