Batboard

Hi, I am setting up a GMRS repeater, and I am looking for different opinions on what kind of antenna I should purchase.

Vertical Omni, Dipole Array ( i think thats what it's called, and lastly yagi(S)

Also, maybe each has it's specific purpose, so if anyone can enlighten me as to which I might get the best performance with it would be greatly appreciated.

Thanks

You will get more gain/performance out of a dipole array, although it costs more. The dipole also offers better lighting protection to the equipment.

The omni will work just fine, but the dipole will almost always give better range and reception.

Don't use the Yagi unless the repeater is on one end of town from where your mobile units will be. These are directional antennas and really aren't intended to be used for repeaters (most of the time).

Make sure you use a good RF cable, connectors and duplexer- don't be cheap on these!

my 2 cents

Hi:

Antennax makes a good line of inexpensive
antennas I use all the time. A good 5 to 7
DB Gain Vertical runs anywhere from 185.00 to
345.00 plus about 30.00 for brackets.

Email me direct if you are interested as
I have them in stock all the time.

Photo upon request.

MS

I have to disagree with the post that jim provided. He said that the dipole style antenna works better than an omni. He didn't elaborate any on that answer.

An antenna provides for the reception and transmision point of your communications system. The omni sticks for lack of a better way to describe them, come in a choice of gains. They are available with electrical down tilt for use on high locations. These locations might be a tall building, or a mountain top. They are generaly lighter than the dipole style antenna. The sticks have less wind loading than the dipoles. They tend to shed or not collect ice as fast as the dipoles.

Sticks have a weathering problem over time. The outer surface will loose the finish and start to wick water as time goes on. This causes system performance to go down in wet weather. The real down side is they don't stand up to lightning as good as the dipoles.

On the flip side, dipoles don't have electrical down tilt. Dipoles have a higher wind load. Dipoles have more exposed cables to weather. More RF connections to go bad and leak water into the cables. Dipoles collect ice much faster than the sticks. You can swing the dipole elements and change the pattern of the dipole antenna.

If your in an area where you have allot of sand blowing all the time, then maybe the stick is not the right choice. The sand wears off the finish of the sticks. This then allows water to start to penetrate the support. This will cause several problems. When wet, it will cause a lower signal in both directions, RX and TX. In a cold climate, the moisture will speed up the failure of the outer surface.

Up in New England the sticks would last maybe 5 years. This was if the newer antenna construction didn't fail internally with the electrical connections from vibration. The old style constuction of the sticks would have bees wax poured into the hollow space inside the fiberglass support tube. Electrically they would last forever. Most of the new ones are not made this way. Have seen several fail in less than a year. The elements inside the antenna support just vibrate back and forth due to the wind. This causes the solder connections to fail.

Hope this is an insight on the good and bad of your antenna choices. I have tried to take the middle and not side one antenna over the other. That almost has to be done on a case by case use.

Jim

For sheer performance/gain, the 4-bay folded dipole will outperform just about any omni...if properly set up.

Folded exposed dipole is first choice.
And as a second choice, the ComTelco BSXL series are real good performers. They have real tubular copper elements inside the fiberglass, not a peice of 14 gague wire with a curly que like Maxrad and Antenex do.

http://www.comtelco.net

Thanks for all the info guys.

I will be checking out the Comtelco website and maybe you guys have some links of certain "preferred" antennas that you can send me.

I will also be looking into possibly linking two systems and will place s seperate post for that issue.

Thanks again

For linking the systems, check out Will's extender/link module, plug and play on most radios and it works extreamly well.

Hi April, Thanks, and I will be contacting Will once I have both radios ready andthe duplexer tuned.
I was more looking to link two seperate sites, and I am quite familliar with basic repeater operation, but not however with linking two sites, maybe 900 meg maxtrac type links, etc.
I don't know the basics however on how the systems would tie in.

try a 22ft super station master,you wont be disappointed.

Radio Guy 31, Do you have by any chance a website or a link where I can check specs and possibly a picture of this antenna.

Thanks very much.

A bit pricey for an individual to lay out.

Hi:

These UHF Omni's that I use all the time
are the 5 foot and 7 foot models.

UG-4607 ( 7 DB Gain )
FG-4605 ( 5 DB Gain )
A little expensive to ship UPS, but they
still are very good antennas 30-40.00 as
they sometimes class the 7 DB gain antenna
as oversize, but it still can be ship by
UPS.

<img src="http://www2.4dcomm.com/metrotech/antenex.jpg">

PS: The Photo shows just ( 1 ) Bracket
being used ( Dumb ) The Bracket Kit
has ( 2 ) Support Brackets supplied.

