Motorola Mobile As Base Antenna?

[emsflyer84]

Hey all, I love experimenting with different antennas, I have a mount on my roof and right now I’ve got an NMO ground plane kit up there so I can try my different mobile antennas just for fun. Recently I made an interesting observation when I put a Motorola AN000131A02 (commercial mobile multi-band) up on the roof and found it slightly out-preformed a Comet CA-2X4SR I also had up there for some time. Now, differences are minor, slightly more static in analog vhf, some minor broken transmissions in digital…. But it was noticeable.

Maybe I shouldn’t be surprised given the Motorola is really a commercial grade antenna at more then twice the cost, but it’s also unity gain, multi-band and only 22” tall. And it worked terribly on my car because I couldn’t mount it in the center of my roof.

Surprised and pleased with how it works on my house. One puzzle though…. One UHF frequency comes in noticeably worse on the Motorola antenna then others I’ve tried. Even while almost everything else comes in as good or better. Haven’t figured that one out yet…

Pics for reference

 

[a417]

I've done precisely what you have done, many times over. Try and try again until you find what works for you.

 

[Cameron314]

Any wide band antenna like that is going to be a compromise. You found where the is on that one.

 

[mmckenna]

Maybe I shouldn’t be surprised given the Motorola is really a commercial grade antenna at more then twice the cost, but it’s also unity gain, multi-band and only 22” tall. And it worked terribly on my car because I couldn’t mount it in the center of my roof.

Unity gain on VHF. On UHF it's 3/4 wave and probably has a bit of gain, but the radiation pattern is pointed high, which may explain your experience on UHF.

Sometimes lower gain can work better as the radiation pattern is different.

I'd also look closely as the Comet. If it's been up there a while, it may have some weather issues. Like maybe disassemble the antenna and make sure everything is clean and not corroded.

 

[prcguy]

I have that antenna and its close to 1/4 wave performance on VHF but down some on UHF because it appears to run as a 3/4 wave and the radiation pattern is not ideal at the horizon. In some testing I did in my garage using a home made base station adapter a Comet CA-2X4SR works better on both VHF and UHF than the Motorola, which is actually a PCTEL antenna.

 

[emsflyer84]

Unity gain on VHF. On UHF it's 3/4 wave and probably has a bit of gain, but the radiation pattern is pointed high, which may explain your experience on UHF.

Sometimes lower gain can work better as the radiation pattern is different.

I'd also look closely as the Comet. If it's been up there a while, it may have some weather issues. Like maybe disassemble the antenna and make sure everything is clean and not corroded.

Thanks, the comet is actually fairly new, by “some time” I mean like a month. Doesn’t hurt to check it over though as you suggest.

 

[emsflyer84]

I have that antenna and its close to 1/4 wave performance on VHF but down some on UHF because it appears to run as a 3/4 wave and the radiation pattern is not ideal at the horizon. In some testing I did in my garage using a home made base station adapter a Comet CA-2X4SR works better on both VHF and UHF than the Motorola, which is actually a PCTEL antenna.

Thanks for the insight here, this could definitely be the case.

 

[Anderegg]

I found the triband Larsen 150/450/758 works better for 700, 800, and VHF RX, than the thicc base Moto and alternatives, and also looks normal as well. Not sure on UHF performance, nothing UHF around me.

Paul

 

[mmckenna]

I found the triband Larsen 150/450/758 works better for 700, 800, and VHF RX, than the thicc base Moto and alternatives, and also looks normal as well. Not sure on UHF performance, nothing UHF around me.

Paul

I've used my Larsen on a few UHF systems, and it works. But these are low level/lower power analog repeaters, so not a lot of options for real testing.
I keep meaning to take a 1/4 wave UHF with me to test for comparison.

I had the newer Motorola version, the 'all spring, all the time' version. Got it for free from our County shop, they hate them. I had it on my truck for a short time. Worked fine on VHF. Didn't try on UHF. Not impressive on 800. Plus, the damn thing flopped all over the place up there making a ton of noise. Happily removed it and it lives in my office now, and simply referred to as the HPA "Huge Phallic Antenna". or "Are you compensating for something with that antenna?"

 

[emsflyer84]

I've used my Larsen on a few UHF systems, and it works. But these are low level/lower power analog repeaters, so not a lot of options for real testing.
I keep meaning to take a 1/4 wave UHF with me to test for comparison.

I had the newer Motorola version, the 'all spring, all the time' version. Got it for free from our County shop, they hate them. I had it on my truck for a short time. Worked fine on VHF. Didn't try on UHF. Not impressive on 800. Plus, the damn thing flopped all over the place up there making a ton of noise. Happily removed it and it lives in my office now, and simply referred to as the HPA "Huge Phallic Antenna". or "Are you compensating for something with that antenna?"

