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The Uniden Tavern - 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.

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  #21 (permalink)  
Old 06-13-2018, 9:07 AM
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Originally Posted by jonwienke View Post
But given equally resonant antennas, the longer one will pick up proportionately more signal. If the antenna's electrical length is 3.4" and its physical length is 1", it's picking up about 30% of the signal a full-length antenna would.
I got to thinking last night about the length of the Unication antenna. How do we know the element is only 1" long? That is just the length of the case. The element could be 3.4" or so in a coil which would make it a physical 1/4 wavelength antenna at 812 MHz. Maybe that explains its good performance (in addition to the radio itself being a well designed receiver.) Maybe it is a fractal antenna I'm sure it is nothing exotic though since it is only $14.95 bought on its own. Wish I still had access to an x-ray machine. And my specialty was not antenna engineering during my career. I did learn from the guys and gals in our antenna lab though that antenna engineering has a certain amount of black magic to it. Any antenna engineers here?
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Old 06-13-2018, 9:14 AM
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On the g5's that we have changed out the oem with a specific 800mhz ant, we found that the 800 ant sometimes grabbed some noise from nearby electronics. Otherwise not much of a difference. We decided the oem is the best performer for the simulcast systems here. It is like the antenna high on simulcast.

A coworker who has trouble with other simulcast issues in the metro area, hooks his up to a simple collapsable / adjustable metal antenna mounted outside and gets very good results.
Yes, the whole is greater than the sum of its parts. We can't really just talk about the antenna in isolation. In a well-engineered system (antenna + radio circuitry all tuned together) the results can be stellar.
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Old 06-13-2018, 9:52 AM
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Originally Posted by radio3353 View Post
I got to thinking last night about the length of the Unication antenna. How do we know the element is only 1" long? That is just the length of the case. The element could be 3.4" or so in a coil which would make it a physical 1/4 wavelength antenna at 812 MHz.
No, that is how it is electrically 3.4" (using ~3.4" of wire wrapped into a coil), and therefore resonates at 800MHz insead of Wi-Fi freqs. The physical size is still 1", and as such is going to pick up about 5.3dB less signal than an antenna where the physical and electrical lengths are both 3.4" (i.e. the active element is not wrapped into a coil).

Also, any reduction in sensitivity to nearby noise sources directly correlates to reduced sensitivity to distant weak signal. The 5.3dB signal reduction that applies to nearby RFI applies equally to distant weak signals.
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Old 06-13-2018, 11:14 AM
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https://forums.radioreference.com/un...ml#post2948768

The Unication stubby is more than 5.3dB worse than full-size antennas for the same band, including Unication and Motorola antennas. There is nothing magical about it.
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Old 06-13-2018, 11:43 AM
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Quote:
Originally Posted by radio3353 View Post
Yes, the whole is greater than the sum of its parts. We can't really just talk about the antenna in isolation. In a well-engineered system (antenna + radio circuitry all tuned together) the results can be stellar.
Ding ding ding, we have a winner! This is the real answer. How else can the stellar reception and performance be explained?
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Old 06-13-2018, 1:51 PM
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Some actual data, FWIW: https://forums.radioreference.com/un...omparison.html

Seems to backup Jon's 5.3dB theory (although this is signal strength, not SNR)

From a practical perspective, I've found the G5 with stock antenna to be quite impressive in terms of RF performance, and I really like the form-factor. I have lots of other gripes about the G5, though, and it is a band-specific radio...
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Old 06-13-2018, 2:16 PM
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Originally Posted by dseven View Post
Some actual data, FWIW: https://forums.radioreference.com/un...omparison.html

Seems to backup Jon's 5.3dB theory (although this is signal strength, not SNR)

From a practical perspective, I've found the G5 with stock antenna to be quite impressive in terms of RF performance, and I really like the form-factor. I have lots of other gripes about the G5, though, and it is a band-specific radio...
In head to head testing with a Uniden beta tester standing next to me as a witness, less than an hour ago, I demonstrated that the G4 can pull in distant simulcasts (some VERY distant) with that stubby antenna that the SDS100 couldn't lock onto at all. I suspect a Motorola police radio would also pull in distant simulcasts with a stubby antenna.

There's an old radio guy saying that goes something like..."I'll take a cheap radio with a good antenna over a great radio with a lousy antenna". Oddly enough, the opposite can be true with handheld radios. A great handheld with a lousy antenna will outperform a handheld with issues with whatever duck antenna you want to screw on.

Say what you will about the Unication antenna, but their product, stubby antenna and all, works amazingly well, picking up simulcasts from 30+ miles away. Maybe when I see a scanner that can match that performance firsthand, I'll start worrying about antennas.
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Old 06-13-2018, 2:35 PM
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Many can give a darn about the technical details & specs of why the g5 works with nothing swapped out or added. It just works. It works great on both types of simulcast and that means that its antenna is fine for the design.

I guess i am just going to have to go on a mission to find a short antenna to my liking that works good on my simulcast systems with my sds100.
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Old 06-13-2018, 2:43 PM
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kr7cq, the simulcast that you compared is 30 miles away?
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Old 06-13-2018, 2:45 PM
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Quote:
Originally Posted by vocoder View Post
Many can give a darn about the technical details & specs of why the g5 works with nothing swapped out or added. It just works. It works great on both types of simulcast and that means that its antenna is fine for the design.

I guess i am just going to have to go on a mission to find a short antenna to my liking that works good on my simulcast systems with my sds100.
If you want the best, pick up a Motorola full size 700 MHz duck antenna off of fleabay...then you just need the correct adapter setup. Adapter loss would be negligible. Then check the RSSI numbers for a difference. That's the same antenna used on pretty much all newer public safety handhelds now (that are for that band of course), so I think it's safe to say that it works about as good as a duck antenna is going to work. I picked one up for my G4 for like $15. If you truly want something shorter, there is the stubby Motorola antenna designed for lapel microphones...that would be the next step down in my view. Also, I've heard credible rumors that Unication may be offering such a creature for their units at some point in the near future.
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Old 06-13-2018, 2:47 PM
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kr7cq, the simulcast that you compared is 30 miles away?
Yes, more than that actually. Picking up Mesa Arizona Topaz sites (not the secondary sites located closer to me) from my office in North Phoenix...the G4 had three bars, no signal for the SDS100 or the 436 I've tested.
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Old 06-13-2018, 3:25 PM
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Yes, more than that actually. Picking up Mesa Arizona Topaz sites (not the secondary sites located closer to me) from my office in North Phoenix...the G4 had three bars, no signal for the SDS100 or the 436 I've tested.
I would post your findings here:

https://docs.google.com/spreadsheets...it?usp=sharing
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Old 06-13-2018, 5:12 PM
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The late great radio guy was Bill Cheek. Bill published scanner modification handbook's. The saying <citation needed> was something to the effect of "Give me a $10 radio, and a $100.00 antenna, and I'll play radio with the best of them. And I did". Cheek was a brilliant man. RIP.
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Last edited by pdfdems286; 06-13-2018 at 5:31 PM..
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Old 06-14-2018, 12:01 AM
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I use a Comet Miracle Baby and it works..Not so much in my basement or my boat 30 miles away. Outside and upstairs in the kitchen it works fine. Also in my truck around town. But I have a Radio Shack 800 that works better when needed
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