Uniden and Whistler Scanner selectivity shootout ..

[SCPD]

The purpose of this thread is to allow some understanding as to why our scanners work (or don't work) as we would like. It is not going to be an exercise in RF design .. it is going to be a bit more simple so that everyone has an opportunity to somewhat understand what it being said.

Me .. I am a ham with my advanced license for over 25 years here in Canada. Equivalent to the Extra class license in the US.

This is about selectivity. Selectivity for the beginner is really the ability for the radio to receive the desired signal while rejecting other signals.

I have found that selectivity is the bastard child that no one ever thinks about.

It seems the conversation here at RR is about how sensitive my scanner is .. well sorry, you can have the most sensitive radio in the world, but if you cannot receive the signal that you want and only that signal, then that sensitivity is well kinda useless. It is all about a balance of both.

And in a scanner that is a very very hard thing to accomplish. Do not fault the manufacturers .. if the radios were closer to perfect, you would not be able to afford to buy one. It is all about economics and how much performance you get for your dollars. There are always compromises to be made when it comes to our scanners.

So a bit about the method that was used to do the testing. We used 3 signal generators .. one for the desired signal and 2 for the "interfering signals".

The scanners were all testing in the exact same fashion .. no changes were made, to make the testing completely impartial. In my mind it is all about finding out the truth about our scanners.

The interfering signals were 98 MHz and 125 MHz. The levels of the interfering signals were constant through all the testing. Signal 1 / 98 MHz was -26 dBm and Signal 2 / 125 MHz was -25 dBm.

In real life terms .. the higher the physical number ie -115 dBm, the less the impact of the interference and the stronger the desired signal will be. The lower the number .. -80 dBm the worse the performance.

Sometimes .. the signal will be lost entirely, something I have seen in my testing in the last week.

The scanners were all tuned to 155.1000 MHz and 868.4000 MHz during the tests.

We tested 5 scanners .. Whistler WS-1095, Whistler WS-1080, Uniden HomePatrol 1, Uniden HomePatrol 2 and Uniden BCD436HP. We thought that this would be typical of what scanners are in use today. Sorry .. we did not have a BCD536HP available to us for testing.

It should be noted that .. the "No interference present" numbers are not true sensitivity figures of the scanners due to the setup used while testing.
If you want true sensitivity results, check the thread at the end of this post.

So .. on with the results. (Note: All S Unit loss numbers are approximate).

Scanner Number 1 / Whistler WS-1095

Frequency 1 - 868.4000 MHz

No interference present -112 dBm
98 MHz interference present - 107 dBm ( loss of -5 dBm / 1 s unit)
98 and 125 MHz interference present - 101 dBm ( loss of -11 dBm / 2 s units)

Frequency 2 - 155.1000 MHz

No interference present -117 dBm
98 MHz interference present - 98 dBm ( loss of -19 dBm / 4 s units)
98 and 125 MHz interference present - 86 dBm ( loss of -31 dBm / 6 s units)


Scanner Number 2 / Whistler WS-1080

Frequency 1 - 868.4000 MHz

No interference present -111 dBm
98 MHz interference present - 93 dBm ( loss of -18 dBm / 3 s units)
98 and 125 MHz interference present - 93 dBm ( loss of -18 dBm / 3 s units)

Frequency 2 - 155.1000 MHz

No interference present -112 dBm
98 MHz interference present - 89 dBm ( loss of -23 dBm / 4 s units)
98 and 125 MHz interference present - 64 dBm ( loss of -48 dBm / 9 s units)


Scanner Number 3 / Uniden BCD436HP

Frequency 1 - 868.4000 MHz

No interference present -114 dBm
98 MHz interference present - 104 dBm ( loss of -10 dBm / 2 s units)
98 and 125 MHz interference present - 104 dBm ( loss of -10 dBm / 2 s units)

Frequency 2 - 155.1000 MHz

No interference present -118 dBm
98 MHz interference present - 114 dBm ( loss of -4 dBm / < 1 s unit)
98 and 125 MHz interference present - 88 dBm ( loss of -30 dBm / 5 s units)


