Best NMO mount loaded 1/4 lowband antenna...?

007 · Post by **007** » Fri Jul 16, 2004 11:40 pm

Will be needing one soon for upcoming multi-radio (whacker?) re-vamp/install in my POV Impala.

Due to existing infrastructure and minimal TX time, the lowband antenna will be off on the left rear fender.

What are the best performing NMO mount 1/4 loaded antennae?

RidgeRunner · Post by **RidgeRunner** » Sat Jul 17, 2004 7:58 am

I dont know the model number but I have heard it refered to the pool que. Its made by maxrad as far as I know they offer wide bandwidth and excellent performance...although they are beefy, tried putting one on the roof of my dodge and I thought the S.O.B. was going to tear thru, I had to use an antenex c47...I think thats the number. I hear that antenex has a wide band version of this antenna that supposed to be good, dont know though it its a 1/4 wave although I would look into the maxrad...I have heard nothing but good

wa2zdy · Post by **wa2zdy** » Sat Jul 17, 2004 9:43 am

Question: When did a base loaded antenna become a "loaded quarter wave?" I've seen this description appear in catalogs for a while now and I'm just mystified.

If it was a quarter wave, it wouldn't NEED to be base loaded. If it's base loaded, it's because it's shorter than a quarter wave! (The usual 49" whip is a quarter wave around 57 MHz, so on a lower frequency, it needs to be loaded AND is shorter than a quarter wave.)

Has the mathematical definition on "one quarter" changed?

JohnWayne · Post by **JohnWayne** » Sat Jul 17, 2004 10:54 am

I don't know what frequency range you need to cover, but I've sold hundreds of the Maxrad MLB4700; I also have one on my POV. It covers 47-54MHz. I also have other frequency ranges; they just aren't on the website. If you don't need 6M, then I would probably go with an Antenex model; they are higher quality than Maxrad. A model C40 that does 40-47MHz is $35.85. They also have the "wideband" models that cover a wide range with a pretty flat SWR and require no cutting. A model CW42 does 42-48MHz and is $49.50. I use two of the VHF widebands (CWB1443) on my POV and really like them.

I am a big Antenex fan and prefer them over the Maxrad, but the Antenex doesn't make a lowband that covers the 6M ham band for some reason.

Let me know what frequency range you need to cover and I'll narrow down your product options. Just keep in mind that you're not gonna have something that will do 27-54MHz in one antenna. Max bandwidth on them is about 6MHz with a decent SWR.

Jeff

KitN1MCC · Post by **KitN1MCC** » Sat Jul 17, 2004 3:06 pm

comtelco makes an excellent antenna

RidgeRunner · Post by **RidgeRunner** » Sat Jul 17, 2004 6:32 pm

I am using an antenex that I cut down for 6m, but its not what I want. I was thinking about going with the 1/4 whip with spring? What do you think about them as opposed to the mlb4700? I would like to use my existing nmo mount instead of the ball and spring. How would you say the bandwidth of this antenna is that you mentioned johnwayne?

Thanks
Robert

JohnWayne · Post by **JohnWayne** » Sat Jul 17, 2004 6:53 pm

The full-length 1/4 wave whip will outperform the base loaded antennas, but it is basically twice the length. I also don't know of any lowband 1/4 wave whip that goes on an NMO mount. The antenna is just too big, and some serious sheet metal damage could occur. The MLB4700 is going to be basically what you have now: a base loaded whip that is about 48" long.

As the frequency gets lower, the bandwidth of the antenna gets narrower. You're looking at maybe a couple MHz on either side of the center frequency on the upper end of the band towards 50MHz. Expect less than 1MHz in the CB frequency range. When people buy the MLB4700, I usually cut them, at their request, for 52MHz, and the SWR is in the 1.5:1 range on the edges of the band at 50MHz and 54MHz.

I do have the full length 1/4 wave antennas here.

Hope that helps.

Jeff

007 · Post by **007** » Sat Jul 17, 2004 8:02 pm

RidgeRunner wrote:I am using an antenex that I cut down for 6m, but its not what I want. I was thinking about going with the 1/4 whip with spring? What do you think about them as opposed to the mlb4700?

IMHO, and the opinion of most law enforcement agencies still on lowband, the best 1/4w ball mount is the Antenna Specialists ASP
R632. It is an excellent unit, and available with a black ball and flange, so it doens't stick out quite as much on most cars. Some east cost states paint the entire antenna black.

http://www.antenna.com/lm_cat/lmrpg03.html

JohnWayne · Post by **JohnWayne** » Sat Jul 17, 2004 8:26 pm

The ASPR632 is a good antenna, albeit a bit pricey. I do sell the ASPR632 offline for $139 if you do want one.