<font size=-1>[ This Message was edited by: [email protected] on 2002-03-14 15:03 ]</font>

Mr. Monte,
Have you ever taken a Antenex FG series antenna apart? They have just a 14 gague wire with a few soldered on sleves to "patch" in some coils. They look like mobile whips in a fiberglass tube!!!!

They do NOT work well on Duplex repeater setups in the 460mhz band FROM MY EXPERIANCE(so Nand will not try to kik my a*%).
The ComTelco are the same price range.

Hey, Nand, I like the BIG Sinclair UHF folded dipole with 5 degrees down tilt at a tilt of $900 each.....

Hi:

YES ! I have had a occasion to examine
the Interior of the Antenex ( and others ) , and its the SAME DESIGN as used in some later
version SUPER STATION MASTERS being used today !

I was caught a little off guard, as I too once
prefered the " COPPER TUBBING" over the Copper Coils, however was informed the industry change their view points due to the Extra Weight, and flexing problems with 18- 26 FOOT antennas.

In poor weather conditions, the Pipe design
tended to fail in and around where the couplings were made ( Due to Flexing ) Hence the Coiled Copper wiring evolved. ( So they say )

I have a whole grave yard full of Super Station Masters I fix every once and a while
when time permits all having broken solder
joints around the tubbing witch caused them
to fail.

With respects to Antenex not working on Duplexers, I have used more than 50 of them,
and to date, not one has encountered a problem, however, we do pay close attention
to the proper installation of all the Cables
and Connectors.

I can offer to you, they due have SPECIFIC
Freq Ranges, and if you try and used a Commercial range 460-470 Mhz Antenex on
440-450, YES you may have problems due
to reflected Power

We have these Antennas on 10,000 foot Mountains to Garages....But I still like
the Old Super Station Master Antennas where enviroments sre real tough. ( Hence
the reason I buy Old Ones ), but when we install them, we have additional supports
at the top to keep them from Flexing...That
is the main problem with the older antennas
that use Copper Tubbing"

A bit of a Over Kill to install a 26 Foot
Super Station Master on a Parking Lot Gate
House.

Hope the clarification helps.

The nice thing I like about the Antenex Antennas is they are Light Weight, Easy
to Install, last for years, and well they
so far have never failed in a Repeater or
Base application to date.( and pretty inexpensive ) I hate the word Cheap !

And for some reason, they have not been struck by Capillary Lightning and my Super Station Master has been hit ( more than once ) in the same general location.

They of course will not survive a Direct
Hit !

http://www.antenex.com/main.htm

Not to say other manufactures are good
or bad....Just depends on what menu you
like to view.

One final thought: Antennas are should be
chosen with respects to loaction, terrain,
height above average groud level, and of course how much funds are availible. Cmommerical Grade Antennas will always
outperform Consumer types, and if you are
looking for the " BEST" and can afford it,DB
Products, Celwave make some of the best Base/Repeater Antennas and they have a price
that reflects the performance.

If you can afford the Price, DB-413's, Super
Station Masters will out perform the lower
tier antennas, but most those antennas are in
the 500.00 to 1000.00 Price Class, and one
will need to spend additional costs on good
1/2 to 7/8" ( prefered ) transmission line.

I had to say that, as I have seen some use 100' of RG-8 Cable feeding a DB-413 and was
complaining the system was not working well.


Monty





<font size=-1>[ This Message was edited by: [email protected] on 2002-03-14 13:50 ]</font>

We had used the Antenex 7db antennas for a while on a few 300 foot buildings with average wind conditions and had 3 of them break apart where the fiberglass meets the metal shaft. I don't know if it was a defective run or what but Tessco took them back. They all failed in less than a years time! This goes back about 2 years ago. Bill

Hi Bill:

Please let us in one "What" antennas
they replaced them with? Or did they
just send you a couple of replacements.

Also, you might inform us as to what
area of the US you are in....

All helps to let us all know the
parameters of what happened. Strange
I have never run into that sort of problem.
but as I mentioned, when we install any
Base / Repeater Antenna System, we pretty much go all out to insure everthing is installed properly....

That means Proper Transmission Line, Dual
Support brackets, Cable support boots, Coax
hangers, and of course a sound mounting support structure.

One reason I have installed so many of the
Antenex Antennas were replacing other horribly installed antenna systems, and we found everything from Duck Tape to bailing wire being used to support them.

We replaced a Super Station Master Failure due to the person trying to use Duck Tape to wrap a 24" Station Master Support to a 2-1/2 metal pipe. That alowed so much Flexing, it broke in 3 pieces..So much for the life of
a 900.00 antenna

Guess they did not want to spend the 100.00
for the support clamps.

