repeater setup, good antenna needed.

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vzfarms

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Hey guys im sure this question comes up alot.
Im putting up a commercial repeater set up for my business use. Im using an icom fr-3000 repeater, celwave duplexer, and I need to find a good antenna to use. My coax run is 140ft and cannot be shortened. I have some belden rg-8 that I planned on using and an antenex FG1523, but my radio tech says that I will have alot of loss with this. Can anybody suggest a place to get a good high quality antenna for the cheapest price? Or, alternatively, should I just use the coax that I allready have, and the antenna, and see how it works. PS it is a vhf setup in the 153.xxx range on the repeater transmit side.
 

FLRAILMAN

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repeater set-up, good antenna needed

I'm surprised that your radio tech hasn't guided you all the way in your repeater set-up process. Most of the commercial & public safety communications systems I've seen in the New York Metro area utilized either LMR-400, heliax or in some extreme cases, hardline cable to feed their antennas, usually depending on the needs required by the type of environment they were placed in. As for the best antenna, there are just too many variables to properly reccomend an antenna without having additional information to go on. Don't despair though, you will get many more topic related replies soon enough.

www.wpsantennas.com/timesmicrowavelmr-400.aspx

www.rfparts.com/heliaxcoax.html

DF Countryman - Coax-Hardline-T10


FLRAILMAN
 
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fineshot1

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The LMR400 is not appropriate for full duplex repeater usage - go with the 1/2 inch hardline or similar.

As for antenna you would do well with a vhf Station Master or similar type stick.

Normally I would recomend a vhf 4 bay dipole array but they get mounted on a 20 foot
or so mast and can be a bear to properly mount.
 

vzfarms

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Ok let me clear this up he has given me lots of ideas. He does not want to sell me a cheap antenna, for obvious reasons, because he does not want to sell an inferior product, and I do not have $800 to spend on an antenna and another $300 for coax. I asked for some input on what you guys have used and if the cheap hi gain antennas out there are any good.
 

N0YFE

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Best you can purchase

With your budget, I would be honest with your radio technician as to what you can afford and start with LMR 400 cable and the best antenna you can purchase at this time.
 

FLRAILMAN

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Repeater set-up, good antenna needed

My friend, you are there & we are not. NOYFE, kb2vxa, fineshot1 & I are trying to assist you in the best possible way with the information you gave us. I'm quite sure that they will concur with me that your radio tech may either be incompetent and/or may not have your best interest at heart. Correct me if I'm wrong but is this guy a friend of yours or is he giving you some type of shoestring budget personal deal? because if that's the case, I can understand your dilemma however if this is strictly a business transaction then I would strongly suggest that you find a reputable dealer, tech or whatever he is, Please don't take offense as you are family & we want to offer you the best advice to enable you to accomplish your goal. Keep us posted.

FLRAILMAN
 

vzfarms

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look im not asking for you to critique my dealer, if I wanted to spend alot more money than I allready have on the repeater and duplexer alone, I would buy the antenna and coax that he would love to sell me. He says my rg8 will work and my 3db gain antenna will work, but he ran the numbers through the computer and gave me my ERP with both setups. He knows nothing about the cheap Tram 6.7db gain antennas available for about $90 or others like them.. Therefore he cannot offer his advice on them. He has not been bashing them, just said he didnt want to tell me anything about something he has never experienced. Thats why I turned here.
 

FLRAILMAN

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repeater set-up antenna needed

fineshot1 states that LMR400 is not an appropriate option for a full duplex repeater set-up & it's far superior to your techs suggested RG8 coax & we are just still on the coax debate, so here is your dilemma, whos advice do you believe, as I earlier stated, you are family & we only want what's best for you, so easy does it. I have nothing more to contribute so I'm out of here, the rest of the membership can assist you from here, good luck.

FLRAILMA
 

Josh

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My input:

You get what you pay for. For a repeater you want to use the best stuff, otherwise the performance is going to falter.

