Stubby VS. Full Length Antennas

Post by **Code3Response** » Sun Feb 24, 2002 2:30 pm

What do you think? Is there a dramatic difference in RX and TX performance if switching from a regular length to stubby antenna on my VHF and UHF saber. Anyone have and stubby antennas for sale? Thanks!

10-95 · Post by **10-95** » Sun Feb 24, 2002 2:33 pm

Stubbys are alright if you are well within the coverage area of your repeater or if you are using a vehicular repeater. For law enforcement use use a regular antenna, a bad signal could be the death of you on a traffic stop gone bad.

Frank

Monty · Post by **Monty** » Sun Feb 24, 2002 2:59 pm

Hi Matt:

What is really important is the
quality of the radio. Manytimes
if you have a Superior Quality
Radio, it does not make all that
much difference.

Small antenna's for the proper
application does work well, Full
lenght antennas will work better.

However, The local State, City, County
( here in SD )
chose the lower profile antennas, as full
lenght antennas will tend to break apart
in the center, and also give nervious persons
a place to chew off the tops of the longer
style antennas.

Both work very well for thier intended
applications.

Use Injected Molded Antennas ( Over dip Coated Styles ) Molded Antennas
tend to work well, and last a long time.

Monty

<font size=-1>[ This Message was edited by: msisco9939@aol.com on 2002-02-24 18:03 ]</font>

Twisted_Pear · Post by **Twisted_Pear** » Sun Feb 24, 2002 5:29 pm

Welp, the whips typically give you 3.5dB gain (Double your output wattage) whereas the stubbies are unity gain. It's all in whether you need that extra power output or not.

RFdude · Post by **RFdude** » Sun Feb 24, 2002 6:01 pm

Whoa! 3.5 dBd gain (or even unity!)from an HT antenna? Tell us the make and model and we will all beat a path to the vendors door!

For UHF, at best you will have a 1/4 wave radiator for a full length whip...so it is 0 dBd gain at best. Unfortunately, the radio isn't a good ground plane and the users coconut (or waist) is coupled in the near field. VHF or any stubby isn't even a 1/4 wave, but a helical coil, so the gain will be negative dBd.

Does anyone out there have some confirmed gain (loss) numbers relative to a dipole?

NodrogCop · Post by **NodrogCop** » Sun Feb 24, 2002 7:44 pm

I'm using Antenex's stubby VHF now on my HT1000, and haven't noticed a difference. However, I'm in the middle of a good repeater system, and even the tactical freq's (radio-to-radio) are good.

Home is a fringe area, though, and I do notice a difference. I still keep the longer one in my desk.

FWIW, I'm in law enforcement, and don't have a problem getting out when things get a little "complicated".

I got my antenna thru Chiefsupply.com

jim · Post by **jim** » Sun Feb 24, 2002 8:02 pm

I just installed an Antenex stubby on my Vertex VX10 UHF and there's no difference. On my GP300 UHF, there IS a decrease of performance.

WTF????

Nickdap · Post by **Nickdap** » Mon Apr 15, 2002 2:22 am

Hey All,

Forgive me but I know little of HT antennas and the theory. But what is the difference between a stubby VHF from antenex and a UHF stubby. Whats the go inside the antenna? The reason I ask is im assuming the VHF stubby does not have a helical wind in it.

Basicly when i bought my radio ex gov, (VHF Jedi) it came with a UHF wide band (grey dot) whip. Then i bought a wideband vhf and whoa! thats one bigg ass antenna! The uhf I never really tried for fear it could damage my radio (would it?), but back the the main reason for the post what is the electrical difference between a vhf stubby and a VHF whip?

Thanks for your help...again
Nick

Jim202 · Post by **Jim202** » Mon Apr 15, 2002 5:16 am

For what it is worth, many moons ago, there was this public safety UHF repeater system. The foot patrol was having a real hard time even hearing the system inside the mall they had to patrol. In checking out the system, we found that all the portables were using the short stubby antennas.

Had several of the portables try the full length UHF antenna and see what happened. The same day word came back that they could now hear the repeater and even get back to the dispatcher from inside the mall.

Part of this story will be based on just how the radios are made. Back in those days, the radios had a metal case around them. As such they tended to have some sort of a ground plane to have the antenna work with. Each of the radios today will act different with different antennas.

Best way to tell if the long antenna will make a difference is to try it. You won't see any difference in a good coverage area. Need to get into the fringe coverage area and make the test. Pick several spots where you can just hit the repeater. Mark the spot and then try it looking in different directions. The direction to the repeater and the way your facing make a large difference in the funtioning of the radio system.

The location of the radio makes a difference. Hanging on a belt while trying to use a speaker mic is not going to work very well in a fringe area. Need to get the antenna up high as possible and free of the body. The body acts as a big sponge to absorb much of the energy.

Just a few thoughts and tests from over the years.

