Comparison, Larsen Tri-band, Laird WPD136M6C-001, COMPACtenna Scan III - 118 to 922MHz

[russbrill]

I've been saying that for a long time.
11 years of that on top of my wife's Ford Escape. Simple 1/4 wave. Also, costs less than $10.00

That's funny, my wife's vehicle is the 2014 Ford Escape.. I paid a whole $21.00 for hers.. It has good receive on 150 MHz to 160 MHz...

 

[mmckenna]

That's funny, my wife's vehicle is the 2014 Ford Escape.. I paid a whole $21.00 for hers.. It has good receive on 150 MHz to 160 MHz...

A basic quarter wave has a very wide usable bandwidth.

 

[alcahuete]

Yeah, I've had really good luck with a 1/4 wave as well. That's currently what I run for the most part. Just tried the Laird to hopefully free up an NMO mount for another antenna.

My best-performing antenna is either a PCTEL/Maxrad MWU4505S or MUF4505S. I don't know which it is, since it came with a radio I bought and all the markings are removed, but damn is that thing hot on UHF. Not going to work best with all the mountaintop repeaters out here in Socal, since it's either 4.5 or 5dB gain, but man does it perform.

 

[prcguy]

A little more testing today. I loaned a friend my COMPACtenna tri-band hamster model that covers 2m, 220 and 440 and he compared it on 2m and 440 with a 19" 2m 1/4 wave whip and a Larsen NMO 2/70B, which has been a really good performer. The test area is very hilly like parts of San Francisco and the test vehicle with trunk mounted NMO parked non line of site to me and another friend. My antenna was a GP-9 class dual band about 350ft above sea level and the test vehicle was about 100ft above seal level and a mile away behind hills. We chose this area because the test vehicle drives this area often and complains about sever signal fading.

In all cases receive was better in the test vehicle on the COMPACtenna over the Larsen and 19" whip. To me on 440 it was a toss up between the 19" whip and the COMPACtenna at about 90% quieting with a tiny bit of fade with maybe the slightest margin to the COMPACtenna. The Larsen dual band had terrible fading going from about what the other two did to deep fades where the signal pretty much disappeared at times and it was unusable.

On 2m the Larsen dual band was consistent with no fading and best of the three at my location with the other two very slightly less in signal level and stable. Its interesting the test vehicle got better receive level using the COMPACtenna on 2m where I saw a slight drop compared to the Larsen. The other friend at about 2mi away with more obstructions agreed with me on the UHF testing and on 2m they saw little to no difference between the three antennas. The advertising for the COMPACtenna mentions something about working well in non line of sight conditions and I am seeing this first hand.

Nothing today was conclusive that one antenna is better than the others under all conditions but the COMPACtenna again surprised me and the test vehicle owner, who I hear is now shopping for one.

 

[alcahuete]

That's the Scan III I'm guessing?

 

[russbrill]

A little more testing today. I loaned a friend my COMPACtenna tri-band hamster model that covers 2m, 220 and 440 and he compared it on 2m and 440 with a 19" 2m 1/4 wave whip and a Larsen NMO 2/70B, which has been a really good performer. The test area is very hilly like parts of San Francisco and the test vehicle with trunk mounted NMO parked non line of site to me and another friend. My antenna was a GP-9 class dual band about 350ft above sea level and the test vehicle was about 100ft above seal level and a mile away behind hills. We chose this area because the test vehicle drives this area often and complains about sever signal fading.

In all cases receive was better in the test vehicle on the COMPACtenna over the Larsen and 19" whip. To me on 440 it was a toss up between the 19" whip and the COMPACtenna at about 90% quieting with a tiny bit of fade with maybe the slightest margin to the COMPACtenna. The Larsen dual band had terrible fading going from about what the other two did to deep fades where the signal pretty much disappeared at times and it was unusable.

