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Author Topic: Need to find the BEST antenna I can for our repeater  (Read 18082 times)

NF9L

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Need to find the BEST antenna I can for our repeater
« on: September 15, 2011, 04:23:37 PM »

Putting a UHF 440 repeater on a 15 story hospital and we have everything but the antenna. I have noticed DB420 antennas are used on allot of repeaters. I consullted with a company that sells most brands. Here in a few sentences you can see their thoughts and preferences:

Celwave is the #1 Pro Repeater Antenna in the US at least a 5 to one margin over all the others.
We see this with our own sales of Celwave vs Db vs Comprod vs Sinclair vs TeleWave etc.
Db are now made in Mexico and the warehouse is in Texas. Celwave is USA built.
If you want to go cheap look at our Comtelco line -- but I can tell you they do not sell as well as the Celwave or even the DB.
My Favorite is the Comprod -- They are the very best of all.  But they cost over $1,300 and come from Canada.

Forgot to mention no ham freqs for DB any more they just do not make the cut for the 440to450MHz any more period -- So you have to put up the 450MHz antenna and put up with 1.5-1.7 to one SWR - theyre are some tricks with the loop and the harnes you can do to help lower you can find these tricks on line posted by hams who got free commercial antennas and converted them to ham. BTW it was when CommScope bought the Andrew company they decided to quit making the ham cuts any more.


So that all the information we got on antennas and still don't know what to buy. Was hoping to get feedback here to help with our decision . . . thanks
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AD4U

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RE: Need to find the BEST antenna I can for our repeater
« Reply #1 on: September 16, 2011, 03:42:56 PM »

Celwave makes at least two different 440 MHz station master type antennas.  One gives a true 5dB "gain" and the other one gives a true 9dB "gain".  Every antenna has its weak points but I agree the station master antennas are among the best for repeater applications.  I own 3 repeaters and I use station master antennas.  One has been up over 20 years with no problems.

Dick  AD4U
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K1CJS

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RE: Need to find the BEST antenna I can for our repeater
« Reply #2 on: September 18, 2011, 09:18:08 PM »

If your budget demands concessions, try looking at the Hustler G6 for 440 mhz.  Excellent gain, and quite a lot of people swear by them for repeater useage.  The other nice thing about them is that they can be fairly accurately tuned by measurement and adjustment of the antenna sections.  I believe that they're even equipped with N connectors.
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K4JJL

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RE: Need to find the BEST antenna I can for our repeater
« Reply #3 on: September 19, 2011, 06:50:35 AM »

I've been using DB420s for years.  They're great antennas.  Pretty durable and you can't beat the 9dbd gain.  The 450-470 split will work just fine on the ham bands.  With 100w forward, I only had 2-3w reflected.

You can find them at hamfests anywhere from $100-$500 depending on shape (and seller's knowledge).
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N5NPO

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RE: Need to find the BEST antenna I can for our repeater
« Reply #4 on: September 19, 2011, 04:28:26 PM »

If you think lightening may be a problem for you, then I cannot think of a better antenna than the DB-420 or even a DB-408.
If you don't have a lot of lightening, then Telewave makes some exellent fiberglass antennas. Their 6dbd works really well. It is about 6 ft tall. Their 10db 20' tall antennas work really well too, but we have lost two of them to lightening and one to bad wind and weather. If you put one on the side of a tower with a a stand off bracket and a top brace, you will probably have no trouble with it.
Andrew (DB products/Commscope) also has a 20' tall fiberglass antenna that works well. Treat it like the 20' Telewave...
Just my $0.02.
73
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K6AER

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RE: Need to find the BEST antenna I can for our repeater
« Reply #5 on: September 22, 2011, 05:09:43 PM »

Before you pick an antenna, regardless of manufacture, you need to fill in some blanks;

How far do you need to cover in miles?
Is the pattern omni in coverage?
Will you need down tilt?
Is the hospital on a hill or elevated from the coverage area.
What is the wind Sq. Ft. Loading the mount can stand?
How long is the antenna expected to last?
and...........
What is your budget?

Other questions abound.

Have you done an intermod study?
Is foot traffic a problem for RF safety?
Coax connector needed?
What level of filters are needed for operation in a high RF field? (other radios)
Where is it going to be mounted? Will a professional tower rigger be needed?
Grounding??????

As you can see there is more than just buying any old antenna.



« Last Edit: September 23, 2011, 10:43:58 AM by K6AER »
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