Just did a minor "bake off" between four scanners on CivAir . . .

[KB2GOM]

The candidates: Uniden 436 with Diamond 77 antenna, Uniden SDS200 connected to off-center fed dipole, Icom R6 with 20-inch telescopic whip, Uniden 125 with 20-inch telescopic whip.

The 436 and the SDS200 were scanning the Aviation portion of their internal databases; the R6 and 125 were scanning identical lists of CivAir that I had programmed.

The results: the 436 and SDS200 had far fewer hits than the R6 or 125.

It was a real footrace between the R6 and 125. Sometimes the R6 was picking up stuff that the 125 wasn't hearing, and sometimes it was reversed. There was no clear winner. The inexpensive telescopic antennas, set to 20 inches, worked well on both radios.

If pressed, I would say that the R6 appeared a tiny bit -- and I do mean tiny -- bit more sensitive than the 125, but the 125 is easier to use. I did not have the R15 to compare.

Bottom line: if your primary target is Civilian Air frequencies, and you have the R6, use it and be happy. Ditto the Uniden 125. And I think you might be surprised at how well a simple metallic whip antenna set to 20 inches works on either one.

 

[nd5y]

If you are not using the same antenna in the same location and position then your results could be misleading.

 

[kc2asb]

Interesting test. The Uniden 125 continues to punch above its weight. Lots od different opinions on the VHF performance of the SDS series - some say it's great and while others say it's below average.

My 536HP seems fine on VHF. I would assume the 436 is pretty much the same radio RF wise.

 

[KB2GOM]

If you are not using the same antenna in the same location and position then your results could be misleading.

Well, I agree. I was using the scanners as they are normally configured: ie, scanner and antenna combos. However, since the SDS200 was connected to the off-center fed dipole, I would expect that antenna would have higher performance . . . and yet the SDS200/OCFD combo did not out-perform the R6 or 125 on CivAir.

I would be really surprised if the SDS200 connected to a 20-inch telescoping antenna would outperform the R6 or 125 on civilian air with a similar antenna. Perhaps I will run that test one of these days.

 

[KB2GOM]

Interesting test. The Uniden 125 continues to punch above its weight. Lots od different opinions on the VHF performance of the SDS series - some say it's great and while others say it's below average.

My 536HP seems fine on VHF. I would assume the 436 is pretty much the same radio RF wise.

I am not disappointed with the 436 or the SDS200. I use them every work day to monitor local first responders while running The Commuter Assistance Net (which I have run for 29 years.) Commuter Assistance Net

But on CivAir, it seems the R6 and 125 have a clear advantage. However, as I told nd5y, perhaps I will compare the 436 or SDS200 head to head against the R6 or 125 with the same type antenna set at the same length.

 

[R0am3r]

@KG2OM - Out of interest, what is the configuration of the off-center fed dipole? Is this antenna cut for HF or did you make a short version for VHF? Is the antenna horizontally or vertically polarized? Where is the antenna resonant in the VHF band? Is this antenna mounted indoors or outdoors and what feedline did you use for this configuration? What is the height of the antenna and are there structures nearby? Did you model the antenna to see how it performs in the VHF band? I am sure there are numerous other factors to consider.

I may be in the minority, but I typically don't think of using an off-center fed dipole with my scanners. I look forward to reading about your next test.

 

[KB2GOM]

@KG2OM - Out of interest, what is the configuration of the off-center fed dipole? Is this antenna cut for HF or did you make a short version for VHF? Is the antenna horizontally or vertically polarized? Where is the antenna resonant in the VHF band? Is this antenna mounted indoors or outdoors and what feedline did you use for this configuration? What is the height of the antenna and are there structures nearby? Did you model the antenna to see how it performs in the VHF band? I am sure there are numerous other factors to consider.

I may be in the minority, but I typically don't think of using an off-center fed dipole with my scanners. I look forward to reading about your next test.

I am using this version: Homebrewed Off-Center Fed Dipole - The RadioReference Wiki

It is hung vertically in the corner of my radio shack. The shack is in a room that projects from the side of the house. The antenna in indoors, but hung in one of the outer corners of the room, with the top of the long arm about 8 feet in the air. The feedline is RG8, I think. I did not model the antenna, but built it (the wire version) on the recommendation of Popnokick, and I am well satisfied with the performance.

 

[alcahuete]

All this "bake off" does it compare antennas. There is absolutely no comparison of the scanners at all, being on different antennas. Completely useless test.

 

[Ubbe]

When comparing scanners and/or antennas one can use two antenna switches, their two outputs to two scanners and two antennas and their inputs connected to each other. Then you flip a switch quickly for comparison of antennas and/or scanners. Those switches might be $10-$20 and can even be of the F connector type and 75 ohm, it doesn't matter.

https://www.amazon.co.uk/Amateur-Coaxial-Features-Protection-Aluminum/dp/B0FK2VC8Z3/?th=1

https://www.amazon.co.uk/Glayent-Transceiver-DC-500MHz-Frequency-Handheld/dp/B0FLQ32Z8R/

/Ubbe

 

[buddrousa]

A good 4 channel Multi-Coupler connected to 1 Antenna and to 4 Receivers all setup the same is a FAIR TEST and using Switches as Ubbe stated is a good way to test 2 Antennas as a FAIR TEST.

 

[KB2GOM]

All this "bake off" does it compare antennas. There is absolutely no comparison of the scanners at all, being on different antennas. Completely useless test.

Well, likely you are right. However, the R6 and 125 were compared with both equipped with metal telescoping antennas set to the same length.

