[Premium-Rx] 8711A A3 FL1 Filter Values

[Steve Pappin via Premium-Rx]

WJ-8711A Roofing Filter? There are three part numbers that were installed on A3, the 797006 RF Tuner, at location FL1. The first one is a 30 KHz filter and it is quite common. I'm speculating about the second two. The part numbers are on the schematic but there are no BW values assigned:

FL1 92609 = 30 KHz, 797006-1, -2, -3, -4

FL1 92699 = 8 KHz?, 797006-5

FL1 92727 = 16 KHz?, 797006-6, -7

Help identifying the second two would be valuable. I have not been checking to see which roofing filters were fitted in each radio. The final BW's are tabled in U12 so what you actually experience is the DSP assigned BW. 

Here's the logic:

1) Many versions of the 8711A were set up to search and decode so they had the wider roofing filters. A search receiver often needs a wider front end for use with a spectrum display unit. Data types to capture could be wide band, narrow band, or moving. A 30 KHz roofing filter could be valuable.

2) The HF-1000A has an 8 KHz roofing filter and targets voice reception in crowded bands.

3) Some 8711A's did not come with the sub-octave pre-selector. In these versions 8 KHz was an option.

Best Regards,
Steve

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