BCD436HP/BCD536HP: BCD436HP - The Sensitivity "test" (it had to come out eventually..)

[AA6IO]

Just saw Phil's comments in #179. He and I must have been typing at the same time. This is why I like the WiFi access point feature of the 536HP. I can put it somewhere around the house, even outside in the backyard, away from the computer/TV/whatever crud and get better results.
Its amazing the difference with my 536HP with the stock antenna between my home office with computers vs. out in the front room with no computers nearby. I use some ferrite chokes, but probably not enough.

Steve AA6IO

 

[joeuser]

I have chokes on all my radios, on the power cords & the lines in & out - antenna cable, data Cables, audio out, etc. I don't think I'd have enough money to choke every other electronic device in the house though! I mean, we got 5 flat screen TV panels, probably a dozen monitors, last count we had 26 computers tablets, laptops, etc... Good Lord... That's hardcore!

 

[SOFA_KING]

Just saw Phil's comments in #179. He and I must have been typing at the same time. This is why I like the WiFi access point feature of the 536HP. I can put it somewhere around the house, even outside in the backyard, away from the computer/TV/whatever crud and get better results.
Its amazing the difference with my 536HP with the stock antenna between my home office with computers vs. out in the front room with no computers nearby. I use some ferrite chokes, but probably not enough.

Steve AA6IO

Exactly. Ferrite chokes cost money. I have been purchasing a few at a time over many years. Although we have more choices than Rat Shack now with the Internet, so price options today are better. Even then, at some point I have to move them from one device to another when I run out of chokes. Hopefully I get to backfill them when I purchase more.

The possibility of internal noise on the 436 could be proven with a "very sensitive" spectrum analyzer and an appropriate "sniffer" loop antenna. If I still had 24x7 access to such equipment, I would check it out throughly. I do miss having that equipment on hand. My current employer ships me the test gear when there is an urgent need to use it. What a bunch of cheap &@$+@^*$.

P

 

[sibbley]

External noise sources are just that...external. You can't blame the scanner for any of that. Plus, noise emissions can be wide or narrow in bandwidth. So different receivers will react differently depending on how wide the receiver selectivity is and how sensitive the receiver is.

What most people are not aware of is noise that is very wide in nature, but not breaking open the squelch. It is still degrading reception even though you don't "hear" it. To the receiver, it just looks like a high noise floor. You might see some elevated S meter readings, but a lot of noise can be destructive even below "one bar". The only way to actually know for sure what type of noise is out there, and how strong it really is, is checking the spectrum with a very sensitive spectrum analyzer. Then you can actually SEE consumer trash, cable leakage, wide band computer noise, real actual intermod, power line noise...you name it.

For those who suffer noise emissions from their own consumer garbage, there is hope you can diminish or even eliminate the problem. Clamp ferrite chokes on every lead wire or cable that goes into or out of those devices. Put the chokes as close as possible to where it enters those devices. You may be surprised at how you can eliminate the problem. And if you transmit radio signals, like ham or CB, your devices will benefit from reduced interference. Blaming the scanner will not do anything to help.

I clamp ferrite chokes on everything! Especially anything coming in or out of a computer. Even on the power leads. And I try and use GOOD shielded cables on everything...including power leads if they are available. My TV sets and home theater equipment have chokes on all leads. All networking equipment, as well. Guess what? I have zero noise coming out of my devices, and no interference issues when I transmit. I checked my house with a sensitive spectrum analyzer, and I'm totally clean. My neighbors or my cable company? Not so clean, but than it comes down to diplomacy. If they will allow you to install chokes, you can usually fix their stuff too. The cable company? First you have to be 100% able to prove it is them, then present the evidence and wait for them to check the area and fix it. If they don't (which is rare), threaten you will report them to the Cable Commission or FCC for violating cable leakage laws. The power companies also have leakage laws, but are often lax on maintaining acceptable levels. But the point is that YOU CAN do something about most noise and interference issues if you take the initiative.

Phil

Good read, great points. I would say my house must be full of consumer garbage. I'll have to look into ferrite chokes.

 

[stingray327]

Could it be your car? Old fashioned ignition noise, maybe? Fuel pump noise, perhaps?

When I do open searches while traveling around, I'm always amazed by the signals other vehicles emit. Some are so bad that they can be jamming me from many car lengths away. And some can jam many frequencies. Even my own SUV has a couple of birdies I have to temporarily lockout. Then there are gas stations and even residential habitats that emit trash. One I got today on low band sounded just like the old CRT TV sets of the 70's and was picked up for at least three tenths of a mile. It's a wasteland out there in RF land. Trash everywhere. Then there is power line noise, although usually reduced on VHF high band, it can still be a problem at times. But you can't blame the scanner for any of that. The FCC? Yes, you can blame them.

Phil

One thing I do notice and it doesn't interfere with scanner is that I installed brighter LED reverse lights so whenever I put car in reverse it blanks out FM stereo radio.

 

[SOFA_KING]

Good read, great points. I would say my house must be full of consumer garbage. I'll have to look into ferrite chokes.

Thanks. I'm Glad if it helped.

P

 

[bearcat]

436 UHF Sensitivity Poor

I can verify that my 436 is very poor on VHF/UHF. Side by side with the 396xt there is no comparison. The 436 just plain stinks on these bands. Even on full quieting signals I can hear a flutter in the audio. I live at about 1500ft of elevation so there is plenty of RF to hear. I know folks have said that using an outside antenna helps, but I prefer using it portable. Most of the poor reception is on signals that show full scale on the S-Meter on the display. Try this:

Take a 1 ft piece of coax and connect it to the radio put the antenna on the other end. Move the antenna away from the radio. I bet you will see a marked improvement in the signal quality. Now move the antenna towards the SMA on top of the radio you should hear the noise increase dramatically.

