[TenTec] Receiver S meter values

Mon May 21 06:37:44 PDT 2012

My readings are taken with from the Panadapter screen and S-meter (which 
also displays dBm) of the FLEX-1500 which is a sub-receiver of my OMNI-VII 
(using the N4PY mod). Since the N4PY mod takes the sub-rx antenna input from 
the OMNI-VII's receiver (antenna input) loop, the signal is split between 
two receivers and is down 3 db to each receiver as a result.

Still the S-meters of the two receivers are very close when a signal with a 
constant carrier is received.

-----Original Message----- 
From: Bob McGraw - K4TAX
Sent: Monday, May 21, 2012 7:12 AM
To: Discussion of Ten-Tec Equipment
Subject: [TenTec] Receiver S meter values

I seem to believe that most companies accept  50 uV or -73 dBm at the
receiver input as the referenced signal strength for an S 9 meter
indication.  Moving up or down the scale, again most seem to agree that one
S unit is equal to a 6 dB change in signal strength.  Some earlier thoughts,
Collins for example, used 100 uV for S 9 in many of their receivers.

Starting with S -0  {what ever that might be}  we find that 0.10 uV or -127
dBm is a starting point.  Then S 1 would be 0.20 uV or -121 dBm being 6 dB
greater.  The scale moves up accordingly.  Do note that these are electrical
values and your S meter indication may be different.

73
Bob, K4TAX

----- Original Message ----- 
From: "GARY HUBER" <glhuber at msn.com>
To: "Discussion of Ten-Tec Equipment" <tentec at contesting.com>
Sent: Wednesday, May 16, 2012 8:17 PM
Subject: Re: [TenTec] Omni VII Filters

