BCD536HP: I.F. 69.9225 mhz, really?

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AlphaFive

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I am in Asheville, I am utilizing my BCD536 HP in F.M. mode. I am scanning 335 to 399 MHz in a custom search, utilizing four steps, 5, 6.25, 7.50, and 8.33, in four custom searches. My antenna is a standard discone in my attic. At the top of this band, at 391.2525, I land on maintenance workers discussing tools, with a DPL of 047. This has all the signs of a mirror, I.F. issue. First, I look at the inverted DPL code chart I have, 047 converts to 023 DPL. That gives me a place to start looking. Now there are multiple formulas for finding an I.F. discrepancy. I have found several for my 536.
Based on the radio conversation, and a past history of a close strong signal blowing out my radios, I looked for a University of North Carolina Asheville U.H.F. system. I found it at 461.1750, WNUL903. I have this documented as a 023 DPL. I set my old Pro 197 in tune search mode to 461.1750. It was an absolute match for modulation. That equates to an I.F. of 69.9225 mhz. New one on me. So if your stumped on the 536 trying to figure out an I.F. discrepancy that makes no sense, try that one. Take care.
 

jonwienke

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You can change the IF frequency used in the x36 radios on a per-channel basis.
 

gary123

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It also could be a spur from the user if its a repeater. Rare but I have seen them.
 

Ubbe

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I think most scanners have strange mixing products when being close to a transmitter. Most, if not all, can be detected by switching the IF mode +/- or verify using a scanner of another brand.

/Ubbe
 
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