Rich

 

[K2RNI]

not uniden bashing, just stating my feelings. uniden imho was so eager to get the 436hp out the door before whistler hit, with the same scanners that gre produced. they just comprimised features over performance. what a huge disappointment !. i promise i will not say anything more. i'll just stick with my older unidens.

Funny just like they tried doing again with the DMR update for it. I've always been a big Uniden fanboy but Whistler is starting to look like a pretty good option lately sad to say. Hopefully they'll make a bcd396P2 finally. (yes I realize there is a 325p2).

 

[k3fs]

The 436 has poor reception on UHF and VHF using a duck antenna mounted on the radio. 700/800 receptions seems to be good.

As Rich mentioned, mount that same duck some distance from the radio and it receives well. The 396XT doe a much better job receiving as a portable. I have found that the 436 will do slightly better than the 396 when connected to the same outside antenna.

 

[kc5igh]

The 436 has poor reception on UHF and VHF using a duck antenna mounted on the radio. 700/800 receptions seems to be good.

As Rich mentioned, mount that same duck some distance from the radio and it receives well. The 396XT doe a much better job receiving as a portable. I have found that the 436 will do slightly better than the 396 when connected to the same outside antenna.

That's also been my experience with the 436 and the 396XT.

The 436 seems to generate rf noise internally (the liquid crystal display?) in the VHF-hi range. Mounting the antenna away from the radio results in immediate improvement.

I bought the 436 because it's a portable scanner, and it's unfortunate that I have to treat it like a mobile/base scanner to bring its VHF-hi performance up to par. I will say, however, that my 436's sensitivity gets better with direct-mount ducks as I move up the rf spectrum. When it reaches 800 Mhz, its sensitivity is comparable to the 396XT.

Oh well . . .

-Johnnie

 

[buddrousa]

Mine works great beside my 668 106 pro 18 and misses less digital than my 106 668 pro 18

 

[Anderegg]

That's also been my experience with the 436 and the 396XT.

The 436 seems to generate rf noise internally (the liquid crystal display?) in the VHF-hi range. Mounting the antenna away from the radio results in immediate improvement.

I bought the 436 because it's a portable scanner, and it's unfortunate that I have to treat it like a mobile/base scanner to bring its VHF-hi performance up to par. I will say, however, that my 436's sensitivity gets better with direct-mount ducks as I move up the rf spectrum. When it reaches 800 Mhz, its sensitivity is comparable to the 396XT.

Oh well . . .

-Johnnie

Are you saying that with the antenna seperated from the 436, it receives as sensative as the 396 in 800MHz? I tested my 436 against my 396 when i first got it, and 800MHz performance was severely lacking on the new model. The 396 would RX analog trunked voice, 436 couldnt even find the control channel.

Paul

 

[adcockfred]

So, is there a better antenna for the 436 running 800 than a fox hunter loop? I did see improvement when running the loop antenna on a hose out the window.

 

[sibbley]

Are you saying that with the antenna seperated from the 436, it receives as sensative as the 396 in 800MHz? I tested my 436 against my 396 when i first got it, and 800MHz performance was severely lacking on the new model. The 396 would RX analog trunked voice, 436 couldnt even find the control channel.

Paul

IMHO, The farther the antenna gets from the scanner, the better it receives across the spectrum. Using a mobile antenna mounted on the roof of the car, my 436 is better than my 396.

I've always found the 436 to have excellent receive on 700/800mhz. VHF/UHF not so good with a duck. Move the antenna away from the scanner and those bands get much better.

 

[adcockfred]

Yeah I have often though about buying a 800 ground plane antenna. running that loop taped to the side view mirror, not smart. The only ground plane antenna I have is V when I bought my first digital scanner 2096 for the state system that went digital a couple of years before 1A7.

 

[kc5igh]

Are you saying that with the antenna seperated from the 436, it receives as sensative as the 396 in 800MHz? I tested my 436 against my 396 when i first got it, and 800MHz performance was severely lacking on the new model. The 396 would RX analog trunked voice, 436 couldnt even find the control channel.

Paul

No, I'm saying that, with the antenna attached to the 436, it's sensitivity in the 800 MHz range is comparable to that of my 396's.

Your experience and that of others is making me wonder what kind of quality-control issues Uniden may have encountered at their assembly plant in Vietnam as the 436 swung into production.

The 396XT seems to have been the quality high-point for many of us.

 

[cmdrwill]

That's also been my experience with the 436 and the 396XT.

The 436 seems to generate rf noise internally (the liquid crystal display?) in the VHF-hi range. Mounting the antenna away from the radio results in immediate improvement.
-Johnnie

Interesting observation. So now we will see a broad band ferrite choke on the antenna cable near the radio.

 

[Haley]

I have said it before, but these are my conclusions also. The 436hp does fine on 700/800 systems, while the 396 (and 346 for that matter) just kills it everywhere else. If my 396 had phase 2 (with, or without DMR, Provoice) it would absolutely be favorite HH scanner , possibly of all time (for me). Mike

 

[kc5igh]

Interesting observation. So now we will see a broad band ferrite choke on the antenna cable near the radio.

Would that help?

I've used filters to minimize signal overload from known external sources such as pagers, but I'm fuzzy on how a broad-band ferrite choke would address internally generated noise . . . if that is indeed what's going on with my 436.

Thanks!

 

[Nasby]

The 436HP was most likely designed to give optimal performance and sensitivity on the popular digital trunking frequencies (800mhz, etc.).

ln this area it excels!

As for VHF-Hi, it plain out sucks. No matter what antenna is attached to it.