Debating on which antenna to use for mobile

[SCPD]

I placed this in the commercial area because the radio used is a astro spectra mid power in a vehicle. My current antenna which is the Comet SS460SB sucks because it's not widebanded at all the spring on it is for looks. Now I don't know which one to get but these are the two I'm focused on: Antenna Specialists ASPE7495 or Diamond M285S. The ASPE7495 has a spring which would benefit me during off-road sessions. I have many diamond antennas with great performance some did break tho. I can't seem to find any real reviews on antenna specialists antennas.

 

[mmckenna]

Given the choice between the two, I'd go with the Antenna Specialists. NMO mount is going to be much more universal and is really designed as a mobile antenna mount. The UHF mount for the Diamond, in my opinion, is a very poor design choice, and not at all suited for mobile use. I know the amateurs like UHF connectors, but I never understood with much better options out there why this type of mount is still in use.

The AS is a quarter wave, and I personally really prefer those for mobile use. The nice even radiation pattern works well in the hills and mountains here in California. Just take a look at what CalFire and your local agencies use. CalFire used quarter wave and I'm sure you'll find the locals do too. The lower height will be a benefit off road, as will the spring.

The Diamond, being a 5/8 wave will probably work fine, and they are usually flexible enough to handle off road use. I'm not a big fan of Diamond, I think of them as an amateur grade antenna, and not really designed with the commercial use in mind. Likely it would be just fine.

I've never heard an improvement in signal between a 5/8ths wave and a 1/4 wave. I know on paper it's supposed to be there, but I just don't hear it. Maybe out on the flat plains of the midwest it makes a difference, but here in the hills, mountains and valleys I just don't personally see the improvement.

To top this all off, a quarter wave antenna is going to have more useable bandwidth as compared to the 5/8ths. In other words, the acceptable SWR will be spread across more of the spectrum on a quarter wave than it will be on a 5/8ths wave. If you only operate in the ham bands, not so much a big deal. If you get outside the ham bands, I'd suggest the quarter wave will be a better performer, at least on the transmitting side.

My opinion is the Antenna Specialists is the better choice of the two. Don't forget to look at other brands, I've personally had very good luck with Larsen, in fact I use them pretty much exclusively at work and I've not had issues with them. I've been using them for my own stuff for about 20 years with good luck also.

 

[kayn1n32008]

Given the choice between the two, I'd go with the Antenna Specialists. NMO mount is going to be much more universal and is really designed as a mobile antenna mount. The UHF mount for the Diamond, in my opinion, is a very poor design choice, and not at all suited for mobile use. I know the amateurs like UHF connectors, but I never understood with much better options out there why this type of mount is still in use.

The AS is a quarter wave, and I personally really prefer those for mobile use. The nice even radiation pattern works well in the hills and mountains here in California. Just take a look at what CalFire and your local agencies use. CalFire used quarter wave and I'm sure you'll find the locals do too. The lower height will be a benefit off road, as will the spring.

The Diamond, being a 5/8 wave will probably work fine, and they are usually flexible enough to handle off road use. I'm not a big fan of Diamond, I think of them as an amateur grade antenna, and not really designed with the commercial use in mind. Likely it would be just fine.

I've never heard an improvement in signal between a 5/8ths wave and a 1/4 wave. I know on paper it's supposed to be there, but I just don't hear it. Maybe out on the flat plains of the midwest it makes a difference, but here in the hills, mountains and valleys I just don't personally see the improvement.

To top this all off, a quarter wave antenna is going to have more useable bandwidth as compared to the 5/8ths. In other words, the acceptable SWR will be spread across more of the spectrum on a quarter wave than it will be on a 5/8ths wave. If you only operate in the ham bands, not so much a big deal. If you get outside the ham bands, I'd suggest the quarter wave will be a better performer, at least on the transmitting side.

My opinion is the Antenna Specialists is the better choice of the two. Don't forget to look at other brands, I've personally had very good luck with Larsen, in fact I use them pretty much exclusively at work and I've not had issues with them. I've been using them for my own stuff for about 20 years with good luck also.

I will echo everything McKenna has written. Stay away from UHF mounts. NMO IS the industry standard for a reason.