Jim

Nickdap · Post by **Nickdap** » Mon Apr 15, 2002 5:20 am

Thanks very much jim
regards
nick

Tom in D.C. · Post by **Tom in D.C.** » Mon Apr 15, 2002 5:30 am

For those who don't know it already, a UHF quarter wave is about, I repeat "about," six inches long. Therefore the typical UHF rubber antenna, unless it's a shortened version, is actually a pretty good performer if you go by the book. However, a VHF quarter wave is in the area of 16 to 18 inches long so ALL of the rubber antennas are compromise versions of the quarter wave length. The other factor the mfrs. strive for is to present the proper load to the radio, which in most cases is about 50 ohms. So, somewhere between the point where you connect a 50-ohm resistor or a full quarter-wave antenna to your radio lies the compromised performance of the shortened antenna. My experience has shown exactly what others have said above: In the primary coverage area of your repeater it usually doesn't hurt you too much to use a shortened antenna, but on the fringes, and for simplex operation, the longer the antenna the better it will perform.

Tom, W2NJS
...in D.C.

Post by **wavetar** » Mon Apr 15, 2002 7:25 am

I read an article on Fractal Antennas a few years ago. Don't be surprised if these start showing up on the inside of certain makes of radios to try & eliminate the external antenna. Some cellulars & PCS already have them. It's makes for interesting reading.

http://www.fractenna.com/

http://www.sciam.com/1999/0799issue/0799techbus3.html

Todd

Jonathan KC8RYW · Post by **Jonathan KC8RYW** » Mon Apr 15, 2002 11:58 am

Anyone remember the HT-220 Public Safety version? It was only made for UHF. The speaker-mic also hoisted the antenna.

I know an extra two feet of height from the waist may not seem like much, but I'm sure it helped in fringe areas.

Post by **alex** » Mon Apr 15, 2002 12:49 pm

One other point to consider - the antenna on the speaker mic will probably get better reception performance, but might not get better transmit performance.

The reason for the better recieve is because you don't have the antenna next to your waist, and sometimes scrunched under your arm. Remember, the body is about 70% water and RF+water don't really mix.

Interms of transmit, the cable would have to be rated at good enough loss for it to be that far away. That's prob. why the cables aren't coiled.

-Alex

Tom in D.C. · Post by **Tom in D.C.** » Mon Apr 15, 2002 2:23 pm

Alex: I've used a TNC VHF stubby antenna on a Saber Public Safety speaker/mic and it apparently works. I don't know about efficiency, and I only use it at hamfests for simplex comms. Your question about the coiled cord is correct; the straight cord is used on the Public Safety mics, otherwise the coil would do strange things to the RF traveling up to the antenna on the mic housing. I've never been able to figure out why Motorola never made a PS VHF speaker/mic, though I'm making one work okay, apparently, as I said above.

Tom, W2NJS
...in D.C.

Post by **wavetar** » Mon Apr 15, 2002 3:39 pm

One customer recently tried out 6 of them with their 800MHz XTS3000 radios on our SmartZone system. They consistently read 20-30 lower for the site RSSI compared to a regular antenna. It really seems to me that the additional height & distance away from the body would be more than offset by the extra connectors, cable length, etc. That is my only experience with them though, no other testing. I figure they must work in some applications, or they wouldn't have been around so long...

Todd

USPSS · Post by **USPSS** » Mon Apr 15, 2002 4:19 pm

First of all, Antennex and Maxrad's portable antenna's are made by Centurion.
UHF 6' long antenna's are basically a piece of piano wire hooked to the connector, the stubby is a helical design. and is shown to be anywhere from -3 to -6 dbd based on frequency, add the location on the side of the body and it is commonly -20dbd.

Vhf 6' are helical wound, stubby are tight helical some with a cap. installed.

The longer antenna's are better in both bands but on the side of the body you will probably see no diference if it is touching or very close to the body, if it is 2-3 inches away the longer units will perforn better.
The public safety mic will perform better because of location of the antenna based on height. The reason the VHF was never made was the impedance in the unit could not be brought to 50 ohm, so if you are using a VHF antenna on one you might be harming your finals.

Sorry for being so long.
Stan http://www.uspss.com[/url]

Tom in D.C. · Post by **Tom in D.C.** » Tue Apr 16, 2002 6:44 pm

Today I ran a UHF Saber and a VHF Saber into a Bird 43 wattmeter with appropriate (correct range) slugs in the Bird. On 146.520, using a public safety mic with its TNC output fed to the Bird it showed no reflected power. On UHF, at 446.000 mHz, it likewise showed no reflected power. The forward power in both experiments was normal, between 3 and 6 watts, and I was not really concerned with that level. The load used was a standard HP N-connector. 50-ohm, 15-watt dry load.

Tom, W2NJS
...in D.C.

Jaqx · Post by **Jaqx** » Wed Apr 17, 2002 5:57 pm

I've used a VHF MT2000 extensivley with the wide-band, regular length and a couple of stubby antennas.