Thanks,
Jeff

007 · Post by **007** » Sat Jul 17, 2004 9:16 pm

wa2zdy wrote:Question: When did a base loaded antenna become a "loaded quarter wave?" I've seen this description appear in catalogs for a while now and I'm just mystified.

In the case of 6m and 10m mobile NMO mount antennas, the whip is usually in the neighborhood 49" long which is obviously not a 1/4w in length. Therefore, the wire coil in the base has enough wire turns to make the antenna a 1/4w electrically, which results in the antenna being called a base loaded 1/4 wave.

As it's been said, the actual 1/4w length of a 54 MHz or 29 MHz antenna makes a "real" 1/4w whip out of the question for an NMO mount.

On my other car, I've got the AS ballmount I mentioned above, which is cut for 42 MHz, and the lenght of the whip is near 80 inches...that is way too much antenna for an NMO mount!

wa2zdy · Post by **wa2zdy** » Sun Jul 18, 2004 3:41 am

007, you're obviosuly correct and that was my point. If it isn't a quarter wave, it isn't a quarter wave. The base loading makes the radio THINK it's a quarter wave, but it sure doesn't make it act like a quarter wave.

"One quarter" is still one fourth, it's a mathematical term, and the base coil can't change that.

I was just ranting. It's another example of advertising using semantics to make something be something it isn't. But in 30 years of radio, this is just another of many examples.

Thanks.

By the way, the A/S ball mount - does it have teeth to keep the ball from turning on the flange? My Moto does, and thank goodness, for what I put that thing through!

KitN1MCC · Post by **KitN1MCC** » Sun Jul 18, 2004 10:26 am

i have that Antenna specialist one on my truc and i work great on 6m

007 · Post by **007** » Sun Jul 18, 2004 12:47 pm

wa2zdy wrote: By the way, the A/S ball mount - does it have teeth to keep the ball from turning on the flange? My Moto does, and thank goodness, for what I put that thing through!

Affirm. It's not going anywhere.

SlimBob · Post by **SlimBob** » Mon Jul 19, 2004 4:01 am

Larsen makes the NMO50 and the NMO27... They have a few bands in between those... all are NMO, and less than 50" IIRC. But they are coil-equpped antennas... but cheap...

jhooten · Post by **jhooten** » Mon Jul 19, 2004 4:36 am

On top of my truck is a Larsen NMO-Q with a 54 inch .100 replacement rod(they were out of the NMO-50 at the time). It has been run into tree limbs and what not with no damage to the base or the mount. The reflected power on 6m is minimal and I can access the same repreaters I can with the ball mount with the Hustler MO3. In fact it is a little better on some of the marginal machines because of being higher on the roof than the ball back on the rear quarter panel.

RidgeRunner · Post by **RidgeRunner** » Thu Jul 22, 2004 3:56 pm

Just curious? Does this thing hold up good on the roof or does it swing all over the place?

Thanks

jhooten wrote:On top of my truck is a Larsen NMO-Q with a 54 inch .100 replacement rod(they were out of the NMO-50 at the time). It has been run into tree limbs and what not with no damage to the base or the mount. The reflected power on 6m is minimal and I can access the same repreaters I can with the ball mount with the Hustler MO3. In fact it is a little better on some of the marginal machines because of being higher on the roof than the ball back on the rear quarter panel.

KB2ZTX · Post by **KB2ZTX** » Fri Jul 23, 2004 5:03 am

Spectrum !

Nuff said

jas

va3wxm · Post by **va3wxm** » Fri Jul 23, 2004 5:43 am

RidgeRunner wrote:Just curious? Does this thing hold up good on the roof or does it swing all over the place?

Thanks

I would imagine it would swing all over. I have an NMO27 and NMO150 with shorter rods and they're very flexible.

Puts less strain on the mount but makes me wonder what it does for performance.

jhooten · Post by **jhooten** » Fri Jul 23, 2004 8:23 am

RidgeRunner wrote:Just curious? Does this thing hold up good on the roof or does it swing all over the place?

Thanks

It is no worse than a NMO150 with a full 49" rod. The "lay back" of it and the the NMO150 at highway speeds are almost identical from the pics the other half took of the truck on the highway. I have even been a little harder on it than normal (driving into tree branches instead of around them) to see what it will take and it hasn't broken yet.

Best NMO mount loaded 1/4 lowband antenna...?

Best NMO mount loaded 1/4 lowband antenna...?

maxrad

ball and spring

Re: ball and spring

just curious

lowband

Re: just curious

Re: just curious