BCD436HP/BCD536HP: Triple Conversion

Does anyone know if the BCD436HP has a Triple Conversion receiver? I am thinking of purchasing one of these scanners but not if it is not Triple Conversion,
.
Thank You

Del said:

Does anyone know if the BCD436HP has a Triple Conversion receiver? I am thinking of purchasing one of these scanners but not if it is not Triple Conversion,
.
Thank You

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I would be very surprised if it is not triple conversion, especially since it is a top of the line radio. My new Radio Shack PRO-652 is triple conversion as per the manual. The manual for your 436 does not show IF freqs.

Why would you reject a receiver because it's triple conversion or not? I have double, triple, and quadruple conversion receivers and to be honest, the doubles are the best performers, but not because of the conversion scheme, they are just better designs.I can think of a lot of reasons to pass on a .436 scanner, but none of them involve the conversion scheme. SD card issues, clock, USB jack failures. LED light failures, speaker issues, and general deafness on VHF high, yes. None of those problems involve how many conversions it has.

Double-injection design tends to have a much higher incidence of image interference than triple-injection. In some environments, it can make a very big difference. All ours are triple.

ratboy said:

and general deafness on VHF high

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The 436HP is definitely not the worst radio when it comes to this problem.

edmscan said:

The 436HP is definitely not the worst radio when it comes to this problem.

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Oh, I agree, I've had some others worse than the 436 over the years, but it's the worst one (Except for my former HP-1 when it got into one of it's "moods" that required resetting to hear almost anything) I've seen lately that wasn't an antique 30 year old+ scanner that probably needed alignment if not repairs. The worst one I ever have owned was a Radio Shack 50 Channel base scanner, can't remember the model number since I didn't have it long, but it was stone deaf on VHF, the local WX was barely breaking the squelch on it. On UHF, it was very good though.

Uniden seems to use the same IF structure in all of their recent digital scanners, including the X96xt, HP1&2 and the x36HP line.

1st IF @ 380/265Mhz (dual 1st IF's depending on the band being monitored) - Which are routed through either a 380Mhz or 265Mhz SAW filter (basically a ~10Mhz wide 'roofing' filter).

2nd IF 10.8Mhz - Which is routed through either a +-15Khz wide single pole crystal filter for FM, NFM and AM, or a +-100Khz wide ceramic filter for FMB/FMW).

&

3rd IF 450Khz - Which is routed through either a +-4.5Khz ceramic filter for FMN or +-9Khz ceramic filter for FM and AM. The x36HP is the only current Uniden scanner that incorporates separate 450Khz filters for FM/AM and FMN.

Edit - As for deafness on VHF, I have to agree that on the test bench, my 436HP is not quite as sensitive as my 996XT and 396XT.
But, what the radio lacks in raw sensitivity, it does make up for in improved S/n performance on NFM and digital systems, thanks to the true NFM filtering in the 3rd IF.

The sensitivity difference is only 0.15-0.2uV between the two models in my experience (on VHF anyway. There are other bands where the difference is greater).