BCD436HP first-month performance assessment

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lamarrsy

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Mmmmm.....
I am no expert at this but, I remember a similar problem with the BCD396XT (or was it the BCD396T?) and it was indeed improved via a firmware update.
 

Hulca

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Waiting for the 2nd firmware update for the 436 as promised at the end of March.....................
 

kc5igh

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Hi,
Ok so, we're at least 3 with a similar problem on analog freqs.
Coincidence seem less probable now with 3 than with 2 ;-)

Let's see to what and where this discussion will lead us to.

-Sylvain.

Good morning, Sylvain.

Make that "four" of us with a similar problem . . .

-Johnnie
 

lamarrsy

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Hey,
That's a very good point: does the 436 / 536 would be hardware compatible with DMR/Mototrbo and NXDN decode, now that they do TDMA (P25 ph2) and already do FDMA (P25 ph1) ?? ---if we put aside the licensing topic--- ?

Sylvain.
 

SCPD

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I second this!

derevs, Maybe you should have read what I wrote before you answered. My point was that the older scanners are clearly picking up signals and the 436 is not. Wellington County Fire is broadcast on the Fleetnet system and can be picked up over a huge area. Niagara County Sherriff's signal comes straight across the lake. Peel's fire dispatch is broadcast from Bramalea for Mississauga Fire and the 436 struggles to pick it up. I also listen to Pearson Airport and the tower and ground frequencies suffer from the same problem. There are clearly differences between the older scanners and the 436.

I second this! The older x96XT's picked up better,when I had the 536HP,aircraft reception was fuzzy and almost unintelligible.Missing cals and warbly muddy sound is what the new radios give you.
 

kc5igh

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BCD436HP good news?

I've previously posted comments about the problems I'm having monitoring a local P25 system on the 436 that my other radios receive promptly and clearly. In fact, it was dropping 40% to 50% of the traffic on that five-channel trunked system.

I've got my fingers crossed, but after extensive testing/tweaking, I've found that moving the threshold mode from auto to manual and resetting the threshold level to 7 (from its auto setting of 8) may be solving the problem.

I don't understand why the default settings on my other radios (BCD396XT, BCD396T, PSR-500, PSR-800) work so well and didn't require changes, but I'm cautiously optimistic that this adjustment will improve the 436's performance for this particular system.

Now . . . back to trying to figure out why the 436 is so deaf to analog signals . . .

Bring on that next firmware update, Paul!

Thanks for listening.

-Johnnie
 

kc5igh

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I spoke too soon . . .

I've previously posted comments about the problems I'm having monitoring a local P25 system on the 436 that my other radios receive promptly and clearly. In fact, it was dropping 40% to 50% of the traffic on that five-channel trunked system.

I've got my fingers crossed, but after extensive testing/tweaking, I've found that moving the threshold mode from auto to manual and resetting the threshold level to 7 (from its auto setting of 8) may be solving the problem.

I don't understand why the default settings on my other radios (BCD396XT, BCD396T, PSR-500, PSR-800) work so well and didn't require changes, but I'm cautiously optimistic that this adjustment will improve the 436's performance for this particular system.

Now . . . back to trying to figure out why the 436 is so deaf to analog signals . . .

Bring on that next firmware update, Paul!

Thanks for listening.

-Johnnie

UPDATE: I spoke too soon. The 436 is again missing sizeable amounts of traffic on the aforementioned five-channel P25 system.

My apologies if I led anyone astray . . .

These threshold mode/level adjustments may nonetheless be perfectly good adjustments for other people having similar problems.

-Johnnie
 

Boatanchor

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Quantify it..

Come on guys, there has to be someone out there with access to a half decent signal generator/service monitor that can post a video comparison of the x36HP with say a x96XT or GRE scanner under weak signal FM & AM conditions.

The significant differences in sensitivity you guys are experiencing on analogue AM & FM would have to be carried over to digital too, since the same RF path is used for both and the only difference is the demodulation stage. And, this difference should be able to be quantified pretty easily in a simple A/B comparisons even if you don't have access to a calibrated signal generator.

If you don't have access to a V/UHF signal generator, just use a known weak/distant off-air signal (preferably using an external antenna to eliminate any in shack/near field variations) and do an A/B comparison of reception by changing the antenna lead from one radio to the other.

Without such documented evidence, it's easy to dispel such variations in reception as they may well be caused by variations in the location and characteristics of the supplied rubber ducky or telescopic antennas or even near field noise sources within the room.

