Balderdash. Reducing the bit error rate from, say 45% to 5%, will have a tremendous impact on the quality of the decoded audio. Error correction algorithms all have their limitations--there are only so many input errors they can correct before the output has errors as well--which directly affects analog audio quality. And what of situations where one antenna doesn't output enough signal for the demodulator to even attempt to decode, but another antenna outputs a signal that decodes cleanly?
BCD436HP/BCD536HP: Antenna upgrade for 436
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Balderdash. Reducing the bit error rate from, say 45% to 5%, will have a tremendous impact on the quality of the decoded audio. Error correction algorithms all have their limitations--there are only so many input errors they can correct before the output has errors as well--which directly affects analog audio quality. And what of situations where one antenna doesn't output enough signal for the demodulator to even attempt to decode, but another antenna outputs a signal that decodes cleanly?
santafe2016
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These discussions are the reason I do not even ask a question on here. Everybody is an expert and no one wants to back down. Crying out loud its each other opinion, who gives a damn who is TECHNICALLY right??
SOFA_KING
Member
Somehow this evolved from "With digital channels, your signal is either there or not." to this now being all about "audio quality".
You can't have good digital "audio quality" if your signal is low enough to cause so many bit errors that intelligibility falls apart...no matter how much you "pray" for it!
And you most certainly can improve BOTH your "signal being there", and therefore "audio quality", by improving you signal with an antenna designed to have more GAIN on the specific band(s) you are trying to receive.
The bottom line is that even on digital signals, any antenna that gives you more signal over another antenna, gives you GREATER RANGE...on analog and digital.
And would someone please show me a "digital antenna" for any "digital" radio communications device? I'd like see one of these elusive creatures. I'd probably have better odds to see Bigfoot, or his Yeti relative!
Phil
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Increasing the amount of signal presented to the receiver will improve reception and (for digital) decode rate. You can increase the amount of signal by:
1) Ensuring that the orientation of the antenna matches the polarity of the signal (i.e. vertical vs. horizontal).
2) Tuning the antenna to best match the frequency of the transmitted signal.
3) (probably should have listed it first, since it is generally the most important) Increasing the altitude of your antenna.
4) Using a directional antenna oriented toward the signal source.
Digital signals are generally transmitted as C4FM (i.e. a 4-level FM signal), CQPSK (a form of phase shifting), or other analog carrier. The signal itself is always analog, even when the content of the signal is digital. The informational content of a digital signal is not the result of the signal rapidly turning on (1) and off (0).
The only form of "digital" transmission method (i.e. the signal is switching between a 0:no signal and 1:signal state) that readily comes to my mind is Continuous Wave (CW) used for Morse code. In this method the carrier wave (which itself is an analog waveform) is turned on and off to send the signal content. In this case, though, it is more than 0 and 1. I believe there are 5 states, but someone can (and almost surely will) correct me on this:
0=Dit (signal present for a short time)
1=Dah (signal present for a longer time)
2=intra-letter pause (signal not present for a short time in between the dits and dahs that make up a letter)
3=inter-letter pause (signal not present for a somewhat longer time in between letters themselves)
4=inter-word pause (signal not present for an even longer time in between words)
There are types of active antenna systems that can perform better with digital signals in a multipath environment.
1) Ensuring that the orientation of the antenna matches the polarity of the signal (i.e. vertical vs. horizontal).
2) Tuning the antenna to best match the frequency of the transmitted signal.
3) (probably should have listed it first, since it is generally the most important) Increasing the altitude of your antenna.
4) Using a directional antenna oriented toward the signal source.
Digital signals are generally transmitted as C4FM (i.e. a 4-level FM signal), CQPSK (a form of phase shifting), or other analog carrier. The signal itself is always analog, even when the content of the signal is digital. The informational content of a digital signal is not the result of the signal rapidly turning on (1) and off (0).