MS

Damn, Monte is right again.
I liked the super station master when they used coax cable elements, did not have too much flexing problems. The station masters were designed to flex to shed the ice.
BUT had a UHF 10db 24 foot "wet noodel" receiver antenna on top of a 130 foot tower on a six thousand foot mountain-top and every time the wind blew, the signal went away! Put a Sinclair four folded dipole in it's place with down tilt--no more problems.

The medium gain antennas with the fiberglass tube (one diamiter) do real well, and to reply on the Antenex's breaking at the base/fiberglass joint, that is very common. The ComTelco has the fiberglass "pipe" housing is thicker and goes all the way into the metal mounting sleave base down to the connector.I like this much better. So Nand does not get on my case (again), these are from my thirty five plus years experiance. That is why the nicknamed me "Will from the hill", I was usally on one mountain-top or another fixing repeaters and remote base stations or microwave stuff.

<b>Hi Will:

I am VERY INTERESTED in this " Flaw "
Failure of the Antenex Shaft tube to
the Metal Support issue being reported
by you and a few others.

I would be more than willing to PAY you for
your time and effort including shipping so
I could either see the Cracks, or see one
even broken from a installation.

The Newer the better, but will take OLD ones
too

Only looking for the metal Support to the
Shaft, so a Cut Off would be OK.

I have a Shipping Tube I can send if you have
not tossed them into the dumpster.

Monty

Hi Monty, I first have to say that I only have a fraction of the experience that you fellows have. I found 2 invoices from Tessco. I returned the bad ones for replacements to use only at low locations such on a house. The invoices I have show one of the replacements (FG4607)sent in May of 1998 and the other in Aug 2000(radomes cracked). We substituted (used) PD201s and haven't had any problems with them breaking. I am in NY and the weather was not severe at these locations. We used a pair of celwave PD46 type brackets with piping. Bill

The PD201, five db gain is the standard of the industry. But cost way more.

Monte, I will bring that broken antenex antenna by on thursday afternoon.

HI, I have decided to go with one of the two following model Comtelco Antennas, as I have quite a high structure to affix the antenna to and I don't believe that I need a Super Station Master or anything that advanced.

Please leave me your opinions (if any) on the two following models and also if someone could tell me which mount, part #, etc I could use to mount to a mast, as the website does not have pictures of the mounts.

http://comtelco.net/cgi-bin/w3-msql/cc- ... m=BS450SNC

http://comtelco.net/cgi-bin/w3-msql/cc- ... 50XL4.5BCD

The BS450S series are considered light duty and include the mounting U bolts fo a 1 1/2" mast.

The BS450U is the heavy duty one I use a lot of. It is unity gain, and the mounting clamp set is BSMNT2 and is two aluminum brackets and stainless steal clamp bolts for the HD instalations. Also for the BS XL series.

The BS450XL series have gains of 4.5 db or about a little over two times power with reduced vertical beamwidth,30 degrees vs 75 degrees on the BS450U. They "squeze" the radiation pattern to get gain.
The BS450XL6 is 6 db gain or four times power! 20 degrees, but is much longer at 96" (like a CB whip!). If you have high wind conditions use the 4.5 so you do not get the wind blowing the antenna beam away from the coverage area..

HI, Based upon some of the replies I have received, I think I may end up going with the Antennex 5db gain style antenna, model #
FG4505W, and for the additional charge of $25.00 they will tune to my freq.

I have 2 questions, 1) Is this a good antenna to choose for GMRS use, and 2), Since it will be a UHF repeater operating, and not a simplex base station, what should the antenna be tuned to, between the two operating freqs, the repeater TX freq, or the repeater RX freq?
Lastly, What are good grounding options, ground rod sizes, wire guage, bare, or covered wire, and inline arrestors, etc...

Thanks everyone for the great help so far.
Thanks

Chef, save yourself a lot of greef, get the BS450XL4.5C 450 to 470 Comtelco antenna. A much better antenna for the same price and you DO NOT have to have it "tuned". $ 82.50

I just put up a RFS Super station master up on my freindsa roof for VHF i have not had a chance to hook the radio up (need to moun the cabinet on the house)

HI:

As Antennas have always been a target
of mass discussion, be assured all these
antennas are really pretty good performers.

If you have a favorate dealer you trust, always keep in mind 1/2 of what you get is
who you get it from, and the support from
them.

As far as " Tunning" is concerned...Thats
really unecessary.....Your Receieve Freq is
going to be 5 Mhz away from your Tramsmitt Freq. Hence logic should tell you to chose a
antenna within your range....460-470 Mhz or
450-460 Mhz is perfectly OK....

What is really important is the transmission
line and how well you do the installation.

Better the installation, better the performace.

Monty

Monte, I have the broken FG4505 and will drop it by tomarrow (thurs) afternoon.