I think that some valid comparisons would interest not only potential owners of the new radios, but also Uniden.
 

lamarrsy

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Hi,

I have already done the "just use a known weak/distant off-air signal (...) and do an A/B comparison of reception by changing the antenna lead from one radio to the other".

With this simple A/B comparison that I have done with a BCD436HP and a BCD396XT, there *IS* a noticeable difference.

As for the impact of this low sensitivity on P25 systems , don't forget that a lower level VHF control signal (on the BCD436HP) doesn't translate into a noisier reception... The digital comms will stay clear until the signal is on the floor... ;-)
 

Boatanchor

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Hi,

As for the impact of this low sensitivity on P25 systems , don't forget that a lower level VHF control signal (on the BCD436HP) doesn't translate into a noisier reception... The digital comms will stay clear until the signal is on the floor... ;-)

What I meant was that many of us like to monitor distant and weak P25 systems too.

I monitor conventional and trunking UHF P25 networks that don't even register on the 'S' meter on the x96xt scanners. I use good, home base (roof) and vehicle mounted antennas. I know that these older scanners can get pretty good P25 decode, down to about -115dBm (and considerably lower when I use a low noise pre-amp).

I'm fully aware of the characteristics of P25, however, if the control channel and voice channels are weak but 'monitorable' on a 996xt or similar scanner, maybe switching over to a x36HP, would make that system 'un-monitorable' - for want of a better term :)

Obviously, raw sensitivity is not going to make much difference for the vast majority of users who run their scanners with poor indoor antennas, in RF noisy environments.

Anyway, hopefully someone will do some 'critical' testing and comparisons on these new models to find out what is really going on.

I will say one thing though. Unless the preamplifier gain level in the front end of these new scanners can be tweaked via firmware, I can't see how a firmware change could alter the analogue sensitivity that some are reporting for a few reasons..

#1 Uniden do not employ high Q, frequency tracking bandpass filters in the front end of these scanners.
(So, there is no likelihood of 'tweaking' the performance of these filters with a firmware change).

#2 Uniden still employ old school AM & FM detector & discriminator circuits for analogue demodulation.
(There is no likelihood of a firmware change effecting the performance of these circuits)

#3 Uniden are unlikely to route the demodulated analogue audio through any kind of DSP (unfortunately).
(So, altering the firmware is unlikely to have any significant impact on the analogue audio characteristics).

As I said though, there may be some form of software controlled gain control in the front end pre-amp. If so, Uniden may have the ability to adjust the preamplifier gain somewhat (but I doubt it).
 

DSC45

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BCD436HP in Somerset County, NJ

I've found that my BCD436HP has outstanding performance on the P25 Phase 1 & 2 in Somerset County. I monitor in the western section of the county in Bridgewater. I'm about two miles from the dispatch center, and pulling in departments as far as 15 miles away. The Phase 2 broadcasts for Hillsbourgh and Bridgewater (when utilizing system) is transmitted and simulcast over P25. Somerset County has been diligent in positioning towers in some low lands. I couldn't be me pleased. My monitoring has incorporated the 536HP & HP-1.
 

kc5igh

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BCD436HP digital performance

I've found that my BCD436HP has outstanding performance on the P25 Phase 1 & 2 in Somerset County. I monitor in the western section of the county in Bridgewater. I'm about two miles from the dispatch center, and pulling in departments as far as 15 miles away. The Phase 2 broadcasts for Hillsbourgh and Bridgewater (when utilizing system) is transmitted and simulcast over P25. Somerset County has been diligent in positioning towers in some low lands. I couldn't be me pleased. My monitoring has incorporated the 536HP & HP-1.

Hello.

I'm glad to hear your 436 is doing well.

My 436 seems to be very, very sensitive to P25 phase 1 signals (there's no phase 2 in this environment, yet).

I was in Colorado a couple of weeks ago, and the 436 monitored the Colorado DTRS beautifully for the entire length of Interstate 25 (Denver, Colorado Springs, Pueblo, etc).

We've got a local trunked system here in northern New Mexico that's gradually transitioning from EDACS to P25 phase 1, and I've had to turn on the radio's attenuator to be able monitor it as well do as my other digital receivers (BCD396T, BCD396XT, PSR-500, and PSR-800). This system appears to be in its early-phase development stage and has yet to be optimized, so I'm hopeful the 436 will behave a little better when that's happened.

I wish my 436 was as sensitive to analog signals in my environment (mountainous, rural) as it is to digital signals, and I'm hoping for a firmware upgrade that will address that possibility.