That’s funny, I don’t think I’ll end up leaving this thing on my roof because it’s been pretty bad on UHF, but honestly I was hearing things I’ve never heard before on VHF with it, even when comparing to my Diamond X50C. Must be just my particular situation combined with the 0 gain radiation pattern on VHF or something….

 

[Deeptow]

Hey all, I love experimenting with different antennas, I have a mount on my roof and right now I’ve got an NMO ground plane kit up there so I can try my different mobile antennas just for fun. Recently I made an interesting observation when I put a Motorola AN000131A02 (commercial mobile multi-band) up on the roof and found it slightly out-preformed a Comet CA-2X4SR I also had up there for some time. Now, differences are minor, slightly more static in analog vhf, some minor broken transmissions in digital…. But it was noticeable.

Maybe I shouldn’t be surprised given the Motorola is really a commercial grade antenna at more then twice the cost, but it’s also unity gain, multi-band and only 22” tall. And it worked terribly on my car because I couldn’t mount it in the center of my roof.

Surprised and pleased with how it works on my house. One puzzle though…. One UHF frequency comes in noticeably worse on the Motorola antenna then others I’ve tried. Even while almost everything else comes in as good or better. Haven’t figured that one out yet…

Pics for reference

My radio club has a number of the Motorola AN type antennas on our comms van. They work fine with the Trunktracker onboard as well as on 2 meters and 440.
Somewhere in RadioReference there is a plan for a homebrew multiband groundplane antenna. I built it and put it in my attic, about 15 ft. above ground level. It's built of scrap wire, brass rod and an SO-239 connector and fed with 20 ft. of RG8X. It feeds two scanners, although both are not on at the same time. This has proven to work well on all bands I listen to, my local FD is lowband, state and local police are 800 mhz and it also works very well on local rail frequencies. Fun to make and works just fine.

 

[prcguy]

My radio club has a number of the Motorola AN type antennas on our comms van. They work fine with the Trunktracker onboard as well as on 2 meters and 440.
Somewhere in RadioReference there is a plan for a homebrew multiband groundplane antenna. I built it and put it in my attic, about 15 ft. above ground level. It's built of scrap wire, brass rod and an SO-239 connector and fed with 20 ft. of RG8X. It feeds two scanners, although both are not on at the same time. This has proven to work well on all bands I listen to, my local FD is lowband, state and local police are 800 mhz and it also works very well on local rail frequencies. Fun to make and works just fine.

You say the Motorola AN series works fine and I believe you, but my question is it works fine compared to what?

 

[emsflyer84]

My radio club has a number of the Motorola AN type antennas on our comms van. They work fine with the Trunktracker onboard as well as on 2 meters and 440.
Somewhere in RadioReference there is a plan for a homebrew multiband groundplane antenna. I built it and put it in my attic, about 15 ft. above ground level. It's built of scrap wire, brass rod and an SO-239 connector and fed with 20 ft. of RG8X. It feeds two scanners, although both are not on at the same time. This has proven to work well on all bands I listen to, my local FD is lowband, state and local police are 800 mhz and it also works very well on local rail frequencies. Fun to make and works just fine.

That's cool. So I just put my Diamond X50 back on the roof and I swear I'm not hearing as much now as I was with the Motorola, haha./ It's fun to play around.

 

[prcguy]

That's cool. So I just put my Diamond X50 back on the roof and I swear I'm not hearing as much now as I was with the Motorola, haha./ It's fun to play around.

The Diamond X50 is an amateur band only antenna and performance falls off outside the amateur bands. If you’re using the X50 above 155 or 460MHz I can see how the Motorola might seem better.

 

[emsflyer84]

The Diamond X50 is an amateur band only antenna and performance falls off outside the amateur bands. If you’re using the X50 above 155 or 460MHz I can see how the Motorola might seem better.

Sorry, should have mentioned its the X50C, tuned to 148-155 and 450-465. Great point though, even that is still at the edge of what I'm scanning...

 

[Deeptow]

I have a Diamond X30-the little brother of the X50-up about 30 ft. on a fiberglas pole. It's a great amateur antenna for "distant" repeaters but I've never used it for scanning other than on RR freqs, where it does well.

 

[Deeptow]

You say the Motorola AN series works fine and I believe you, but my question is it works fine compared to what?

I guess the right way to put it is "it gets the job done".

 

[prcguy]

I guess the right way to put it is "it gets the job done".

Yea, but the Motorola is not cheap, at $75 and up on flea bay. There is a new Maxrad MAXSCAN1000 on eBay now for $25 that will work similar to the Motorola or a Tram for $30 that will also do the job.