To the board:
I will be putting a GMRS repeater on the air in the next couple of months, and am looking for some suggestions for a reasonably priced repeater antenna that will work well in my application.
My house sits on a hill a bit above the average terrain, and I will be installing the antenna on a 5 ft. mast atop the highest point. This will place the antenna about 20ft. above ground, and about 150 ft. above the average terrain.
The repeater is a GR300 at 45 watts out, and I will be purchasing a duplexer (I don't know which one, yet). I don't expect much interference, although, there are cell towers within 1/2 mile from my house.
My thoughts are to go with a 4-stack vertical di-pole (not sure of the technical name for this) because they have a pretty wide usable bandwidth and I have heard that they can pull in weak signals better than other types of antennas.
I am interested in what others have used, and what type of performance I should expect.
Thanks in advance,
Yosh
KD6PXE
WPOL560
Which Repeater Antenna???
Moderator: Queue Moderator
Hi:
When it comes to performance, a correct
antenna ( and transmission line ) can make
all the difference in the world.
Now comes the bad news....Good Commerical
Antennas like a Super Station Master and
even a DB-413 can be expensive.
I have a Brand New DB-413 In the Box if you
are Interested, but even those are around 500.00. However its a 10 DB Gain antenna.
Comes the Lower Priced ( But they do work very well ) is the Antennx Style of antennas
and they can run from 250.00-350.00 and I have those to.
Depending on you expectations, you should be
able to get a 15 to 25 Mile radius from
you location with either one with a companion 25 watt/45 watt mobile.
So, if you want something Brand New, you
might email me direct @ [email protected]
as I also have Duplexers as well along
with 1/2 Celwave and 7/8 Celwave cable
if you wish to go 1st class
Monty
When it comes to performance, a correct
antenna ( and transmission line ) can make
all the difference in the world.
Now comes the bad news....Good Commerical
Antennas like a Super Station Master and
even a DB-413 can be expensive.
I have a Brand New DB-413 In the Box if you
are Interested, but even those are around 500.00. However its a 10 DB Gain antenna.
Comes the Lower Priced ( But they do work very well ) is the Antennx Style of antennas
and they can run from 250.00-350.00 and I have those to.
Depending on you expectations, you should be
able to get a 15 to 25 Mile radius from
you location with either one with a companion 25 watt/45 watt mobile.
So, if you want something Brand New, you
might email me direct @ [email protected]
as I also have Duplexers as well along
with 1/2 Celwave and 7/8 Celwave cable
if you wish to go 1st class
Monty
-
MT2000 man
- Posts: 1307
- Joined: Tue Sep 04, 2001 4:00 pm
- What radios do you own?: XTS5000R, Astro Saber III, I
Darn, Monty's correct again.
I would look at the Cushcraft/Signals 4504S offset or omni four bay exposed folded dipole antenna at $250
This is a broad band antenna if you are on a tight budget. Also look up Comtelco, I have had very good results with their BS & BSXL series fiberglass antennas. They have tubular dipole elements instead of just a peice of 16 gague wire with a couple of curly cues like the Antenex and Maxrad does.
http://www.comtelco.com
Ues a good cable, Times LMR400 at minimum.
And type N connectors of good quality.
I would look at the Cushcraft/Signals 4504S offset or omni four bay exposed folded dipole antenna at $250
This is a broad band antenna if you are on a tight budget. Also look up Comtelco, I have had very good results with their BS & BSXL series fiberglass antennas. They have tubular dipole elements instead of just a peice of 16 gague wire with a couple of curly cues like the Antenex and Maxrad does.
http://www.comtelco.com
Ues a good cable, Times LMR400 at minimum.
And type N connectors of good quality.