There is a slight difference between the HUGE wide-band antenna dn he regular length. It's not enough of a difference to justify the hole that gets worn into your armpit.

There is a signifigant difference between the stock antenna and the shorter stubby's. The biggest difference I've seen is the receive when the radio is on the hip. If the stubby is on the hip and you're in a fringe area the transmission is often lost.

I have the public safety mic and the normal mic and there is a big difference beteween them. I use a Centurian stubby VHF antenna on the public safety mic and it talks great. Especially in a vehicle, having the antenna over the shoulder makes a world of difference.

Bottom line for me, normal length antennas get the job done and that's what I have moved toward. I've found that for emergency service communications the stubby antenna in any use except on a public safety mic, is not the way to go. Citizens are counting on these users to hear the transmissions and talk to each other and comm. centers. The three inch savings just isn't worth it

RADIO_MAN · Post by **RADIO_MAN** » Wed Apr 17, 2002 6:42 pm

Stubby antennas no way even come close to the regular stock antenna on the portables. I think half of the people want stubbies just so they can have a radio that looks more pleasing and official. However there are people who have a general complaint. THE ANTENNA IS IN THE WAY. If you use a stubby antenna instead of a stock antenna you will notice a difference.

Case and Point

I had a rather large federal government customer come in and purchase around 75 stubby antennas for their field radios. This customer wanted the radios to not be so easily recognized, (However I think no matter what antenna you put on an Astro Saber it wont make a difference) I advised the customer that the chances for communications problems would be greatly increased but they insisted on using smaller antennas. About a week later the customer brought back all but 2 of the stubby antennas, the complaint was that there was a great increase in personell not being able to connect to the Digital System. After the antennas were replaced to their original configuration all was well. This customer apologized and promised never to second guess experience and / or expertise.

R

Nickdap · Post by **Nickdap** » Wed Apr 17, 2002 8:19 pm

great story, Well I think you guys have convinced me. The Wideband VHF is just TOO big, but you cant argue with the laws of physics. I would just want to try a stubby, as i wouldnt mind the odd change over. The only this is there isnt a wide band stubby. Would SWR affect a Jedi hand held? I'm not talking efficency I'm talking actual damage to the finals or somthing.

I'm not PS so I dont have to worry about things of that nature so I'm still kinda interested for when im runnning close range simplex or working near a satellite rx site.

I've found two antennas from Centurion.com both are helical design.

Model EXB 1/4 wave looks around 5" and has a gain of -2 db
Model SXD 1/4 wave capless around 5.5" and has a gain of 0 db

look good, does anyone have any experence with these? By the way I was quoted USD$40 shipping to aust for a similar antennex model from a web based business, doesnt that seem a bit high for a USD$20 antenna. From US to Sydney?

Thanks for the help guys, been a good read
Nick

April · Post by **April** » Thu Apr 18, 2002 7:23 pm

I think that price is the retail, not jober.

The new antenna for the VHF HT750 (from Motorola)is a little longer at 7 1/2" and works MUCH better than the helical 5 and 6 inchers.
I have several customers who use the Wideband Antenx at 7 3/4" have very good reports even the SAR and SARK9 people who use speaker mics and headsets and the radio on the belt have a MUCH better result and use 145 and 155 in the same radio.
On UHF, I have always used the 6" flexible whips. the stubies are a terific loss on UHF, way more noticable.

Astro_Saber · Post by **Astro_Saber** » Thu Apr 18, 2002 7:40 pm

http://accesssecure.mot.com/Accesspoint ... t+hmij8682

at the bottom, i use a stubby for my vhf saber

craig · Post by **craig** » Fri Apr 19, 2002 6:31 am

I couldn't agree more with Jaqz, I too have used a MT2000 VHF extensively for public safety. The public safety mic is the only way to use a stubby VHF antenna, otherwise fringe area signals are lost totaly. The stubby and PS mic really help in the car, which is a must here. Sometimes I have to put my mobile radio on the emergency network to monitor and use my MT2000 to contact dispatch. Regular length antennas are the way to go otherwise.

Craig

woody · Post by **woody** » Sat Apr 20, 2002 9:30 am

I have several stubby uhf motorola saber 403-433 antenna's most 8-9 in condition. Would like to trade for whip antenna.

Astro_Saber · Post by **Astro_Saber** » Sat Apr 20, 2002 10:49 am

woody wrote:I have several stubby uhf motorola saber 403-433 antenna's most 8-9 in condition. Would like to trade for whip antenna.

i got a uhf with a small ball on the top i dont use is that what your loolking for?

kens · Post by **kens** » Sat Apr 20, 2002 4:28 pm

For VHF I have used the Larsen "Helical Quarter Wave" (HQ) antenna with better results than factory antennas. It looks like a vhf stubby with a 1/4 wave uhf added on the end. It is about 10" long and some users complain about the length but it is about 1/2 the length of a 1/4 wave vhf whip.

Stubby VS. Full Length Antennas

Stubbys are Junk

Jaqx