1/4 wave antennas are much more broad band, another choice would be a 1/2 wave if you need wide band. I use and have used Larsen, PCTel, Sinclabs Excelsior series, and Maxrad. While none have had a spring, most can be purchased with it. All these brands good results. I work in the oilfields of western Alberta. A Baja racing truck does not punish the antennas like pounding down some of the ****ty lease and logging roads that I drive.

I have not used antenna specialists so I can not comment with respect to them.

I can not stress this enough. Hammy antennas are CRAP, do not have the bandwith and will not last like a Larsen, or any of the other brands listed.




Sent from an unknown place...

 

[SCPD]

Thank you for the replies. The AS is what I'm going to get.

 

[SCPD]

WHOOPS I GAVE THE WRONG ANTENNA MODEL NUMBER for the debate hahaha
THIS is the other antenna im looking @ over the diamond

Antenna Specialists ASP7455 [A/S ASP7455] - $36.95 : The Antenna Farm, Your two way radio source

 

[mmckenna]

OK, pretty much all I said above is the same, with the exception of the gain vs. useable bandwidth of the antenna.

Still, you are comparing an antenna that is more along the professional line to an amateur grade antenna. As Kayn... said above, there really isn't a comparison. While the Diamond might look similar, the very fact it uses a UHF connector as the base is a bad sign. It might work just fine, but just be aware that Diamond is an amateur oriented company, and Antenna Specialists has a background in building commercial grade stuff. The NMO mount alone would be enough to convince me which one to choose.

The Antenna Specialist would be fine, although I'd still suggest looking at Larsen, Antennex. ComTelCo, etc. All should be pretty close and similar specs, pretty much aesthetics is the difference.

Good luck!

 

[traumacop]

Larsen NMO150/450/800

Larsen NMO150/450/800 [NMO150/450/800] - $29.95 : The Antenna Farm, Your two way radio source

I have had one of these for about 6 months and it performance is fantastic.

I was reluctant due to it's small size, but since many agencies are migrating from low band to 800 I thought I would give it a try after reading some reviews. Glad I did and it's worth twice as much as I paid for it. The good thing is I can't use it to transmit on if needed.

 

[SCPD]

Larsen NMO150/450/800 [NMO150/450/800] - $29.95 : The Antenna Farm, Your two way radio source

I have had one of these for about 6 months and it performance is fantastic.

I was reluctant due to it's small size, but since many agencies are migrating from low band to 800 I thought I would give it a try after reading some reviews. Glad I did and it's worth twice as much as I paid for it. The good thing is I can't use it to transmit on if needed.

I'm going to just get a Larsen NMOQW144.

 

[mmckenna]

Good choice. At less than $10, it's a really good place to start. If it works, call it done. If not, you are only out ten bucks.

I've been running those basic "chrome nut" type antennas for a long time without issue. With any mobile antenna, even this one, it's a really good idea to remove it and clean underneath it now and then. While they are well sealed, the contacts can get crudded up over time.

 

[SCPD]

Good choice. At less than $10, it's a really good place to start. If it works, call it done. If not, you are only out ten bucks.

I've been running those basic "chrome nut" type antennas for a long time without issue. With any mobile antenna, even this one, it's a really good idea to remove it and clean underneath it now and then. While they are well sealed, the contacts can get crudded up over time.

I use dialectic type grease on my antenna connections. Its clearish looking and keeps water out(I think) and no ceasing. The antenna will work for now cause the diamond I'm using now looks like a joke.
I'm not a fan of chrome but I will just plastidip the Nut and whip if need be. I appreciate everyone's help on my decision. What I'm trying to find is a 1/2 or 5/8 (doesn't matter really) antenna that is NMO that has a spring.

 

[mformby]

I would look at the Maxrad line also. They make some HD antennas with a HD shock sprint that will take a beating. Unity or gain available.

 

[BirkenVogt]

Over years the chrome nut antennas tend to get water in the connection. It goes past the whip in the top of the hershey's kiss of rubber and corrodes the contact.

The Laird B132S or equivalent Maxrad or other has what looks like a coil at the base but in reality it is just a chunk of round brass with a plastic cover and the spring is a necessary, part as I think you know. This is used to thicken the bottom of the antenna and give broader bandwidth although the cheap QWs have a pretty broad BW as well.