Hi Yosh
I agree with Monty, a nice db products antenna and some 7/8 hardline if possible. One thing I've found out is do right the first time and you won't regret it. You can further investigate their antennas at this url.
http://www.decibelproducts.com/
Doug
I agree with Monty, a nice db products antenna and some 7/8 hardline if possible. One thing I've found out is do right the first time and you won't regret it. You can further investigate their antennas at this url.
http://www.decibelproducts.com/
Doug
-
raymond345
- Posts: 268
- Joined: Sat Sep 22, 2001 4:00 pm
Yes, the GMRS split that I will be using is 462.575 / 467.575. The reason for wanting a wide-band antenna is so that it may double as a 70cm Ham repeater/base antenna if I have the desire to change it in the future. Although, its primary use will be GMRS at this point.
Actually, now that I think about it, the antenna doesn't have to be TOO wide banded. Maybe 10 MHz at the most (with less than 1.5:1 VSWR), but it would be nice to have room to adjust the center point from the 465 center on GMRS to the 445 center on 70cm ham band (I don't use below 440 MHz).
Thanks,
Yosh
KD6PXE
WPOL560
Actually, now that I think about it, the antenna doesn't have to be TOO wide banded. Maybe 10 MHz at the most (with less than 1.5:1 VSWR), but it would be nice to have room to adjust the center point from the 465 center on GMRS to the 445 center on 70cm ham band (I don't use below 440 MHz).
Thanks,
Yosh
KD6PXE
WPOL560
Yosh,
One point to keep in mind is the effects and how often you get lightning in your area. The plain old stick style antennas appeal to the looks of the installation. They have less wind load and shed ice better. Down side is the don't survive a hit as good as the folded dipole style, with the metal mast.
Down side to the folded dipole style is that they have a higher wind load and fill up with ice more than the stick style antennas. The location around the country has a bearing on the antenna selection.
If your in the Southwest part of the country, where there is a bunch of sand blowing around, that may help make the choice. The fiberglass doesn't fair well to sand blasting. The outer finish is worn off much faster. Then the raw strand that are exposed wick in water. This causes poorer performance when the shell is wet. This condition also causes the shell to degrade faster with time.
Don't buy a cheap stick antenna. The way they are made today, vibration from the wind will self destruct them. As the mast vibrates, the internal connection are stressed and fail over time.
In the old days, they use to fill the center of the shell up with bees wax. Only problem, it got too expensive to do that. The Super Station Master antenns was an excellent choice years ago. Now it is so expensive, only the rich and public safety use them.
Jim
One point to keep in mind is the effects and how often you get lightning in your area. The plain old stick style antennas appeal to the looks of the installation. They have less wind load and shed ice better. Down side is the don't survive a hit as good as the folded dipole style, with the metal mast.
Down side to the folded dipole style is that they have a higher wind load and fill up with ice more than the stick style antennas. The location around the country has a bearing on the antenna selection.
If your in the Southwest part of the country, where there is a bunch of sand blowing around, that may help make the choice. The fiberglass doesn't fair well to sand blasting. The outer finish is worn off much faster. Then the raw strand that are exposed wick in water. This causes poorer performance when the shell is wet. This condition also causes the shell to degrade faster with time.
Don't buy a cheap stick antenna. The way they are made today, vibration from the wind will self destruct them. As the mast vibrates, the internal connection are stressed and fail over time.
In the old days, they use to fill the center of the shell up with bees wax. Only problem, it got too expensive to do that. The Super Station Master antenns was an excellent choice years ago. Now it is so expensive, only the rich and public safety use them.
Jim
A 5 ft mast on top of a 20 ft house? Sounds like you won't be able to support the commercial antennas... too heavy (wind, etc). Yes, a Sinclair 310-C4 folded dipole would be great, but without a sturdy tower or mount, it will end up on the ground one day. Also considering your short run of cable, in my opinion your most practical solution is a ONE PIECE fiberglass stick of sorts with Times LMR-400 feedline. For UHF, runs over 100' will justify the more expensive LD4 or LDF5 cables. Good Luck!
A good ComTelco antenna and LMR600 with Times connectors.
BS450XL4.5C works well and it does not need a tower.
http://www.comtelco.net
BS450XL4.5C works well and it does not need a tower.
http://www.comtelco.net
I agree with April. For my GMRS home repeater (25w Repco... yeah, I know, but it didn't cost me anything), I've had a 50' run of Times LMR600 into a Comtelco BSXL 4.5dB gain stick up at 40' for a few years with pretty decent results. Coverage area's about 5 miles radius portable (4w)/20 miles radius mobile (25w). Cheap (relatively) and it works.
