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Whistler TRX-2 vs. Uniden SDS-100: Which Receives Better in P25 Multi-Cast Environment?

What's Your Favorite Brand Of Police Scanner?

  • Whistler/Gre/Radio Shack

    Votes: 10 20.8%
  • Uniden Bearcat

    Votes: 35 72.9%
  • Some Other Brand

    Votes: 3 6.3%

  • Total voters
    48

SteveSimpkin

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I'm sure the TV's have something built in to emanate a special RF signal otherwise that van would be picking up a lot of other RF that wasn't TV's.
I think it is more likely that they have specialized receiving equipment that is looking only for the signals given off by the TV set as a side effect of the receiver design (local oscillator, HV flyback transformer, etc) while filtering out any other signals that may be present in the surrounding environment.
 

kruser

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I think it is more likely that they have specialized receiving equipment that is looking only for the signals given off by the TV set as a side effect of the receiver design (local oscillator, HV flyback transformer, etc) while filtering out any other signals that may be present in the surrounding environment.
This was always my understanding how they did it.
 

kruser

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There was a lot of it going on years ago but could probably not be done on modern digital tv sets.
I would suspect the same but after reading the Wiki link that SteveSimpkin included, I'm no longer sure they are not still doing this as it does have mention of more modern LCD sets still being able to be detected. It sounds pretty far fetched to me though.
TV detector van - Wikipedia
 

KevinC

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Somewhere other than home :(
I would suspect the same but after reading the Wiki link that SteveSimpkin included, I'm no longer sure they are not still doing this as it does have mention of more modern LCD sets still being able to be detected. It sounds pretty far fetched to me though.
TV detector van - Wikipedia
We're getting off-topic here, but a story I read from the 60's stated that almost all cases of people being caught without a license was due to a nosy/jealous neighbor or the government going around and just hearing TV's via an open window.
 

Daleb49

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Parma, Ohio
I don't think the squelch level comes into play or have any effect with P25 digital reception.
Well on my TRX-1 if I have the squelch turned on full I don't hear any voice at all on my local P-25 system.
If I set it at about 9 o'clock I get voice back.

So in my case it does have an effect.
 

DoctorZ

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Well on my TRX-1 if I have the squelch turned on full I don't hear any voice at all on my local P-25 system.
If I set it at about 9 o'clock I get voice back.

So in my case it does have an effect.
I run the squelch as low as possible on my TRX-2, but I do need to have it up enough to enable scanning of NOAA Weather Radio when traveling on a Storm Chase. :)
 

Ubbe

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Stockholm, Sweden
Both Uniden and Whistler uses the squelch to detect if it is a carrier on the frequency and only then stops scan and starts to try to decode a digital signal. If the squelch are set to 0 it will think it is a carrier on each frequency and will spend time trying to get some data and scan rate will be ridicuosly slow. If the squelch are adjusted too high it will just skip over weak channels and not stop on them. If you turn the squelch up on a Uniden BCD536 and then down again it will open squelch on the 1 setting on an empty channel and then close again at 2, which is an excellent squelch handling. Whistlers TRX2 on the other hand will open squelch at 4 when turning it down and not close again until the 8 setting. It is a big differense in signal level between the two settings, the hysteres is too high, which makes it difficult to use a TRX2 without missing some of the action that the Uniden scanner manage to monitor.

/Ubbe
 

VK3RX

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I would suspect the same but after reading the Wiki link that SteveSimpkin included, I'm no longer sure they are not still doing this as it does have mention of more modern LCD sets still being able to be detected. It sounds pretty far fetched to me though.
Certainly still possible, and being done.

Some of the radiation would come from the set itself, and some can be radiated by the feed system and antenna.

It is why military radios and other gizmo's they use have high suppression of such radiation, to prevent detection by the opposition :)
 

djs9164

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Dec 14, 2012
Messages
51
I keep seeing the Whistler unit being compared to the SDS series. The Whistler was never supposed to compete with that series. A more accurate comparison would be to compare the TRX2 to the BCD 536, or even compare the 536 to the SDS series. Not so much a Whistler fan boy but I think apples should be compared with apples.


Sent from my XT1635-01 using Tapatalk
 

DoctorZ

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Messages
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I keep seeing the Whistler unit being compared to the SDS series. The Whistler was never supposed to compete with that series. A more accurate comparison would be to compare the TRX2 to the BCD 536, or even compare the 536 to the SDS series. Not so much a Whistler fan boy but I think apples should be compared with apples.
What I originally set out to do was show that Uniden's alleged "True I/Q digital tech" was a scam to sell their product. We were all waiting for Whistler to come out with their "True I/Q" equivalent scanner only to have them cancel it. My theory was that Whistler was JUST AS GOOD as Uniden at decoding digital signals and Uniden was simply using a Marketing ploy by calling their digital decode something "new."

