[Milsurplus] RT-68/GRC - the continuing saga

[Glenn Little WB4UIV]

Jim

Your receive problem is probably because the IF is set for very wideband as 
is the transmitter. You can reduce the transmitter bandwidth by lowering 
the gain from the microphone. You can narrow the IF by removing the 
swamping resistors in each of the IF cans then retune the IF. IIRC the IF 
is stagger tuned for the wider bandwidth. By removing the swamping 
resistors, you increase the Q of each IF stage.

73
Glenn
WB4UIV

  At 01:09 PM 01/30/07, Falls, Jim wrote:
>I am working thru the main (complete) schematic for the RT-68 and have 
>discovered that the last portion of the schematic on the right is missing. 
>Looks like it tore off in the distant past. Can anyone send me a copy of 
>this portion? JPG/BMP is fine as long as it's readable.
>
>Still puzzling over the unmodulated carrier reports even though I hear 
>myself on the sidetone and with my 6M HT (Mic would have to be OK because 
>of the sidetone, correct?). Reception is still bad. Can hear myself if use 
>the HT in the shack, but I don't hear anyone else. All I have are AM 
>sig-gens. Any way to use one of them besides whanging on it and creating 
>"mechanical FM"? I suspect the receiver is badly out of alignment.
>
>Thought just occurred to me: everyone else in the net is using narrow-band 
>FM rigs. Maybe this is the root of the problem? The '68 has -+25 kHz 
>deviation. My HT runs at 2.5 (5 max). Maybe try a shack to shack QSO w/my 
>colleague who has the same gear? I did the initial RX/TX tests in his 
>shack and the '68 looked A-OK.
>
>Jim Falls
>KG6FWT
>Eureka, CA
>
>
>
>
>
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