BCD436HP/BCD536HP: Antenna upgrade for 436

[jonwienke]

You are confusing several things here. Bandwidth is limited by channel width, but each individual channel is one small slice of the band as a whole. And the band limits are the same for digital and analog. Antennas are designed for acceptable performance in one or more bands.

The channel width we are discussing here is generally wider for analog signals, or else identical. Analog channels are either 25 KHz or 12.5 KHz, and digital is either 12.5 KHz or occasionally 6.25KHz. The most common channel width for digital or analog is 12.5 KHz. So your argument makes zero sense from that perspective.

When you're talking about an entire band (say 800 MHz public safety), switching to digital does not increase or decrease the range of frequencies used within the band. Digital may more efficiently utilize a slice of bandwidth to allow two conversations where analog permits only one (e.g. TDMA DMR vs. analog FM, both of which use 12.5 KHz channels), but the upper and lower frequency limits are the same in either case. So again, your argument makes zero sense.

If an antenna has 6dBd gain and 1.1 SWR within a given frequency range, it will do so regardless of whether the signals within that range are modulated with analog voice or digital data of some sort.

 

[benburke]

I'm not confusing anything! You simply don't understand what I'm talking about, and that's ok. I worked in analog and digital communications for nearly forty years. I will apologize for I don't have the ability to teach you.

 

[benburke]

I hope the attached file will be of assistance.

 

[JamesO]

Wow, that all I can say, wow.

We are dealing with narrow band digital signals and there is clearly not a specific antenna for "digital" or "analog".

Maybe if you are dealing with ultra wideband digital signals you may want to have an antenna that has flat gain across the expected frequency band, then you would clearly give up performance in other bands/frequencies.

But for Public Service and Land Mobile communications, it does not matter whether you are dealing with analog or digital modulation schemes. RF gain is RF gain and while digital signals have threshold values where they avalanche and drop out, when trying to receive either an Analog or Digital signal the antenna gain will be important and the antenna gain has no negative impact on the signal regardless of the modulation scheme.

Of all the crazy non-sense I have heard, I would hope most people would ignore some of the "noise" and focus on the antennas suggested. I run the Radio Shack/Remtronics antennas for most of my applications and have been happy with this antenna since they were introduced 10?? years ago or when ever they were first released.

 

[sflmonitor]

I agree that you don't need a "digital" antenna for better reception of digital signals. While I may not have the advanced technical knowledge of others, I have some experience with big M LMR equipment and they do not have separate analog and digital antennas for their portables or mobiles. The same antenna is provided for either modulation. Actually, I have not seen any digital antennas on their catalog.

 

[marksmith]

I agree that you don't need a "digital" antenna for better reception of digital signals. While I may not have the advanced technical knowledge of others, I have some experience with big M LMR equipment and they do not have separate analog and digital antennas for their portables or mobiles. The same antenna is provided for either modulation. Actually, I have not seen any digital antennas on their catalog.

If you could find anyone advertising a "digital" antenna, which I have actually seen, it's basically a sales ploy. It's not any different.

Mark
536/436/WS1095/HP1/HP2/996T/996XT/996P2/396XT/325P2/PSR800/15X/others

 

[jonwienke]

I'm not confusing anything! You simply don't understand what I'm talking about, and that's ok. I worked in analog and digital communications for nearly forty years. I will apologize for I don't have the ability to teach you.

I understand all of the modulation techniques mentioned in your PDF. What was totally absent in that document was any reference to the antenna design needing to be different somehow depending on the modulation method(s) are used. You pretty much disproved your own argument.

 

[KR3LC]

If you're a radio engineer, you are remarkably ignorant of basic RF principles. The only things that matter to antenna design are the desired frequency range and the propagation pattern. The modulation type has no relevance whatsoever to the antenna design. 700MHz is 700MHz, regardless of whether the carrier is modulated with an analog FM signal or a digital signal.

There is no such thing as a "digital" antenna.

Exactly correct! Frustrating to see the advertisements for digital TV antennas and to see this misunderstanding extend to this technical hobby.

 

[benburke]

I understand all of the modulation techniques mentioned in your PDF. What was totally absent in that document was any reference to the antenna design needing to be different somehow depending on the modulation method(s) are used. You pretty much disproved your own argument.

I suggest you search the document again. If you don't find a link that will help you, neither can I help you. You pretty much proved what I suspected from the beginning.

 

[jonwienke]

If you're referring to the link on page 2 to the article about antenna designs in cell phones and other wireless devices, it discusses the challenges of fitting 5-7 antennas into a handheld device while achieving acceptable performance, and keeping the antennas from interfering with each other. Nowhere does the article state that digital modulation requires a different antenna design than analog modulation, given the same RF frequency range and channel width.

Nice non sequitur, though.

Today’s Antennas Tune Into The Needs Of Modern Wireless Devices

 

[benburke]

If you're referring to the link on page 2 to the article about antenna designs in cell phones and other wireless devices, it discusses the challenges of fitting 5-7 antennas into a handheld device while achieving acceptable performance, and keeping the antennas from interfering with each other. Nowhere does the article state that digital modulation requires a different antenna design than analog modulation, given the same RF frequency range and channel width.

Nice non sequitur, though.

Today’s Antennas Tune Into The Needs Of Modern Wireless Devices

Everything I have posted, everything I have written, everything I have attempted has been valid. I wish you the best. I pray for you to have a good day.

 

[902]

The frequency band of what you intend to cover matters the most

I have a BCD436HP, I live in what's primarily an 800 MHz area, and I am more than likely to buy a Laird EXC806SM antenna for my radio the next time I make an order from a two-way radio supplier. The stock antenna worked okay on several cross-country trips, but I want something more low profile for local use. It should work fine. It should also work fine when I'm in a primarily UHF area. This doesn't mean I'm tossing the stock antenna, but putting it away for when I want that kind of multiband-optimized performance.