Scanner Number 4 / Uniden HomePatrol 1

Frequency 1 - 868.4000 MHz

No interference present -117 dBm
98 MHz interference present - 101 dBm ( loss of -16 dBm / 3 s unit)
98 and 125 MHz interference present - 101 dBm ( loss of -16 dBm / 3 s units)

Frequency 2 - 155.1000 MHz

No interference present -118 dBm
98 MHz interference present - 115 dBm ( loss of -3 dBm / < 1 s unit)
98 and 125 MHz interference present - 100 dBm ( loss of -18 dBm / 3 s units)


Scanner Number 5 / Uniden HomePatrol 2

Frequency 1 - 868.4000 MHz

No interference present -118 dBm
98 MHz interference present - 100 dBm ( loss of -18 dBm / 3 s units)
98 and 125 MHz interference present - 100 dBm ( loss of -18 dBm / 3 s units)

Frequency 2 - 155.1000 MHz

No interference present -119 dBm
98 MHz interference present - 117 dBm ( loss of -2 dBm / < 1 s unit)
98 and 125 MHz interference present - 103 dBm ( loss of -16 dBm / 3 s units)

Conclusion .. this is really what all you wanted to know right ?

The higher the LOSS figure, (-2 dBm being better than -30 dBm) the weaker the desired signal will be at the frequency tested. So .. a 1 s unit loss may mean that the signal may still be there, but a 9 s unit loss, the signal is not likely to be present.

After looking at the results .. and my real world testing over the last week or so, I would rank the scanners as such (when it comes to their selectivity performance).

1. Uniden HomePatrol 2 * Typical loss -2 to -18 dBm / max 3 s units
Uniden HomePatrol 1 * Typical loss -3 to - 18 dBm / max 3 s units

2. Uniden BCD436HP * Typical loss -4 to -30 dBm / max 5 s units
Whistler WS-1095 * Typical loss -5 to -31 dBm / max 5 s units

3 Whistler WS-1080 * typical loss -18 to - 48 dBm / max 9 s units


To give you a real world outcome as to what this all means, a simple test that everyone should understand.

Two of my scanners the WS-1095 and HomePatrol 1 were tested (yesterday actually) .. using a distant weather channel 162.475 MHz on a Larsen 2/70 antenna. Yes .. your typical ham antenna.

Frequency was tuned in the WS-1095 and NO discernible signal was present. Added a 88-108 MHz FM trap filter .. and the signal magically appears, fixing the problems present in the front end design.

The HomePatrol 1 .. no problems whatsoever receiving the signal.

This is shown in the better performance figures we experienced on the test bench.

This test proved to me something that was very evident to me in the last week .. I had noticed that my HomePatrol was receiving signals that simply were not there on the Whistler scanners. That was on the same Larsen 2/70 antenna.

Thru spectrum sweeps .. it was determined the issue was indeed the very strong FM stations 88-108 MHz in the area.

And .. there are not even any nearby.

They are actually quite a ways away, but they are still having a huge impact on the scanner performance. Lets face it .. wherever you live, they are there and making your scanner perform not as well as it probably should.

So even though in some cases the offending interfering signals were over 700 MHz away .. the receivers were still being desensed, thus they appeared to be very quiet, or almost deaf as some have said. I don't like that term .. as it sounds so negative.

When you are not receiving a signal .. the thing to understand, your scanner may simply be overwhelmed due to these strong signals nearby. Sometimes you just need to give it a little help.

I have noticed often I see people adding larger antennas, which often will make the problem worse and not better.

I should note .. I am not associated with any of the scanner manufacturers, FM trap filter manufacturers etc .. just a hobbyist like most of you just wanting to listen to my radios.

If you should be looking for a FM trap filter, 2 popular models are listed below.

Stridsberg FLT201A Receive Filters, FM Notch and High Pass models

Optoelectronics N100 Optoelectronics, Inc.

Just to not cause a fight ... and I know that to some sensitivity is king, here are some sensitivity numbers of how several scanners actually performed when connected to the test equipment.

I have seen often here on these forums that we want our scanners to be more sensitive .. but that is often not a good thing, as the selectivity tests above prove. If you cannot receive the signal you want .. sensitivity will not do it for you. Selectivity is just as important if not more so.