The video was actually the first time I had ever had both scanners running together side by side. My original plan was to run the Whistler on the beam antenna then run the SDS100 on the beam antenna to show that the signals were being decoded just as well by both scanners.

It came as a huge surprise to me that even with the Whistler hooked up to the beam 60' in the air, the Uniden was picking up more signals than the Whistler with just it's rubber duck. This was even more impressive considering that I live in a literal forest of 1500 70' tall oak trees surrounding my house! It would be safe to say that the Uniden was picking up a lot of those weak signals on reflection bouncing around in my woods.

This sold me on the Uniden and converted me over to their scanners, which I've always hated in the past.
 

trentbob

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Bristol, Pa.
So maybe I missed this but did you try the SDS with the 60 ft antenna? As others have said here in so many words you're comparing apples to oranges. Or should I say worm filled crab apples to Fresh blood oranges.
 

sibbley

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Nazareth, Pennsylvania
You probably have some funky RF situation at your place. Whistlers TRX scanner close squelch first at a 8 setting but usuable levels are 9 or 10.

/Ubbe
I normally run my TRX 2 squelch at 11 while scanning different systems. In my case anything below 11 will result in very slow scanning and missed transmissions. If I'm monitoring a single P25 system, squelch set at 8 works great.
 

Ubbe

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Stockholm, Sweden
It's difficult to see the scan speed on a TRX scanner. A Uniden displays live what system and departments it is actually scanning but a TRX just lists the scanlists you have enabled and have no relation to when the scanner switch from one scanlist to the next. I used an RF signal generator to check analog conventional scan speed and it was something like 50ch/s on my TRX-2. Scan speed of trunked systems depends mostly on how many voice channels are active that needs to be analyzed and the dwell time set.

Interesting about the squelch level. If you remove the antenna and step down the SQ level to 5 and then 4, will it open there? And if you turn the squelch up will it close at 8 or 9 without any antenna connected? If it does then the different values with an antenna could indicate a strong interfering signal. The quality of a TRX's front-end are not one of the best.

/Ubbe
 

DoctorZ

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So maybe I missed this but did you try the SDS with the 60 ft antenna? As others have said here in so many words you're comparing apples to oranges. Or should I say worm filled crab apples to Fresh blood oranges.
I never got that far. The SDS was kicking butt with just it's rubber duck against the Whistler which was on the 60 ft antenna, there was no longer any need to attach it. If I did, I would have been accused of overloading the SDS's front end.
 

trentbob

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Bristol, Pa.
Yep, not exactly sure what you're listening too but you may find if you listen to VHF hi or other conventional frequencies your antenna will overload both radios.

If you're listening to a P2 simulcast system 50 miles away you will love the Rooftop for that system on the SDS. Fine-tuning your filters will also make a difference.

They are dramatically different radios by Nature with the rebranded GRE being quite ancient technology and the SDS being the latest.

Have fun
 

DoctorZ

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Feb 14, 2005
Messages
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Location
Minnesota, USA
Yep, not exactly sure what you're listening too but you may find if you listen to VHF hi or other conventional frequencies your antenna will overload both radios.

If you're listening to a P2 simulcast system 50 miles away you will love the Rooftop for that system on the SDS. Fine-tuning your filters will also make a difference.

They are dramatically different radios by Nature with the rebranded GRE being quite ancient technology and the SDS being the latest.

Have fun
The 60' beam is a 700 MHz to 900MHz antenna. It will NOT overload any radios in the VHF, UHF, or any other conventional frequency bands as it's not tuned for them. It does have a 2-Meter omni stick on the back end that acts as a reflector for the 800 MHz and an omni on VHF. I've got it all covered.
 

pro106import

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It's difficult to see the scan speed on a TRX scanner. A Uniden displays live what system and departments it is actually scanning but a TRX just lists the scanlists you have enabled and have no relation to when the scanner switch from one scanlist to the next.

/Ubbe
Hey Ubbe, try using the "Control Demo" program that Whistler has. Free software you can download from their site. It does show the actual scanning bring preformed by displaying the actual rolling frequencies. It can help you tweak the squelch setting to where it is closed , and see the scan speed ect. by seeing what is going on.
Bob
 

crazyretrotech

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Messages
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The Uniden SDS-100 works best in a large statewide system by far. I had a radioshack pro-668 and then a Whistler 1080 which I do prefer in a rural area for conventional pretty much and did get it to finally work ok in simulcast, but still at times struggles and decode can be bad where the Uniden is usually 98%, if not a 100% decode rate even with RSSI above 90 even and just handle simulcast better overall with the true I/Q detect which sure have been in scanners way before, but manufacturers wanted to cut corners and cost. Plus trunking on DMR is better on the Uniden, yes you have to pay for the royalty taxes on the Uniden. Whistler try to get around it and cut cost by following the TG groups instead of the CC.
 
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