Old scanner vs New ( Reception)

[np4r]

Hi , I bought a Vertical antenna for 800mhz , when istalled it was just receiving a local P25 police system nothing else with my TRX-2 . Yesterday I took out an old Pro-433 scanner with the same antenna /location and it start receiving different control channels including one in EDACS thats is far from here but again in my Trx-2 nothing received as in pro-433 . Is this reception problem with the TRX-2 , maybe I have to do some settings in it ? ot just is not to good in reception compare to others ? Thanks for the help !

 

[bob550]

I would have to guess that there may be some setting that can improve your P25 reception. Modern digital scanners are far more technically complex than older analog models. It used to be that all you had to do was to program your choice of frequencies into channels within banks, and enjoy. No tweaking was necessary. Then too, there can be variances in receiver sensitivity across different brands and models which would affect reception. You should also check to ensure you don't have attenuation activated globally. That said, you may be best by having a Mod move this thread to the Whistler forum where you'd find more helpful responses.

 

[Whiskey3JMC]

Too many variables to make a definite determination. Is the antenna tuned exclusively for 800? Is the squelch set low enough on the TRX-2? Best way to rule out an RX problem or possible programming errors would be to tune into a NOAA weather repeater on the problematic scanner. If it comes in loud and clear then RX sensitivity may not be the issue (at least on VHF). For 800mhz, switch to tune mode & enter the control channels of the sites you can't receive. Do they display site data?

 

[np4r]

Yes is a 800mhz antenna (824-896) the Squelch is set low (trx-2) , I can tune the noaa freqs in vhf loud and clear with the vertical , but when i go into tune mode the control channel go in silence , sometimes it shows all the signal bars with an S but no audio/data.

 

[bryank104]

I have a TRX2 scanner. It works fine on vhf uhf. But 800MHz it doesn’t pick up a simulcast system. I have number of Uniden scanners and they pick up the system, even a 996T. I have tried all the settings, read all the post here concerning the TRX2 but i can not get it to receive the simulcast system. Yes I’ve used outside antennas and assorted inside antennas. To no avail. I going to send it back to whistler to see if there is a problem with the scanner

 

[eorange]

I've found that older scanners have better sensitivity, likely because they don't have all the filters in newer digital radios.

 

[Ubbe]

You would want to have as much filters as possible in a scanner to narrow the frequency range it sees for each filter.

But the TRX seems to be very picky about it's frequency being spot on to be able to receive simulcast systems. My TRX-2 are 1KHz off at 400Mhz and that might create some sort of heterodyn low frequency tone when trying to receive several towers that transmit on the exact same gps controlled frequency.

I haven't looked closely enough in the scanner to be able to see if there's some sort of master oscillator that can be tuned. If it where such an adjustment it would need you to monitor the same frequency with another working scanner and then tune the TRX with extreme care up and down in its tuning until it starts to decode the signal when the other scanner are decoding it sucessfully. If a scanner have a frequency tolerance of 1ppm then it is allowed to be 800Hz off at 800Mhz and that might too much for simulcast reception. Neither Whistler or Uniden state any frequency tolerancies, and the SDS scanners haven't even got any sensitivity data as that change with the location, so you cannot complaint that a scanner are out of frequency calibration and have it retuned for free at the factory, even if it means that it would receive simulcast systems so much better if it had been fixed.

/Ubbe