This test was done some time ago ... using the scanners we had available to us at the time.

http://forums.radioreference.com/gre-scanners/309168-whistler-1080-psr800-psr500-bcd436hp-shootout.html


Happy Scanning
edmscan

 

[jpjohn]

Thank you edmscan for this thorough and plain language explanation. I've learned a lot!!!!!!

 

[pro92b]

Part of the reason for the results you measured is in the front end filtering. GRE cheaped out and used one filter to cover 108-174 MHz while Uniden used two filters in this range, 108-136 and 136-174. That's why GRE/Whistler scanners benefit so much from an FM broadcast filter when trying to receive VHF-HI signals. I think the performance in the first mixer where intermod often occurs is fairly comparable between Uniden and GRE designs with a slight edge going to Uniden. Both brands perform poorly in this area.

 

[SCPD]

Part of the reason for the results you measured is in the front end filtering. GRE cheaped out and used one filter to cover 108-174 MHz while Uniden used two filters in this range, 108-136 and 136-174. That's why GRE/Whistler scanners benefit so much from an FM broadcast filter when trying to receive VHF-HI signals. I think the performance in the first mixer where intermod often occurs is fairly comparable between Uniden and GRE designs with a slight edge going to Uniden. Both brands perform poorly in this area.

My testing co-partner indicated that on his WS1095 / WS-1080 and PSR500 .. even 800 MHz signals were virtually being eliminated until the 88-108 MHz FM trap filter was added.

That is why I take it very easy on the antenna I put on all these scanners.

But the Uniden HomePatrol 1/2 are true champs (they tested virtually identical in all our testing). They were the best scanners we tested and in my mind .. a very under rated scanner. It seems to handle quite well anything we threw at it.

 

[marksmith]

Well done. I have considered the HP2 my favorite radio of the bunch, and got a second one because of that. Now I have more scientific reason why.

Mark
WS1095/536/436/996P2/HP1e/HP2e/996XT/325P2/396XT/PRO668/PSR800/PRO652

 

[pro92b]

GRE radios older than the PSR500 generation were less sensitive on 800 MHz. Whatever they did to crank up the 800 MHz sensitivity reduced the resistance to overload. It is a bit surprising that FM broadcast signals seriously degrade 800 MHz reception. The front end filter for 800 MHz really should do a good job of killing FM broadcast signals if the printed circuit board layout is done right.

 

[SCPD]

GRE radios older than the PSR500 generation were less sensitive on 800 MHz. Whatever they did to crank up the 800 MHz sensitivity reduced the resistance to overload. It is a bit surprising that FM broadcast signals seriously degrade 800 MHz reception. The front end filter for 800 MHz really should do a good job of killing FM broadcast signals if the printed circuit board layout is done right.

I don't think there is any escaping it .. it is just that some of the radios do better at dealing with it than others. But ... they all do have some issues due to the fact that ALL these scanners are such wide band radios.

It is just the nature of the beast and why they probably are not getting better .. cause we are demanding more and more frequency coverage in them.

That is exactly why commercial radios do so well .. cause they do not need to cover anything but a much smaller range of frequencies. And .. the fact that they can be well over 10x the cost, the manufacturers can build them better.

Lets be honest .. if scanners were $1000 no one would buy them. Bad enough my 1095 cost me over $800 up here in Canada. The good thing, I only need one.

 

[Boatanchor]

Part of the reason for the results you measured is in the front end filtering. GRE cheaped out and used one filter to cover 108-174 MHz while Uniden used two filters in this range, 108-136 and 136-174. That's why GRE/Whistler scanners benefit so much from an FM broadcast filter when trying to receive VHF-HI signals. I think the performance in the first mixer where intermod often occurs is fairly comparable between Uniden and GRE designs with a slight edge going to Uniden. Both brands perform poorly in this area.

Nice to see some 'real' receiver testing starting to occur here.

I've known for sometime, through my own testing and observations, that the GRE/RS/Whistler scanners were somewhat handicapped by inadequate front end bandpass filtering and that both manufacturers suffer from poor IP3 performance of the front end amplifiers and mixers in strong signal environments.

