I have read every message that has been posted on this reflector for the
last two years. I have replied once I think. I just have to say one thing
about the R-390. When I was in the Navy, I was a Radioman, stationed at
Ship to Shore locations around the world, 80% of the time at a Naval Radio
Station, sitting in front of any radio that I, or any of my fellow radioman,
wanted to use during that watch. We had many choices of each type at each
location, as only receivers and receiving antennas were available, choices
of R-390's, SP-600's, 51S1's, some TMC (no Drake's) and others that I cannot
think of at this time. When it came to CW only, in bad propagation times,
interference from four or five other ships on the same frequency, and the
selective capability, the BEST of the BEST, was an AN/SRR-13 made by RCA, I
think. It used a projection frequency display, subminiature tubes, silver
plated modularized components, and was the most stable receiver I ever
encounter during that period.
On the R-390. It was best used by us to check a frequency generally for
RATT, MUX, SSB traffic ( in conjunction with an AN/CV-591???), and trying
to pickup Stateside AM Radio Stations! Generally it was terrible as a CW
receiver. On SSB is was better than the SP-600's, and about equal with the
51S1. The 51S1 saw more use as it was easier to QSY with. The SP-600's were
only used for RTTY with Two SP-600's and a diversity setup using two
AN/URA-8's with a comparator.
I had an SRR-13about 15 years ago, a tube went soft and could not get a
replacement. Dumped it. If only the internet was a reality then, maybe I
would still have it in use as my only receiver. I now use a Drake R4B with
an external DSP.
Any others out there have the same experiences, if so, let us all know.
Regards,
Monty/WB5GLB
-----Original Message-----
From: Larry L. Ravlin <sheepdip@continet.com>
To: Peter Chadwick <Peter_Chadwick@mitel.com>; 'igor rosky'
<irosky@yahoo.com>; 'amps' <amps@contesting.com>
To: <amps@contesting.com>
Date: Wednesday, June 02, 1999 7:39 PM
Subject: Re: [AMPS] radios/imd/intercept points
>
>Hi all,
>
>All of this is a moot point, show me a rcvr better than a Collins R390A and
>I will get it.
>
>Larry L. Ravlin AKA (Laurence the Magnificent)
>"Collins Equipt forever"
>Ham Radio Operator K0AEY
>Walterville, Or.
>sheepdip@continet.com
>
>"this is not a rice storage facility"
>
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>----------
>> From: Peter Chadwick <Peter_Chadwick@mitel.com>
>> To: 'igor rosky' <irosky@yahoo.com>; 'amps' <amps@contesting.com>
>> Subject: RE: [AMPS] radios/imd/intercept points
To: <amps@contesting.com>
>> Date: Wednesday, June 02, 1999 9:43 AM
>>
>>
>> Igor says:
>>
>> >secondly the receivers 3rd order intercept points
>>
>> Unfortunately, this still fails to address the fact that a high intercept
>> point in a receiver is totally useless without adequate phase noise
>> performance to go with it. A +20dBm third order input intercept point
>needs
>> at least -131dBc/Hz phase noise performance at the offset at which IMD
>is
>> measured.
>>
>> For a 10dB noise figure and SSB bandwidth, the noise floor is -140dBm. To
>> produce IMD signals at noise floor with a +20dBm TOIP, the inputs are at
>> -33dBm - that's about 5mV, which is a big signal - S9 + 40 on the 'usual'
>S
>> meter standard. In practice, noise at the antenna will be at least 10dB
>> above this.
>>
>> Admittedly, the number of IMD products is n(n-1)+ 1/2(n-1)(n-2) for a
>system
>> in which the front end bandwidth is less than a half octave, where n is
>the
>> number of input signals intermodulating. This does suggest a somewhat
>higher
>> intercept point is required than would be established just from
>> consideration of the highest level signals, while the phase noise
>> contribution is n times the number of signals. However, signal power
>> distributions show that there are relatively few big signals (which make
>the
>> most phase noise contribution), and more lower level signals which
>porduce
>> the IMD noise contribution. Thus there is justification for having the
>IMD
>> dynamic range equal to the phase nosie dynamic range. See my paper at RF
>> Expo, 1986.
>>
>> 73
>>
>> Peter G3RZP
>>
>>
>> --
>> FAQ on WWW: http://www.contesting.com/ampfaq.html
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>> Problems: owner-amps@contesting.com
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>
>--
>FAQ on WWW: http://www.contesting.com/ampfaq.html
>Submissions: amps@contesting.com
>Administrative requests: amps-REQUEST@contesting.com
>Problems: owner-amps@contesting.com
>Search: http://www.contesting.com/km9p/search.htm
>
>
--
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