On 2m the Larsen dual band was consistent with no fading and best of the three at my location with the other two very slightly less in signal level and stable. Its interesting the test vehicle got better receive level using the COMPACtenna on 2m where I saw a slight drop compared to the Larsen. The other friend at about 2mi away with more obstructions agreed with me on the UHF testing and on 2m they saw little to no difference between the three antennas. The advertising for the COMPACtenna mentions something about working well in non line of sight conditions and I am seeing this first hand.

Nothing today was conclusive that one antenna is better than the others under all conditions but the COMPACtenna again surprised me and the test vehicle owner, who I hear is now shopping for one.

In hilly terrain the Larsen is at a disadvantage, it is a 5/8 collinear antenna at 440, while the 19 inch whip acts a 3/4 wave antenna at 440 with a higher take off angle.. Motorola has a white paper on mobile antennas that talks about 1/4, 1/2, and 5/8 wave antennas and the pros and cons under certain conditions... The 1/4 wave always had the best overall performance in hilly terrain in the Motorola study..

 

[prcguy]

Tri-band amateur version.

That's the Scan III I'm guessing?

 

[vagrant]

Just a quick follow-up. My testing results were similar using a VNA and just plain listening to the scanner and looking at the signal strength of the meter. My placement location is on the upper corner of the hood passenger side near the pillar. This location/mount is providing enough of a ground plane that the difference between antennas (Larsen / Scan III) is negligible. With a ground plane below the antenna the winner is Larsen, especially considering the cost difference of the two.

With that in mind I swept them both on a mount location reasonably void of a ground plane. The Scan III offered significant improvement over the Larsen in the 136-174, 318-512, and 750-960 MHz spreads where the Scan III is advertised to perform best. If I did not have a ground plane where the antenna is mounted on my vehicle, I would definitely option for the Scan III.

Conclusion: I will continue to use the Larsen at that mount point.

Next test: My amateur antenna is mounted to the rack of an SUV. I'll give it a whirl there and see what the numbers are against my mobile antenna. Perhaps initial testing this weekend when it cools down as it is over 100F the next couple of days.

In places the COMPACtenna outperformed the others it had a pretty bad match in the center of my roof. If I had the time it would be interesting to repeat the test with all antennas at the rear bed rail on my truck. The match on the Larsen and Laird would probably get worse where the COMPACtenna gets better. Not sure how much that affects overall performance.

 

[prcguy]

I received a new COMPACtenna Scan III yesterday and a gracious RR member sold me an older Scan version recently plus I have the tri-band amateur version. Yesterday I was testing the new Scan III on trunk lid of the wifee's car as I went to LAX to pick her and the grandkids up. When I pulled up the wifee looked confused and told the kids its not me because her car doesn't look like that on the back. Then when she got in the car I got a lecture about not F'ing up her car like I do my truck with all the antennas and what the hell was I thinking with that kids toy looking thing on the trunk. Finally things settled down or so I thought. As I was in bed and just about dozed off, here it comes again with "what were you thinking putting that stupid a$$ F****** antenna on my car????

So even though these COMPACtennas are interesting and work better than expected, there are other things to consider when putting one on your or especially your wife's car.

 

[mmckenna]

So even though these COMPACtennas are interesting and work better than expected, there are other things to consider when putting one on your or especially your wife's car.

Yeah, some of these antennas have what an old co-worker described as the "dork factor". Reminds me of a guy I saw at the last hamfest I went to (10 years ago). Had a mag mount discone on his trunk. I'll bet he was not married.

I agree with your wife.

 

[vagrant]

Ha! You even said that thing looks like ...a donkey d**k.. after mine arrived to you in the mail. hahaha - That's the crucible we must endure when testing on different vehicles and in different locations. We hope for the best, but most girlfriends and wives are having none of it. I cannot say I would not have done anything different though for a chance to test in a different geographic location. A trip to the airport tuned into fun, at least for half the trip.

Here's an idea. You can always hide the Scan III using that other AS-1404/PRC-41. Perfect....