I do a lot of installs on fire vehicles which go from the sub 151 freqs to almost 174 and the B132S is necessary to get an acceptable SWR across that very broad range. I say acceptable because it is very tricky to get the length just so. I use a graphing analyzer and set up the length so that the SWR is equally poor on my highest and lowest desired frequency. Usually I can get less than 2.5:1 and often below 2:1.

If you use a 5/8 wave like the ASP7455, then you are going to have a very narrow bandwidth. The performance is quite a bit better than a QW but it is only good for maybe 3 MHz of bandwidth. I use them whenever I can which is usually for a trunking customer where the transmit is always within a few MHz of center.

I have not been a fan of 1/2 wave antennas in general. My experience with them is with the B1442N which is a 2.4 dB no ground plane antenna which we sometimes use on fiberglass truck roofs. They give good SWR but for some reason the receive performance does not seem very good. I don't find much call for them, though, so I am not really sure. Usually it is a 1/4 or 5/8 wave for me.

 

[DisasterGuy]

In general you can't go wrong with Laird or Maxrad. They are the only mobile antennas that I spec and install.


Sent from my iPhone using Tapatalk - now Free

 

[KI4VBR]

Mount With Quality Cable

I dont want to hi-jack the message here, but are there mounts or options that will allow a higher grade coaxial cable to be run to the radio? It seems that most antenna mounts have run-of-the-mill coax cable connected. I guess for lower frequencies, that is OK. However, when most of the traffic is sitting above 700 mhz, cable quality can be a factor in signal quality and SNR.

I realize it is just a short run from the antenna base to the radio, but I was wondering if there are options for better cable. Obviously I dont want to put 1/2" hardline through the vehicle, but there has to be a high-quality medium thickness cable offering better specs.

Thanks,
Vince
KI4VBR
EL88ob

 

[DisasterGuy]

I dont want to hi-jack the message here, but are there mounts or options that will allow a higher grade coaxial cable to be run to the radio?

Vince, This is what I use for 800MHz installs. It uses a high quality Teflon RG-58. Laird Technologies MBF 0-1000 MHz, 3/4" Brass Mount, Teflon, No Connector | TESSCO

 

[mmckenna]

I dont want to hi-jack the message here, but are there mounts or options that will allow a higher grade coaxial cable to be run to the radio? It seems that most antenna mounts have run-of-the-mill coax cable connected. I guess for lower frequencies, that is OK. However, when most of the traffic is sitting above 700 mhz, cable quality can be a factor in signal quality and SNR.

Yep, there are many different options if you go to TESSCO - Wireless & Mobile Communications Products: Antennas, Cable, Towers, Test Equipment, Tools, Mobile Phone Accessories and look at their mounts. RG-58 dual shield, LMR-200, LMR-240, etc. With the usually short cable runs, it doesn't always add up to a big difference, but the prices are usually within a $1 or so of each other, so it isn't a budget buster.

 

[KI4VBR]

Thanks to both of you for info on Tessco. I have dealt with them in the past for wireless projects I do with my business, but never think of them for my hobby needs.

The 3/4" brass mount that was mentioned above....do they have something similar where I dont have to ut a hole in the car? Mag mount with the same cable?

Thanks much!

Vince
--... ...--

 

[BirkenVogt]

Vince, This is what I use for 800MHz installs. It uses a high quality Teflon RG-58. Laird Technologies MBF 0-1000 MHz, 3/4" Brass Mount, Teflon, No Connector | TESSCO

We have settled on the NMOKUD up to and including 800 MHz. It comes with a good quality foil shield cable and is a heck of a lot cheaper than that above. Some may not like the short section of open line at the underside of it but it does not seem to matter any in actual practice. I always cut the cable as short as practical to minimize losses but even with the full 17' it is fine.

NMOKUD Product Detail

Also try Talley as an alternative to Tessco. They are usually a few dollars cheaper and get our orders first.

Don't worry about cutting a hole in the car. It does not affect resale from what I have ever been told and they sell a rubber plug that fits beautifully and does not leak when you are done with it. Mag mounts scratch the paint and IMO are worse than a nice hole.

K35 Product Detail

Here are the mag mounts.

Talley Inc. | Online Store - Search Results

 

[mmckenna]

Yep, or bracket mounts. It isn't hard to take an existing NMO mag mount and replace the cable with something of your liking.