-RF
<font size=-1>[ This Message was edited by: R F Burns on 2002-02-23 15:53 ]</font>
-RF
<font size=-1>[ This Message was edited by: R F Burns on 2002-02-23 15:53 ]</font>
-
Jonathan KC8RYW
- Posts: 1747
- Joined: Fri Dec 28, 2001 4:00 pm
I know of many hams that have been using DavisRF Bury-Flex coax, and have nothing but praise.
"BuryFlex" is a 9914F alternative, with a buriable PE jacket. You don't need expensive LMR-400 connectors, either. Solder on any normal connector you want.
Visit
<a href="http://www.davisrf.com/ham1/coax.htm">h ... oax.htm</a>
for more info.
Again, I know of a lot of hams that swear by this stuff. You might want to look into it.
My two cents.
PS: just because one can bury "BuryFlex", does not mean that one HAS to bury it.
_________________
<IMG SRC="http://141.209.214.215/mpa_radio/tower.gif">Jonathan KC8RYW
<small style="color: springgreen; ">I'm voting Green in 2004! <a href="http://www.takethepledge.com/">www.take ... /a></small>
<font size=-1>[ This Message was edited by: KC8RYW on 2002-02-23 16:02 ]</font>
<font size=-1>[ This Message was edited by: KC8RYW on 2002-02-23 16:10 ]</font>
"BuryFlex" is a 9914F alternative, with a buriable PE jacket. You don't need expensive LMR-400 connectors, either. Solder on any normal connector you want.
Visit
<a href="http://www.davisrf.com/ham1/coax.htm">h ... oax.htm</a>
for more info.
Again, I know of a lot of hams that swear by this stuff. You might want to look into it.
My two cents.
PS: just because one can bury "BuryFlex", does not mean that one HAS to bury it.
_________________
<IMG SRC="http://141.209.214.215/mpa_radio/tower.gif">Jonathan KC8RYW
<small style="color: springgreen; ">I'm voting Green in 2004! <a href="http://www.takethepledge.com/">www.take ... /a></small>
<font size=-1>[ This Message was edited by: KC8RYW on 2002-02-23 16:02 ]</font>
<font size=-1>[ This Message was edited by: KC8RYW on 2002-02-23 16:10 ]</font>
Interesting comments... if one can get a cable free or pay bargain basement prices, then use what you get. If it has to be purchased outright, then cost and performance must be compared.
For the Times LMR series cables, check out http://www.timesmicrowave.com/cgi-bin/calculate to compare loss/frequency vs cable.
For a 50' run of LMR400 at 450 MHz, the loss is 1.4 dB which is 73% efficiency. The same run with LMR600 will yield 0.9 dB and 82%. So it is up to the purchaser to decide if the 0.5 dB difference is worth the extra money for the cable, more expensive connectors, larger thru wall holes, installation hassle, etc.
Most cable vendors have web pages that provide guidance into the best price vs. performance compromise that can be considered in system design. Of course, this may mean nothing to you if you want to run LDF5 for your HF installation. That's in a different league.
<font size=-1>[ This Message was edited by: RFdude on 2002-02-24 00:16 ]</font>
For the Times LMR series cables, check out http://www.timesmicrowave.com/cgi-bin/calculate to compare loss/frequency vs cable.
For a 50' run of LMR400 at 450 MHz, the loss is 1.4 dB which is 73% efficiency. The same run with LMR600 will yield 0.9 dB and 82%. So it is up to the purchaser to decide if the 0.5 dB difference is worth the extra money for the cable, more expensive connectors, larger thru wall holes, installation hassle, etc.
Most cable vendors have web pages that provide guidance into the best price vs. performance compromise that can be considered in system design. Of course, this may mean nothing to you if you want to run LDF5 for your HF installation. That's in a different league.
<font size=-1>[ This Message was edited by: RFdude on 2002-02-24 00:16 ]</font>