The only form of "digital" transmission method (i.e. the signal is switching between a 0:no signal and 1:signal state) that readily comes to my mind is Continuous Wave (CW) used for Morse code. In this method the carrier wave (which itself is an analog waveform) is turned on and off to send the signal content. In this case, though, it is more than 0 and 1. I believe there are 5 states, but someone can (and almost surely will) correct me on this:
0=Dit (signal present for a short time)
1=Dah (signal present for a longer time)
2=intra-letter pause (signal not present for a short time in between the dits and dahs that make up a letter)
3=inter-letter pause (signal not present for a somewhat longer time in between letters themselves)
4=inter-word pause (signal not present for an even longer time in between words)
There are types of active antenna systems that can perform better with digital signals in a multipath environment.
Look up antenna diversity on Wikipedia (or just look at your Wi-Fi router).
SOFA_KING
Member
I almost stayed on the sidelines, but actually some people want RELIABLE INFORMATION that is FACTUAL AND BASED ON REAL SCIENCE, and not (dare I say) "fake news".
It's a shame when someone is so wrong that they can't admit being wrong despite well-known proven scientific knowledge. The real losers are the people who really want to know the truth about a subject like this. The question was simple, but the answers were tarnished by "fake science". That's the real problem here.
Phil
902
Member
Ya pulled me in, Paul. Those are MIMO schemes which actually use multipath for increased data throughput. Cellular has a bunch of other tricks to increase capacity, like beam forming. We don't use those in land mobile radio, although some very early 800 MHz AMPS cellular implementations did have dual antennas to compensate for Rayleigh fading. Modern systems tend to be significantly overbuilt (often to the point where the problem isn't fading, it's simulcast overlap and phase distortion).
Land mobile radio - analog or digital - has remained fairly basic in fixed-end design. It's usually a chore to convince the designers of a new system to exercise responsible radiation control and focus their RF into the areas that need it, rather than the highest site, with the highest antenna, and the highest power beaming out to the horizon.
I started to type a few replies to this outside of just answering the OP's question, got to about 5,000 words, then said, "Nope!" The tangential break-out reminds me of living three miles away from the TV transmitter, getting a new "television set" and having to run out and get a Color Television antenna - then replace that with a Digital TV antenna some 40 years later - or more recently, digital speaker wire (or speaker wire optimized for jazz).
When I was at RadioShack in the 80's the joke was that 10,000 cases of LP cleaner had magically transformed into CD cleaner one night...at a cost +.
902
Member
Gotta love marketing people.
SOFA_KING
Member
Hey Paul, since you quoted me, (not to sound like someone else...but) I'm a old school AT&T trained cellular field engineer who worked in NYC and NNJ when combined analog and digital sites were still on the air. I also worked for Sprint PCS and Nextel, and used to troubleshoot the most difficult RF issues in the harshest RF environment one could only imagine if you didn't work in that capacity in that area. I have news for you! Diversity antennas were designed and used in the analog days long before digital (except control channels) was used on them. The benefits of diversity were realized for analog, as much as digital. And yes, I even learned about phased array antennas to selectively steer the gain lobes towards a subscriber unit. In the end, It's all just SIGNAL GAIN, and has nothing to do with digital. In fact, NONE of this crap has anything to do with the the OP's simple question. All the "Wikipedia" mumbo jumbo doesn't really help. I'm not impressed with your level of unimpressive "fake" knowledge. You can't fool those who really know this stuff.
I'm not sure why you directed that at me, but I noticed you repeatedly, and intentionally, go out of your way to single me out and try to contradict me. And I also noticed you hardly ever answer questions I ask you directly. And I'm pretty sure you saw my question about if the HP-1 now skips conventional P25 encryption on the latest release or not. No answers from you, Paul. What's up with that,,,Paul?
Phil
SOFA_KING
Member
Great post! You really know your stuff.
I was typing at the same time and trying to basically say the same, but my temper was up by (once again) being singled out by Paul...who appears to like to prove me wrong if he can. I don't feel it's in good spirit, but more of an attempt to try and humiliate me. Just the way I see it after so many attempts.