Thanks for sharing your experiences.

-Johnnie
 

bigrick1964

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I have a Pro-96 I bought several years back and sitting side-by-side with the 436, it picks up signals the 436 can't even begin to hear. I'm using the SMA on the 436 and a RS 800 mhz duck antenna on the 96, very disappointing. On my car I have an outside antenna and sitting in Bryant, AR, my 96 picked up TGID's using the duck that the 436 couldn't hear with the mobile antenna. What gives?
 

FeedForward

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As already mentioned, it is impossible to obtain any valid sensitivity checks without a calibrated communications test set. There are just too many variables. Nobody argues with the fact that two radios can have different apparent sensitivities even used with the same antenna. The reality of electronics is that a box of RF amplifier transistors or RF mixers is going to be all over the place as far as individual characteristics. You have a bell curve of performance, with most coming out in the middle somewhere. Even two radios of the same model and serial run might exhibit noticeable differences in sensitivity. However, the important question would be, "Does the unit meet published sensitivity specs?" Some examples might be better than the specs, some worse. Most will pass, and you hope that the worst ones are pulled before they ship.

In the tube days we all had boxes of RF amplifier, mixer and IF tubes for our receivers. All of those tubes worked, but there was usually one that was quieter and more sensitive than the others. Swapping tubes to get the best performance was common. We don't have that option with solid state stuff, especially surface mount. But, if you suspect that your unit does not meet specifications, have it confirmed and fixed by the factory. That's the way I see it.

FF
 

lamarrsy

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Hi,

I agree with the theoretical approach of not two radios are identical, but apart from production errors radios should perform roughly the same.
What bigrick64 reports here is the same thing I have experienced from two different BCD436HP and have shared here and on other forums & newsgroups: this scanner is the worst performer **on conventional analog VHF** I have seen in 40 years + of scanning and hamming, using near 100 portable radios and scanners thru those years.
No need for fancy thousand dollars test equipment to conclude that a radio is a *real bad* performer when a radio performs as badly as bigrick1964 express here!!!

And this one is. Trust me.

It may shine on the digital side and / or UHF and / or 800, but on conventional analog VHF, it is as deaf as a brick can be.

Too bad. Uniden has lost me with this one. I keep coming back to it for it's others characteristics, but then I miss half of the radio trafic so it keeps going back to the shelf...
 

oem3

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BCD436HP Pros/Cons so far

After reading many posts on the pros/cons, I'm adding my comments.

I agree with many on this scanner.

Pros: Looks nice, a bit thinner than Pro-106, nice display...lots of info, lots of nice features...bells & whistles.

Cons: As others have mentioned, the glare of the plastic display cover. Come on Uniden, this is basic physics, a convex plastic shape reflects at multiple angles. Make it flat at least, also would be slightly less prone to scratches. This is not re-inventing the wheel! Use what is already out there that works.

Sensitivity, again not NEW rocket science, multi-band receivers with good RX sens. have been around for a long time, don't have to re-invent....

Programming is a bear, and not for the faint at heart. Good that it comes with USB and downloadable software. Settings play a big part of how it works, so be careful. The Sentinel does work and you can do a lot, just have to be patient and learn how this thing works.

There are other complaints out there, someone will always find something to complain about, but a couple of these "big" performance issues should not be there with a Pricey scanner, especially when they should not be that hard to change.

I've been in radio, scanners, ham radio, commercial for over 30 years and I'm a licensed electrical engineer, so I don't understand the design team's oversight on some of these issues.

Otherwise I do like the scanner, still learning more about it.
 

ratboy

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I know quite a few people who have just given up on the X36 scanners due to the sensitivity issues and SD card corruption issues. Even the few that have kept them have major complaints. As much as these things cost, they shouldn't have any problems receiving plain old analog FM, but they do. A comparison of a friend's new out of the box 436HP to my old Pro-106 on railband showed a huge difference. Basically, the Uniden was almost totally deaf, only picking up a train less than a mile from where we were sitting (In my car),using a magnetic mount 2 meter antenna. The 106, with the stock duck, was picking up the train about 15 miles away, the dispatcher, several other weaker trains on the NS 161.070 road frequency. Other rail freqs had a lot of traffic on the 106, were not heard at all on the 436. Only one WX freq could be heard, it was coming from less than a mile away, and it was hissy! I could hear 4 of them on the 106. On 800 digital, the 436 was a lot better, but still not as good as my 106. All the toys on this radio are useless without a decently performing radio as the core.
 
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