The inherently poor IP3 issue is primarily a symptom of two common scanner characteristics.
Firstly, the very broad nature of the front end filtering characteristics, which allows multiple strong signals to be applied to the 'active' amplifier/mixer stages and also the use of very low power (& very poor IP3 performance) devices in the active stages.

It is possible nowadays to use low cost, very low noise and very high IP3 performance active components in amplifiers and mixers. The trouble is, those components tend to be relatively power hungry and can draw upwards of 50mA per device. Obviously, such components cannot be used in a portable, battery powered device.

The main problem I see with both Uniden and Whistler, is that exactly the same RF designs are used in the handheld and the base/mobile scanners. If a manufacturer spent a little more R&D and recognized that most mobile/base scanners will be hooked up to external antennas, maybe then we would see a real 'flagship' base/mobile scanner, with decent IP3, selectivity and sensitivity figures.

After all, it doesn't really matter if a mobile/base scanner's front end circuitry draws an extra 100mA or so.

Until that happens though, expect more of the same but with extra bells and whistles to attract the punters.

 

[Boatanchor]

I will say though that as consumers become more aware of these issues, manufacturers will be forced to address them, if they want to keep selling product.

Fact is, generally speaking scanner RF design hasn't kept up with changes in the industry or the environments that they are supposed to work in. Bands are becoming much more congested, signal strengths are becoming ridiculously high (so that systems can better penetrate buildings) and channel spacing's are becoming narrower. You cannot keep throwing money at the bells and whistles and ignore the most important aspects of any receiver (everything prior to the demodulator stage).

The fact that Uniden released the HP2 in 2014 without even addressing the lack of a NFM filter is testimony to this still occurring..

 

[SCPD]

It really would be very nice to truly have a base unit scanner that is really well designed. :roll::roll: The only problem .. I don't think that there is enough of a market for that to be commercially viable.

The number of people that would likely pay for such a product is probably pretty small.

I think the next 5 years will be interesting in the scanner market.

 

[Boatanchor]

It really would be very nice to truly have a base unit scanner that is really well designed. :roll::roll: The only problem .. I don't think that there is enough of a market for that to be commercially viable.

The number of people that would likely pay for such a product is probably pretty small.

I think the next 5 years will be interesting in the scanner market.

I'm not so sure about the lack of a market for a decent base/mobile scanner.

The feeling I get is that there may well be a pent up demand from existing scanner owners who want to upgrade, but the money is staying in their pockets because they know full well that there simply isn't anything to upgrade to.

Uniden's 'flagship' models, as it turns out, are simply more of the same, but with an extra dollop of bling.

Voyager or some other fanboy will now come on here and say that for Uniden or Whistler to design a scanner with more robust RF stages, the unit would retail at $1000 and nobody would buy it.

I dispute this.

When you think about all the money that Uniden is currently wasting on a silly wifi dongle together with IOS and Android apps, that few will ever use, any argument that spending another $50-100 per unit on the RF stages cannot be justified, is plainly just ludicrous.

Uniden and Whistler have two choices from here on in. Either get with the times and build scanners to suit today's complex RF environments (not gear suitable for the 80's & 90's), or get out of the game completely.

 

[Voyager]

Voyager or some other fanboy will now come on here and say that for Uniden or Whistler to design a scanner with more robust RF stages, the unit would retail at $1000 and nobody would buy it.

I dispute this.

When you think about all the money that Uniden is currently wasting on a silly wifi dongle together with IOS and Android apps, that few will ever use, any argument that spending another $50-100 per unit on the RF stages cannot be justified, is plainly just ludicrous.

Well, AOR should be cleaning up, then.

Also, I think it's very clear that many people want the WiFi features based on all the posts wanting to know when this or that will be released.

All that aside, yes, it costs money to improve designs despite what you believe. You can't just throw a different filter in and expect it to work wonders.

---------------------------------

fan·boy
ˈfanboi/
noun

Someone who knows progress is impossible when you are anchored down.

 

[AA6IO]

Edmscan,
I saw your OP earlier yesterday but just got around to posting now. Thank you for the very thorough testing that you did. The results are very interesting and can be quite useful. Best regards.

 

[Boatanchor]

Well, AOR should be cleaning up, then.