Phil
While antenna diversity systems can certainly be used for analog, their benefit is not as great as when they are used to overcome multipath interference/fading/phase shifting, etc that more dramatically affect the ability of a receiver to recover digital symbols from such transmissions. So, it is fair to say that they are not specifically "digital antennas" but in common practice they are used as such. Totally impractical for scanners, however, as they typically require some level of processing to use.
benburke
Member
Since the dawn of the digital age, electronic companies have put the word "digital" on nearly every piece of equipment they manufacture. It's a marketing ploy. How in the world can an antenna be digital? They can't truly be digital! An antenna simply transfers a radio waveform to the device it's attached to and converts it, either to an analog waveform or if the radio waveform is a digital signal, a digital to analog converter takes over.
JamesO
Member
The ones that do not back down are usually the ones that think they really know what they are talking about! There seems to always be one in the crowd.
Funny how many of the old school analog guys never really were able to convert, but they think they did.
For the OP, antennas are almost like opinions. Sometimes you have to pony up the cash and try 3-4 and find which one works best for your specific needed.
The frequency bands that you need to monitor also dictate what antenna will work best for your needs.
Since the bulk of my daily monitoring is the 700-900 MHz range, I have found that the Radio Shack/Remtronic antenna does the job I need. For both "digital" and "analog" systems.
Anyway, I hope everyone figures out what works for their monitoring purposes. I am sure I would have many people tell me my base monitoring set up does not work, but it works for me and I my own signal generators and spectrum analyzer so I have spent a lot of time finding what works for me. I use hundreds of feet of RG-6 and I will bet I can out perform most of what people would recommend that I use. I have a few tricks up my sleeve that I have proven that work over the years!
I'll step into the breach here and toss out a couple of my favorites for the 436:
MH-255 VHF/UHF Mini Rubber Duck Antenna with SMA | Scanner Master
HT-55 118-960 MHz Tin Rubber SMA Antenna | Scanner Master
Neither is optimal for 700-800 MHz, however both do quite well in that band, and both work surprisingly well on VHF given their diminutive size. The small size is what I really like about them, and also that each is quite flexible.
And they work for analog OR digital!!!
.
MH-255 VHF/UHF Mini Rubber Duck Antenna with SMA | Scanner Master
HT-55 118-960 MHz Tin Rubber SMA Antenna | Scanner Master
Neither is optimal for 700-800 MHz, however both do quite well in that band, and both work surprisingly well on VHF given their diminutive size. The small size is what I really like about them, and also that each is quite flexible.
And they work for analog OR digital!!!
.
dcisive
Member
Of the many antenna's I have I have a Comet SMA503 TriBand from the early 90's. Works great across the board and is very small and thin. I sure love the idea of one of those smaller one's like you mentioned as well. Might have to give one of those a try at some point. Don't want to give up much gain however. My main listening is in the 400 and 800mhz ranges.
902
Member
Great post! You really know your stuff.
I was typing at the same time and trying to basically say the same, but my temper was up by (once again) being singled out by Paul...who appears to like to prove me wrong if he can. I don't feel it's in good spirit, but more of an attempt to try and humiliate me. Just the way I see it after so many attempts.
Phil
LOL! Thanks, Phil! Now all I have to do is convince my employer of that.
Don't let your temper get the better of you. I know a bunch of people on here in real life, mostly on the regional forums in the places I've lived, but for the most part, I'm an anonymous stranger and most of the things fall into the "nothing personal" category. We're all here to support the hobby as it relates to our interests. Besides, temper stuff gets the mods torqued and eventually bans otherwise interesting people who have a lot to contribute.
As far as Paul and engaging his customers, it's good for one to be kept on their toes. If it weren't for these kinds of animated discussions, I'd be face-into-keyboard asleep with the modern equivalent e-toiling of shoveling coal into a steam boiler chanting "Rah rah revenue." I like the fact that if I have a question, idea (good or completely jackass), or comment, the manufacturer is (kinda?) eager to listen - or maybe more - that he's kinda one of us. I don't see that much. I learn a lot about the state-of-the-art in scanner technology from him and his competition. That helps me in my day job making the systems we listen to work.