> Bob,
>
> You probably have the correct S-meter reading calculations..... I used to
> work with the commercial radio technicians and engineers (I was neither)
> who
> did all their signal level (power) calculations referenced to a milli-watt
> (0.001 W). I found that it was pretty easy calculate path losses or signal
> power levels once I understood the formula.
>
> See: http://en.wikipedia.org/wiki/DBm  dBm (sometimes dBmW) is an
> abbreviation for the power ratio in decibels (dB) of the measured power
> referenced to one milliwatt (mW).
>
>
> 73 ES DX,
> Gary -- AB9M
>
> -----Original Message----- 
> From: Bob McGraw - K4TAX
> Sent: Wednesday, May 16, 2012 7:18 PM
> To: Discussion of Ten-Tec Equipment
> Subject: Re: [TenTec] Omni VII Filters
>
> If I did the math correct, Gary's reference to dBm would be, for -30 dBm
> is
> about S-9 +43 dB, and for -10 dBM would be S-9 +60 dB or so.  Nice strong
> signals I'd say.
>
> 73
> Bob, K4TAX
>
>
> ----- Original Message ----- 
> From: "GARY HUBER" <glhuber at msn.com>
> To: "Discussion of Ten-Tec Equipment" <tentec at contesting.com>
> Sent: Wednesday, May 16, 2012 7:13 PM
> Subject: Re: [TenTec] Omni VII Filters
>
>
>> The OMNI-VII disadvantage MAY have a lot to do with the RF gain setting
>> of
>> the OMNI-VII and the PAs and transmitted signals of TX A, B, C, ....
>> Our local club has for years had many and often heated discussions over
>> the
>> CW, SSB, or Digital station being heard by the others on different bands.
>> The one exception was the year we ran three OMNI-VI+ for FD.
>>
>> With my OMNI-VII, I have both the 300 and 500 Hz filters installed and
>> seldom notice my neighbors AC9S and AA9LC unless they are within the
>> OMNI-VII's passband. AC9S is very active in both DXing and Contesting
>> with
>> an ORION-II, Alpha amp and SteppIR beam. We both typically run our TenTec
>> transceivers with minimum RF gain and have found we can co-exist on the
>> same
>> band and mode as long as we avoid transmitting within 3 KHz of each
>> other.
>> Typical signal levels received on my OMNI-VII (and Flex-1500 sub-rx) from
>> AC9S are -30 to -10 dBm depending on the frequency and the antenna used.
>>
>> 73 ES DX,
>> Gary -- AB9M
>>
>> -----Original Message----- 
>> From: Richards
>> Sent: Wednesday, May 16, 2012 6:14 PM
>> To: Discussion of Ten-Tec Equipment  of each Subject: Re: [TenTec] Omni
>> VII
>> Filters
>>
>>
>>
>> On 5/16/2012 8:58 AM, Rick - DJ0IP / NJ0IP wrote:
>>
>>> The one place where the OM7 will be at a disadvantage is if you are
>>> trying
>>> to use it at a multi-multi station where you have at least 6 max legal
>>> power
>>> stations on the air simultaneously from a location the size of a
>>> football
>>> field,
>>
>>
>> I disagree based on experience.    We run  2
>> Omni VIIs, an Orion II, an Omni VI, all in the same
>> room, and it is someone using a K3s that complain !
>> For some contests, the phone guys are in one place,
>> and the CW guys are 300 yards away on a big hill
>> in a field and the guys with the Elecraft gear complain
>> about intermod, not the TT guys.   (I hope this does NOT
>> start a sub-thread about TT v Elecraft...)
>>
>> Of course you gotta use passband filters, and stay off
>> the same antenna ...    ;-)   ...  but I have NEVER
>> had intermod, interference, of any RF on my anything
>> under such extreme conditions.
>>
>> Shoot, Rick... it might be better than you think !   ;-)
>>
>>
>>
>>> Don't tell anyone I said this, but I even like it a wee bit better than
>>> my
>>> Eagle, but the Eagle has other advantages - size, weight, and
>>> simplicity.
>>
>>
>> YES - The design team at TenTec obviously thought
>> about what to put on the Eagle and what not to ...
>> trying not to obsolete any of the other products in
>> the line.  I prefer the Omni VII over the Eagle because
>> it has more stuff on it... such as a receive only
>> antenna jack,  two transceive antenna jacks, etc.,
>> but the Eagle presents a high performance option,
>> at a lower price for guys who don't want all that
>> extra jazz.
>>
>> I have considered using an Eagle as a "second receiver"
>> for the Omni VII, and letting Carl's N4PY Pegasus
>> control program integrate the two as one - so I could
>> use the band scope display for the Eagle to work as
>> a panadatper for the Omni VII - click on it scope, and
>> both rigs tune to the same frequency.   Cool.   I use
>> a TT RX-320D for that now, but the Eagle would be
>> way better I think.
>>
>>
>> One of our Lunch Bunch guys is older than the sun,
>> and sometimes talks about getting out of ham radio
>> because it seems to be getting too complicated for
>> him -- so I keep recommending the Eagle because I
>> think it would be a huge performer, but a much
>> easier rig to run than the rest of the crop.  He could
>> easily take it to Florida when he goes down for the
>> Winter.   Stubborn old coot... but he is a great guy!
>>     ;-)
>>
>>
>>> *The exception would only be a top notch 160m operator with great
>>> antennas
>>> in a 160m contest.  The rest of the time, the rest of the contests, the
>>> operator makes far more difference that the tiny bit of difference in
>>> the
>>> radios.
>>
>>
>> We used an Omni VII to work the CQ WW
>> contest... and came in 1st in Michigan... 1st in
>> Section 8...  Fifth in US... 7th in North America...
>> and the only guys to beat us were all on the East
>> Coast with a slightly better shot at EU multipliers.
>> So, I am not worried about using the Omni VII in
>> a 160 meter contest.
>>
>>
>>
>>> In my books, the Omni VII is the best all-around radio on the planet
>>> today
>>> for 98% of all hams.
>>
>>
>> That might be a slight exaggeration... the real
>> figures is closer to 95% of all hams...       ;-)
>>
>>
>>
>> ======================  JHR  =======================
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