 

[jonwienke]

The PDF and the linked articles are valid; they just don't support your premise that optimal antenna design varies depending on how an RF signal is modulated.

How about you be a dear and cite a specific example from either the PDF or the linked article that mentions a difference in antenna design based solely on modulation method, as opposed to a difference in channel width or operating frequency range?

Or perhaps you could explain how an antenna should be optimized differently for a 7K60FXE DMR/MotoTRBO transmission vs. a 11K2F3E analog FM transmission (both of which must fit within a 12.5 KHz channel) at 460 MHz? What aspects of the antenna design should be altered to optimally receive the digital signal compared to the analog signal?

 

[benburke]

The PDF and the linked articles are valid; they just don't support your premise that optimal antenna design varies depending on how an RF signal is modulated.

How about you be a dear and cite a specific example from either the PDF or the linked article that mentions a difference in antenna design based solely on modulation method, as opposed to a difference in channel width or operating frequency range?

Or perhaps you could explain how an antenna should be optimized differently for a 7K60FXE DMR/MotoTRBO transmission vs. a 11K2F3E analog FM transmission (both of which must fit within a 12.5 KHz channel) at 460 MHz? What aspects of the antenna design should be altered to optimally receive the digital signal compared to the analog signal?

Jon, I'm going to try one more time to see if you are able to understand what I'm trying to convey. I apologize to everyone for I noticed that this particular forum is not intended for technical discussions. "For general chit-chat and non-technical discussion specific to Uniden and does not fall within the above forum topics. This is not the forum to get technical advice from."

I believe (hope) you are knowledgeable enough to understand the difference in amplitude, frequency, and digital modulation. If after this post, you still are not able to understand, do not reply to me again, for you are beginning to antagonize and harass me. I understand that this may be the type person you are, and I will pray for you.

A better antenna will improve the audio quality of an analog signal. With a better antenna, the listener should be able to discern an improvement in the audio quality of an analog signal. A digital signal, as you know, is simply a series of zeroes and ones. Once the signal has been converted from digital to analog, it is what it is.

As I previously stated, error correction and error concealment technology will help insure that the integrity of the bit stream is as accurate as it was when transmitted, but if not, the antenna cannot improve the "audio quality" of the original signal. If the signal is present, it is what it is. And the digital to analog converter will play it back, just as it is. The (please read this carefully) "audio quality" cannot be improved by a better antenna.

If you don't understand, I can't help you to understand. There is ignorance, there is stupidity, and there is evilness. You fit into one of these, but I can't and won't judge you. I'll pray for you and hope God will help you.

 

[jonwienke]

s I previously stated, error correction and error concealment technology will help insure that the integrity of the bit stream is as accurate as it was when transmitted, but if not, the antenna cannot improve the "audio quality" of the original signal. If the signal is present, it is what it is. And the digital to analog converter will play it back, just as it is. The (please read this carefully) "audio quality" cannot be improved by a better antenna.

I do understand. You're simply wrong. In a marginal reception situation, a better antenna WILL decrease the bit error rate by presenting the demodulator/decoder with a less noisy signal which can be decoded with fewer errors. Granted, if the signal is strong enough that the bit error rate is zero, a better antenna cannot reduce the bit error rate to less than zero, but if you have a non-zero bit error rate, or have insufficient signal to decode at all, a better antenna will lower the bit error rate and/or improve signal sufficiently to allow decoding.

In layman's terms, a better antenna will allow reception in situations where reception is not possible at all when using an inferior antenna, and will reduce or eliminate decode errors (garbles and dropouts) in fringe reception areas.

 

[benburke]

I do understand. You're simply wrong. In a marginal reception situation, a better antenna WILL decrease the bit error rate by presenting the demodulator/decoder with a less noisy signal which can be decoded with fewer errors. Granted, if the signal is strong enough that the bit error rate is zero, a better antenna cannot reduce the bit error rate to less than zero, but if you have a non-zero bit error rate, or have insufficient signal to decode at all, a better antenna will lower the bit error rate and/or improve signal sufficiently to allow decoding.

In layman's terms, a better antenna will allow reception in situations where reception is not possible at all when using an inferior antenna, and will reduce or eliminate decode errors (garbles and dropouts) in fringe reception areas.

And I say you're wrong.

 

[byndhlptom]

Digital antenna

I guess I'm with Jon on this.....

Antennas radiate/receive RF, modulation does not effect operation as long as the signal is in the antennas' bandwidth.

Different modulation types can improve the apparent SNR, but the base RF is the same....


$.02

 

[benburke]

0's and 1's. You can improve the bit error rate, but you can't improve the analog audio quality. Scanner antennas were designed for analog signals. Digital technology has improved over the last thirty years, but there is still a limit.

 

[jrl44430]

Exactly correct! Frustrating to see the advertisements for digital TV antennas and to see this misunderstanding extend to this technical hobby.

Digital TV antennas have the longest reflector cut to channel 8. Analog TV antennas have the longest reflector cut to channel 2. It is easy to spot.

 

[sflmonitor]

Ben, you inferring that these old analog antennas are not optimized for digital reception right? So what is the difference between a digital and analog antenna? Specifically in the LMR world of VHF, UHF and 800 MHz. Would you be kind enough to explain to us the difference in design and build between the two? While most of our frequencies at work are p25 digital, we do have some analog stuff. I use 1/2 wave vhf whips in a lot of my installs. Have done so for years, even when p25 did not exist. I haven't seen a difference in design over the years.