NTSC demodulator?

[Inssomniak]

Could a tapped pc-r2500 use this device for NTSC demodulation?

http://www.usascan.com/files/tv5000.html

 

[gmclam]

That's what it looks like. You give the box 10.7MHz IF signal from your receiver, and it demodulates audio and video. One comment; most scanners are not programmed to tune to TV frequencies (although they certainly can receive in those bands).

 

[Inssomniak]

I believe a icom 2500 will tune to whatever I want it to tune to

 

[N_Jay]

I believe a icom 2500 will tune to whatever I want it to tune to

Does the 2500 have a wide enough IF bandwidth?

 

[obijohn]

Could a tapped pc-r2500 use this device for NTSC demodulation?

http://www.usascan.com/files/tv5000.html

It would depend on what the bandwidth of the first i.f. filter is. Most receivers only pass enough to demodulate f.m. broadcast. This narrow filter helps avoid overload and intermod problems in the next mixer stage.

To be able to have enough bandwidth to reliably demod. NTSC video, you would need a first i.f. filter that passes 5 to 5.5 MHz of spectrum at the tap point.

You will want to confirm from the tv5000 manufacturer that their product will work on your receiver. I don't have a service manual for the '2500, so I am unable to verify if this converter will work on your receiver.

 

[Inssomniak]

It has a selectable filter for the IF

FM mode 6khz, 15khz or 50khz.
WFM 50khz, or 230khz

http://wiki.radioreference.com/index.php/10.7_MHz_IF_Output_for_the_2500
I dont know if that means anything or not?

 

[obijohn]

It has a selectable filter for the IF

FM mode 6khz, 15khz or 50khz.
WFM 50khz, or 230khz

http://wiki.radioreference.com/index.php/10.7_MHz_IF_Output_for_the_2500
I dont know if that means anything or not?

The wike reference shows the 2nd i.f. section. You would need to confirm the filter bandwidth of the FIRST i.f. If the bandwidth is enough-that looks like a good tap point. It is before the 2nd i.f. filters.

Good Luck.

 

[naSTI]

I agree with the concerns others have voiced here. The bandwidth of the IF at 10.7Mhz is important. The TV-5000 was designed to operate with the discriminator out of the AR5000 (A,C and +3) models. You would need to know what the aggregate bandwidth of the IF stage you wish to tap on the 2500. I believe the bandwidth for the 5000 series is 5.5Mhz at 10.7Mhz, but cannot attest to this.

The TV-5000 has been discontinued and replaced with the TV1. Unlike the TV-5000, the TV1 is selectable for 5.5Mhz and 6Mhz IF bandwidths and costs almost twice as much. I wonder if the TV-5000 (or TV1 for that matter) can de-code/modulate AM (broadcast standard) and FM (private / security cams) formats?

naSTI