Performance degradation using stubby antenna?

[N4DES]

We measured the field difference between the (Motorola) stubby and standard size antennas and was a 7db difference between the two. When you factor in body shielding (when worn on the belt) and varying building density losses it could make a user inoperable, especially on talk-in.

The only stubby antenna configuration that I approved for field usage is if the radio was worn a tactical vest.

 

[ElroyJetson]

I've never seen performance data on this. When comparing radios with mounted antennas vs. radios with speaker-mics that have the antenna on the speaker-mic, is the improved line of sight at shoulder height enough to offset the connector and cable losses of the speaker-mic-antenna system?

 

[Peter_SD911]

Stubby antennas are PROHIBITED on the San Diego County RCS 800mhz system.
Poor performance is the reason.

Yup...
It's a rule.

 

[PACNWDude]

I deal with this often, being responsible for fire radios across the country, some used in more rural areas, and others in industrial manufacturing environments.

End users often fold the antennas over, using rubber bands, tape or cable ties to bend them in half. Others cut the antenna to a shorter length, sometimes adding heat shrink tubing or dust caps to their ends.

The fatter the end user, the more they complain about the antenna stabbing their gut.

I now keep an "Antenna Wall of Shame" display with all the different types of ways people tried to get a shorter antenna, and then complain about signal quality or lack of radio coverage. Corporation wide, (yes private firefighting organization), stubby antennas are available but issued only under very stringent circumstances. This is for XTS2500/APX6000XE/APX8000XE radios.

A radio shop co-worker carries his APX4000 with a stubby antenna, but has now been guilted into keeping his longer antenna, for when he gets to fringe areas and needs the longer antenna. Then, for simulcast site maintenance, some have had to be told to remove their antenna while under the "umbrella" of the site for testing. Even with a GROL requirement for radio related work, some people need to be shown more than told.

As for end users, the worst are the amateur radio types that think they know commercial radio, becuase of the amateur license, and you then see their APX8000XE with a three foot long whip bought off Amazon.....who then claim that they get better signal (but at least that antenna is more flexible.......Stico does get some money for some use cases too - mostly vehicle use).

My mantra is that you should use the antenna made for the radio, so Motorola radio means a Motorola antenna, and not a cut down or bent over one. Stubbies are for the office dwellers (in high RSSI areas), not those in the field and out and about.

 

[ElroyJetson]

I can't tell you how many times I've had to deal with customers who had mangled antennas who were complaining that their radio didn't have much range. I always told them the same thing: The antenna is the most important part of the radio. It won't perform better than the condition of the antenna. So don't fold, bend, twist, mangle, cut, or in any way damage the antenna. Don't put things on it. Keep it in the state it was when it was brand new. Or I'll charge you a bench labor fee every time you bring back a radio to me with an abused antenna.

Some people are immune to the idea of "listening and following insructions" but most of them got it.

 

[mbnv992]

Speaking of stubby antennas - I see LAPD has the super short XTS style UHF stubby antennas on a lot of their apx8000’s. Some even have the old XTS UHF whip on them, but very very rarely do I see an LAPD officer with the actual all band APX8000 whip antenna on their radios. Usually it’s the stubby UHF.

 

[APX8000]

"The only stubby antenna configuration that I approved for field usage is if the radio was worn a tactical vest."

I wear my APX on a tac vest directly in front with a stubby and have actually seen BETTER performance compared to it on my belt while seated in a vehicle. BUT, take that same radio with the same stubby and throw it in the cupholder in the same vehicle, and I've seen reduced coverage compared to a whip.

As what others echoed, you have everything from system coverage performance during testing with a whip vs stubby, to real world folks bending them so they don't get poked. You have APX8000 users throwing 7/800 stubbies with radios programmed with multiple different bands for interoperability. Needless to say, it will be a mess when you add the user to the radio in all different scenarios.

 

[PACNWDude]

This thread made me check my own work APX4000 and antennas vs. RSSI. I am only about 500 feet from the GTR8000 stack, and here were my RSSI results. 179 with the long antenna for 7/800 MHz APX4000. 137 for the stubby antenna, and 58 with no antenna.

 

[NVAGVUP]

I explain it like this. (LE perspective)

I will ask "What caliber is your service weapon"? (I already know the answer. 9 mm)

Me. "Using the regular [longer] antenna is equivalent to carrying a 9mm as a service weapon. Using a stubby antenna is equivalent to carrying a 25 caliber. In many instances, either will do the job. But if my life depends on it, I know which antenna I want on the radio".

 

[MTS2000des]

I had that exact argument with a SWAT officer who claimed his radio not working well was a "safety issue" and sent a scathing email to his LT. I responded and said bring radio to my office that following Monday.

He had some low rent aftermarket choad antenna, told me the location of where he was. I asked him to show me how he carried the radio. He had his APX6000 on the lower back of his duty belt, inside a vehicle. Of course it is going to bonk out of range and high BER. I removed the unauthorized antenna, and used the same analogy of making unauthorized changes to his service weapon and not knowing how to properly operating his service weapon.

He never could explain why he refused to use the mobile radio in his vehicle which was perfectly operational.

 

[nokones]

I had that exact argument with a SWAT officer who claimed his radio not working well was a "safety issue" and sent a scathing email to his LT. I responded and said bring radio to my office that following Monday.

He had some low rent aftermarket choad antenna, told me the location of where he was. I asked him to show me how he carried the radio. He had his APX6000 on the lower back of his duty belt, inside a vehicle. Of course it is going to bonk out of range and high BER. I removed the unauthorized antenna, and used the same analogy of making unauthorized changes to his service weapon and not knowing how to properly operating his service weapon.

He never could explain why he refused to use the mobile radio in his vehicle which was perfectly operational.

Also, Officers need to stop wrapping the speaker mic cable coils around the entire antenna.

 

[N4KVE]

Also, Officers need to stop wrapping the speaker mic cable coils around the entire antenna.

Or hanging their car keys on the antenna.

 

[nokones]

Or hanging their car keys on the antenna.

And I've been guilty of that many decades ago. Those antennae are so handy.

 

[N4KVE]

Speaking of stubby antennas - I see LAPD has the super short XTS style UHF stubby antennas on a lot of their apx8000’s. Some even have the old XTS UHF whip on them, but very very rarely do I see an LAPD officer with the actual all band APX8000 whip antenna on their radios. Usually it’s the stubby UHF.

I don’t know if they only use UHF out there, but if they do, wouldn’t the dedicated old style XTS UHF whip work better than the 8000 VHF, UHF, 700/800, GPS antenna?

 

[nokones]

I don’t know if they only use UHF out there, but if they do, wouldn’t the dedicated old style XTS UHF whip work better than the 8000 VHF, UHF, 700/800, GPS antenna?

LAPD is UHF T-Band (500 MHz) and LA Sheriff is also UHF T-Band (482 MHz) with a 3 Meg off-set. Several of the locals are also UHF T-Band (470 MHz), and some also UHF 460 MHz. I haven't kept up with that area much in the last couple of decades, so I don't know how many have migrated to 700/800 MHz. I'm not sure who is left on VHF High band (150 MHz) anymore but I'm sure there may be several. Its been several decades since I participated on the frequency coordination committees for Northern & Southern California.

 

[sammyg512]

It depends on the site, I prefer the Stubby as its smaller and more compact. Looking at it from an events perspective, nearly all radios used are UHF with a stubby, as repeaters are installed around the site to ensure radios are allways able to connect. I remember at one event, we used VHF with Whips, due to the size of the site and the terrain.