The Omni VII obviously works different than OII.
73,
Lee
-----Original Message-----
From: chacuff <chacuff@cableone.net>
To: Discussion of Ten-Tec Equipment <tentec@contesting.com>
Sent: Tue, Apr 24, 2012 10:17 pm
Subject: Re: [TenTec] 566 Orion II Firmware Version
V3.029---SpectrumDisplay&Tuning...
Bob something is missing here for sure.
If I do exactly what you say my "S" meter does not react the same.
That is
on my Orion II with the latest firmware and with the earler 2.044 and
also
my Omni VI+. Add attenuation and the meter goes down. On the Orion at
preamp and the meter goes up. It's not broken it's just different and
we
haven't identified why.
I agree with your assertion that that may be an ideal way for it to
work
because none of what you did with attenuation or preamplification
changed
the signal leve received at the antenna...but the fact is my rigs don't
work
that way.
Cecil
K5DL
----- Original Message -----
From: "Bob McGraw - K4TAX" <RMcGraw@Blomand.net>
To: "Discussion of Ten-Tec Equipment" <tentec@contesting.com>
Sent: Tuesday, April 24, 2012 8:35 PM
Subject: Re: [TenTec] 566 Orion II Firmware Version
V3.029---SpectrumDisplay&Tuning...
> According to Art Collins, generally credited with the adoption of the
S
> meter system, it was intended to give meaningful signal strength
reports.
> The old "green magic eye" on radios was a tuning indicator. Yes, the
> original value per my Collins 75A-3B manual shows S-9 = 100 uV.
>
> Sitting here this evening in front of my Omni VII listening to WWV on
10
> MHz, at 100% RF Gain the S meter indicates S-9 +6dB. Switching in
the
> ATTN
> in 6 dB steps to 18 dB the S meter stays at S-9 +6dB. The answer is
> simple.
> Add 18 dB of attenuation to the input, which automatically adds 18 dB
of
> gain to the S meter circuit. The opposite is true when the preamp is
> engaged. Add 12 dB of gain to the receiver circuit which
automatically
> adds
> 12 dB of loss to the S meter circuit. I refer to this as a smart S
meter
> system. SMART = Signal Measurement, Accurate, Reliable, True
>
> The Eagle, no matter what one does in terms of Attenuation or RF Gain
or
> Preamp activation, the S meter reading does not change. Again, same
> concept.
>
> Think about it, if you are receiving a station at S-9 + 20 dB and you
> switch
> in 18 dB of attenuation, did you change his signal strength at the
input
> of
> your radio? The answer is NO. You changed the signal at the input
to the
> receiver first stage. Then shouldn't the S meter always reflect the
> signal
> strength regardless of what one did to their receiver gain system?
Hence
> you can always be assured that the S meter system in the Tentec Omni
VII
> and
> Eagle will reflect the correct value at the input to the radio.
>
> Even with a signal at the input of -23 dBm or 15,811 uV which is 50
dB
> over
> S 9, reduction of the RF Gain to 0% the S meter does not change. It
still
> shows the signal at 50 dB over S 9, hence the system inversely adds
gain
> to
> the S meter circuit to make up for the reduction in RF Gain.
Therefore,
> the
> S meter is correct reading regardless of RF Gain setting. Of course
once
> you remove the 50 dB over S 9 signal with RF Gain at 0% you will see
the S
> meter display drop to 40 dB over S 9. The point being that the RF
Gain
> does
> not affect the accuracy of the S meter reading above AGC threshold.
>
> Now what one does see with no signal applied, as one reduces the RF
Gain
> the
> S meter moves upscale in 6 dB increments or 1 S unit. This reflects
the
> threshold of AGC reference to S 9 being 50 uV. At 100% RF Gain, as
one
> engages the ATTN function in 6 dB increments you will observe the S
meter
> indication move up scale 1 S unit per 6 dB. Now once reaching 18 dB,
> engage
> the Preamp and you will see the S meter move down scale by 2 S units
> indication that 12 dB of gain has been added.
>
> All of the math works and so does the radio respond accordingly.
>
> 73
> Bob, K4TAX
>
>
> ----- Original Message -----
> From: <k3miy@csonline.net>
> To: "Discussion of Ten-Tec Equipment" <tentec@contesting.com>
> Sent: Tuesday, April 24, 2012 11:10 AM
> Subject: Re: [TenTec] 566 Orion II Firmware Version
> V3.029---SpectrumDisplay
> &Tuning...
>
>
>> You're right, Ray. In the old days, the S meter was regarded as a
>> tuning aid, and nothing else.
>>
>> Ron
>> K3MIY
>>
>>
>> Quoting Rsoifer@aol.com:
>>
>>> Not only that, but the old Collins spec was 3 S units = 10 dB, not
the
>>> modern standard of 6 dB per S unit.
>>>
>>> More broadly, I'm afraid I just don't understand the continuing
>>> preoccupation with S meter and spectrum display issues. Neither
has
>>> much
>>> to
>>> do with
>>> performance, which is where I'd like to see T-T focus their
attention.
>>> Flak
>>>
>>> jacket on!
>>>
>>> 73 Ray W2RS
>>> _______________________________________________
>>> TenTec mailing list
>>> TenTec@contesting.com
>>> http://lists.contesting.com/mailman/listinfo/tentec
>>>
>>>
>>
>>
>>
>>
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>
>
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