[Premium-Rx] The "Sound" Of Receiver IF Amplifiers

[Carcia, Frank A. HS]

You forgot No Processor noise.

-----Original Message-----
From: Gary Follett [mailto:gfbike at iaxs.net]
Sent: Thursday, October 09, 2003 8:40 AM
To: A. Lal
Cc: premium-rx at ml.skirrow.org
Subject: Re: [Premium-Rx] The "Sound" Of Receiver IF Amplifiers


I don't know where people get their information but the receiver in a 
TR 7 is very much the same as a TR7 (though not exactly). The 
synthesizer is exactly the same as the TR7, as is the up converter 
board, the front end filters, the second IF (except that the R7 allows 
for 5 filters instead of the TR7's 4). The power supply of the R 7 is 
radically different because the receiver operates from 110 VAC instead 
of 12 VDC. As you  noted, the R7 also has an RF preamplifier, though it 
only needs this when you use the radio with antennas such as a 
Beveridge or a shielded loop. Otherwise, the receiver has more than 
enough sensitivity (as does the TR7)

The singular most important difference between the R7 and the TR7 is 
the use of the 50 KHz last IF stage. This low frequency IF allows the 
inclusion of a T Notch filter for nulling out strong heterodynes. Being 
inside the AGC loop, this notch is far more effective than any outboard 
DSP filter or any other type of Notch Filter.

Sonically, IMHO, the audio of the R7 is not different from a TR7.

I would not have owned 8 TR7's plus the R7's I had if I did not feel 
that their performance merited it. My only beef with the "7" line ever 
has been the receive audio, which you pointed out is not the major 
issue with a DX receiver.


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