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R100 receiver sensitivity

Posted: Sun Dec 31, 2006 11:27 am
by Doug
A quickie question for the R100 gurus in the group. I'm taking an R100 down to the hammy bands for a friend. Once I got the station going and repeating I did some checking into some different output levels in the station receiver with the original alignment all looked good rx sens was at .374uv for 12db (could be better I'm sure) The original rx frequency was at 469._ _ _ I got the station reprogrammed and the new frequency is at 446.500 In doing the alignment the best I can get the rx to 135.89uv for 12db which as you know is unacceptable. I realize I'm taking it out of it's proper operating range and all but I wouldn't have expected the receiver to fall off as fast as it is. If this is a normal anomaly what have some of you done to over come this deafness. I can only imagine how bad it's going to get once it starts running through duplexers
Doug
And by the way Happy New Year Batlab members

Posted: Sun Dec 31, 2006 2:29 pm
by xmo
It should work fine.

The R100's shipped to the US normally would have the GLE6142A RF board which is specified for 438-470 MHz operation.

Did you follow the recommended alignment procedure?

Connect an 11 Meg ohm or greater impedance voltmeter to steering line test point [SL] and adjust C201 for a reading of 6.0 V dc.

Connect meter to LO test point and peak three cells of injection filter FL3 for maximum DC voltage. [typically 2.5 to 3.5]

Connect a 1 MHz or greater bandwidth ac voltmeter to the IF test point. Connect an RF generator to the RX antenna connector set to produce an unmodulated on channel signal sufficient to quiet the receiver. Adjust the RF generator for a reading on the voltmeter in the range of 10 to 30 mV rms.

Adjust the following coils for maximum indication, reducing RF generator output as necessary to keep voltmeter indication in the range of 10 to 50 mV rms.

FL1: beginning with screw closest to J1
FL2: beginning with screw closest to FL1
L51.

Finally, retune FL3