Also, I think it's very clear that many people want the WiFi features based on all the posts wanting to know when this or that will be released.

All that aside, yes, it costs money to improve designs despite what you believe. You can't just throw a different filter in and expect it to work wonders.

Lol, AOR cleaning up

AOR seem to excel in making 'niche' products that appeal to... Well I don't actually know who they are supposed appeal to. The DV1 for example certainly doesn't appeal to the Joe's and Mable's of the world and at a 'cheap' $1500 a pop, not even to Government agencies either.

Yes oddly enough, people want the features they were promised and paid for. However, many 536HP owners will never use the wifi feature because even if Uniden do eventually iron out most of the wrinkles, it is still an ill conceived concept IMHO.

Here's an example of why...

Say you want to remote mount your BCD536HP in your car and use your tablet with Siren as a remote head. You mount the BCD536HP in the trunk of your car and tether your tablet/phone/Android device to the scanner via wifi. Sweet, looks sexy doesn't it.. So far so good.

Now, how do you turn the scanner on or off?

You could just hook the scanner up to the accessory line so that only operates when the vehicles ignition is on? - Wrong!

Yes, you can connect the scanner up to the ignition circuit in the car, but as soon as you cut power via the ignition switch, you will likely corrupt the SD card and operating system because the scanner has not been shut down correctly. Uniden in their wisdom forgot to include any function to remotely operate the power up/down function.

So, back to square one..

From what I can see, the BCD536HP wifi feature is good for one thing only. In other words, remote control and access via the internet. Exactly how many would find this feature useful is debatable considering almost every other recent scanner can already be remotely controlled and accessed via USB and a free streaming app, but Uniden appears to be allocating an awful lot of resources and money onto this one feature, for a minority of users, at the cost of support for it's more popular models such as the 436HP.

Good call Uniden - Well done..

Even those that will never use the wifi dongle still want what they paid for because in the end, along with the dimming LCD illumination and failing RTC batteries, it all effects the resale value of their considerable investment.

 

[SCPD]

Myself .. I would much rather see a well performing radio .. than have all the bells and whistles.

Uniden is all about the bells and whistles.

I just bought the HomePatrol extreme update .. the only reason, if I am going for a road trip and far from home, I would like to be able to edit my programming on the fly if needed. Otherwise .. it is pretty useless and much like many of the bells and whistles on their scanners.

I know I sold my 436HP mainly cause the build quality was poor and the user interface and display was much the same. It could have been so much more.

Whistler is very good at fixing any issues that comes up. Uniden .. no so much. I think that has been to Whistlers advantage.

I would like to get a hold of a 536HP to test, but only 1 of my friends have one. I would never buy one as I do not like the Uniden user interface. If I do manage to test it .. I will post an update.

 

[krokus]

It would be interesting to see a test on a batch of the same model, to average out unit by unit variations.

Sent via Tapatalk

 

[SCPD]

It would be interesting to see a test on a batch of the same model, to average out unit by unit variations.

Sent via Tapatalk

I did a test with a friends HomePatrol 1 the other day .. his and mine were virtually identical in performance on the same antenna as far as we could tell.

A difference of a few dBm points is not going to make any difference. If you really have a dud scanner .. you would know it.

 

[pro92b]

I had a batch of five PRO-97's a while ago and tested them all for raw sensitivity. There was virtually no variation in the measured results. For scanners the peak in terms of radio design and performance was 25 years ago with the PRO-2004, PRO-2005 and PRO2006. Uniden never made anything to compare and GRE's more modern scanners are much inferior.

 

[SCPD]

I had a batch of five PRO-97's a while ago and tested them all for raw sensitivity. There was virtually no variation in the measured results. For scanners the peak in terms of radio design and performance was 25 years ago with the PRO-2004, PRO-2005 and PRO2006. Uniden never made anything to compare and GRE's more modern scanners are much inferior.

I have a Pro 2005 and Pro 2006 that I keep around for just that reason. They are pretty rock solid radios.

 

[Fireboat03]

Corporate Greed caused all of these problems. Build as cheap as possible and charge as much as the market will bare and who cares about the consumer. Uniden was the prime example and we are all still recovering from poorly built radios. O well party on