902
Member
After a little pondering...
If anyone has smelled something burning, I've been thinking about "digital antennas" and how they might port to the scanner world. The only nexus I can come up with is that "digital" is typically predicated on bandwidth and the ability to maintain a linear net gain across a wide range of frequencies. This would be the case with cellular, as chip sets can function within a broad variety of frequencies. What might be useful is the implementation of screened fractal patterns to enhance the groundplane in handheld scanners. I haven't opened my 436 up (most of me doesn't want to...), but those might actually exist.
Either way, the hobby has some challenges ahead in this and the upcoming decade. Most of those will be political solutions rather than engineering ones.
If anyone has smelled something burning, I've been thinking about "digital antennas" and how they might port to the scanner world. The only nexus I can come up with is that "digital" is typically predicated on bandwidth and the ability to maintain a linear net gain across a wide range of frequencies. This would be the case with cellular, as chip sets can function within a broad variety of frequencies. What might be useful is the implementation of screened fractal patterns to enhance the groundplane in handheld scanners. I haven't opened my 436 up (most of me doesn't want to...), but those might actually exist.
Either way, the hobby has some challenges ahead in this and the upcoming decade. Most of those will be political solutions rather than engineering ones.
SOFA_KING
Member
That's getting too deep...even for me!
And are we talking about digitally controlled antennas? If so, that would also enhance analog. Beatin' a dead horse again however, innovation will certainly continue to push the laws of physics.
But a sufficient counterpoise is certainly necessary for proper antenna tuning, unless you use a half wave design. Most of my better /\/\ radios were designed to couple the hand held radio to the body for counterpoise. I learned that when I worked there and knew some the engineers in Plantation. That's the kind of stuff that makes a better radio with greater range.
Did you see something inside the 436 that might accomplish that function?
Phil
And are we talking about digitally controlled antennas? If so, that would also enhance analog. Beatin' a dead horse again however, innovation will certainly continue to push the laws of physics.
But a sufficient counterpoise is certainly necessary for proper antenna tuning, unless you use a half wave design. Most of my better /\/\ radios were designed to couple the hand held radio to the body for counterpoise. I learned that when I worked there and knew some the engineers in Plantation. That's the kind of stuff that makes a better radio with greater range.
Did you see something inside the 436 that might accomplish that function?
Phil
902
Member
No, I haven't opened mine up. Don't really want to. You'll find the MIMO scheme antennas in cellular phones and other broadband devices. They don't pay off for scanners. But, using fractal patterns might help with the groundplane - to a point. The economics of a product always needs to be calculated into its production. At some point, a decision has to be made that something is "good enough" for production, even though there might a few tweaks of improvement possible here and there. Usually those go into lessons learned for the next revision. Or at least that's been my experience.That's getting too deep...even for me!
And are we talking about digitally controlled antennas? If so, that would also enhance analog. Beatin' a dead horse again however, innovation will certainly continue to push the laws of physics.
But a sufficient counterpoise is certainly necessary for proper antenna tuning, unless you use a half wave design. Most of my better /\/\ radios were designed to couple the hand held radio to the body for counterpoise. I learned that when I worked there and knew some the engineers in Plantation. That's the kind of stuff that makes a better radio with greater range.
Did you see something inside the 436 that might accomplish that function?
Phil
I worked on a bunch of HT220 and MT500 radios that benefited from hand coupling, especially for low band MT500s. I had one or two low band portables. They weren't necessarily the most efficient, but they were my favorites when those frequencies were heavily used. Now I've got one on 52.525 (6 meter ham). 99.9999% of the time it doesn't hear anything.
Talk about pushing the boundaries of physics - I have an acquaintance who worked on the F-15. He tells me much of the body surface of the aircraft is an antenna for one system or another. THERE is where broadband antennas and fractal patterns really pay off.
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