So I will be equipping the SDS200 with one of those antennas and compared it head-to-head with the125, and then do the same thing with the 436. Perhaps I will be surprised by the results.

 

[kc2asb]

Well, likely you are right. However, the R6 and 125 were compared with both equipped with metal telescoping antennas set to the same length.

So I will be equipping the SDS200 with one of those antennas and compared it head-to-head with the125, and then do the same thing with the 436. Perhaps I will be surprised by the results.

Looking forward to seeing the results. I also like the recommendations above about the antenna switch/multi-coupler. It would be interesting to see the 125/SDS200 and 125/436 head to head on the OCF dipole.

 

[KB2GOM]

Looking forward to seeing the results. I also like the recommendations above about the antenna switch/multi-coupler. It would be interesting to see the 125/SDS200 and 125/436 head to head on the OCF dipole.

Well, I didn't do the antenna switch/multi-coupler test (because I don't have them). However, I did do a quick-and-dirty test where I mounted a 20-inch telescoping antenna on the back of the SDS200, set it on "Aviation" and it definitely seemed to be capturing more hits than the other day. Running the Uniden 125 at the same time with a 20-inch telescoping antenna, sometimes they picked up different hits at the same time, sometimes identical hits, but the SDS200 was definitely capturing more with the 20-inch telescoping antenna than with the OCFD.

Then I locked the SDS200 on the Albany International Airport ATIS system. With the off-center-fed dipole, it showed one bar on the signal strength meter; with the 20-inch telescoping whip, it showed two bars on the signal strength meter.

Frankly I was surprised, but there you have it.

 

[prcguy]

When comparing scanners and/or antennas one can use two antenna switches, their two outputs to two scanners and two antennas and their inputs connected to each other. Then you flip a switch quickly for comparison of antennas and/or scanners. Those switches might be $10-$20 and can even be of the F connector type and 75 ohm, it doesn't matter.

https://www.amazon.co.uk/Amateur-Coaxial-Features-Protection-Aluminum/dp/B0FK2VC8Z3/?th=1

https://www.amazon.co.uk/Glayent-Transceiver-DC-500MHz-Frequency-Handheld/dp/B0FLQ32Z8R/

/Ubbe

I agree, same antenna on all scanners, same location, same time. And add a Yupiteru MVT7100 to you mix, it should pick up better than any scanners mentioned and most that are not. There is a reason its the favorite of airplane spotters and its AM audio is excellent.

 

[Ubbe]

Even testing an antenna at different times might not give a result that can be used. I have most of my antennas around my chimney at a 2ft to 6ft distance to each other and sometimes there's one antenna that works best for a particular frequency and at other times it's another antenna. The weather situation have an impact and of course if it is a moving object like an airplane or a mobile transmitter.

I can't have a scanning list programmed for just a certain set of frequences that works best for that antenna the scanner are connected to, as it will change even during the day, so I end up with almost the same scanlists in all scanners that makes it take a long time to do one scan cycle. But as I have up to 11 scanners in use, as well as SDR# and dsd-fme running, it will always be one that are in the correct position in its scanlist to catch a transmission. If something interesting are happening I make a hold on the system on each scanner to see which one that are the best suited for monitoring that system.

/Ubbe

 

[KB2GOM]

Even testing an antenna at different times might not give a result that can be used. I have most of my antennas around my chimney at a 2ft to 6ft distance to each other and sometimes there's one antenna that works best for a particular frequency and at other times it's another antenna. The weather situation have an impact and of course if it is a moving object like an airplane or a mobile transmitter.

I can't have a scanning list programmed for just a certain set of frequences that works best for that antenna the scanner are connected to, as it will change even during the day, so I end up with almost the same scanlists in all scanners that makes it take a long time to do one scan cycle. But as I have up to 11 scanners in use, as well as SDR# and dsd-fme running, it will always be one that are in the correct position in its scanlist to catch a transmission. If something interesting are happening I make a hold on the system on each scanner to see which one that are the best suited for monitoring that system.

/Ubbe

These were simultaneous tests.

 

[kc2asb]

Well, I didn't do the antenna switch/multi-coupler test (because I don't have them). However, I did do a quick-and-dirty test where I mounted a 20-inch telescoping antenna on the back of the SDS200, set it on "Aviation" and it definitely seemed to be capturing more hits than the other day. Running the Uniden 125 at the same time with a 20-inch telescoping antenna, sometimes they picked up different hits at the same time, sometimes identical hits, but the SDS200 was definitely capturing more with the 20-inch telescoping antenna than with the OCFD.

Then I locked the SDS200 on the Albany International Airport ATIS system. With the off-center-fed dipole, it showed one bar on the signal strength meter; with the 20-inch telescoping whip, it showed two bars on the signal strength meter.

Frankly I was surprised, but there you have it.

Thank for sharing the updated test results. So the SDS200 holds its own on aviation, which is good info for anyone wanting one as a do-it-all scanner.

 

[buddrousa]

Multiple antennas and receivers setting close to each other no isolation while it may be close its not a fair test. With RF feet can make a big difference. Using a Multicoupler with port isolation and identical jumpers connected to 1 antenna at the same time is the most fair test. We were taught that is electronics school all the way back in the late 1970's. RF levels in the same room vary from spot to spot. I can take a service monitor set it up and move it around a room with a rubber duck antenna and the signal will vary.

 

[IC-R20]

The set apart for the R6 and 125 comes when you hook them up to a VHF base antenna, especially with gain. The R6 doesn't intermod nearly as easily as the 125 does.