You will want to use Heliax, not LMR and not RG8 or Belden 9913 as these are all inferior and not recommended for repeater use, especially at 140'.

For an antenna, again $800 isn't all that uncommon for a decent antenna. You may strike gold finding a used one somewhere though. There's a "for sale" gas station a couple miles from me with a 20' tall Motorola stationmaster strapped to the roof. Perhaps a phone call to the real estate agent about "removing that eyesore" could prove fruitful. The TRAM antenna may work, for a short amount of time, but having exposed elements and numerous water intrusion points it will not work for long, but for $90 you could justify replacing it, but eventually the costs add up.
 

vzfarms

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Yes i have been trying to find a used antenna with no results. I will continue my search for some hardline and an antenna thanks
 

fineshot1

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Yes i have been trying to find a used antenna with no results. I will continue my search for some hardline and an antenna thanks
Keep trying to find a great quality antenna - sooner or later one will turn up.

I understand your dilema on the $ being spent but unfortunately cheap and hi performance rarely go together.
 

fineshot1

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Yes i have been trying to find a used antenna with no results. I will continue my search for some hardline and an antenna thanks
For hardline cable you may want to try Ridge Equipment - do a google search and you will find the
web site. Sorry ,I would supply you with the link but the work IT dept has that blocked from me.

They sometimes have good deals on hardline and are great to deal with. Look for LDF4-50A(1/2") or
LDF5-50A(7/8") hardline cable - both are great choices but the LDF4 will most likely be cheaper
unless they are eager to sell the LDF5. You will also need connectors for each end and they may
be able to supply them as well.

If I get the time I will try and find suitable antennas for you to look over.
 

kc2rgw

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It is _all_about_the_antenna , you can use some really cheap radios if you have good antenna and feed line, followed by a good duplexer.

Decibel Systems' folded dipole arrays or a Stationmaster are worth the money and unfortunately so is hard line.

Been round and round with this recently. Started with home use fiberglass antennas, they actually were o.k. if tuned carefully, but going from 9913 and LMR400 to 1 7/8" hard line was night and day. Replumbing the whole rack with carefully done fresh connections made another major difference. Adding a Stationmaster after all of this and a GAsFET on RX...now we're talking....and listening.

This was all done on amateur 440 and we got lucky with a lot of existing line, space and antennas donated. We were running 100W or so out of the duplexer with lousy line and antenna and now at 20W out of the repeater, the signal is better than it was with 100W before.

Small things will ruin a UHF machine.
 

lmrtek

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LMR-400 or equiv is fine at VHF freqs

If you are going to mount an antenna on TOP of a tower, stay away from fiberglass colinear antennas.
The are prone to internal fatigue failures from moving around in the wind and the will be easily destroyed by even a small lightning discharge.
Dipoles are the only way to go for top of tower installs.
Andrew makes some of the best.
Sinclair also makes a fine product
Your repeater system is only as good as the antenna, so tht's where you want to spend all the money.
A 4 diplole array like a Andrew DB-224 will outperform anything else available and will last 30 years.
 

kb2vxa

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I'll go back and remind you of your tech's competency. If he were doing his job you would not be doing it for him and that's just the way it is in business. Do YOUR job, give him a budget and let him work with it but be ready for compromise, I'm pretty sure it'll cost a bit more than what you have in mind. Consider your tax accountant and ask what may be counted as "the cost of doing business" to put it in broad terms, he can fill you in on the details.

Inexperience in this sort of thing is no excuse when he has a telephone and computer at his fingertips, if I can learn on the fly why can't he? Let him do his homework and networking, that's his business, so why is the boss not minding his own business so to speak?

Before you do anything put one thing firmly in front of your mind; taking the cheap and dirty way out will only be dirty in the end. Fixing a cheapo will cost you more over time than doing it right in the first place. To put it another way... penny wise and dollar foolish is a phrase worth remembering.
 

fineshot1

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That's kind of a wierd site to enter, anyway here you go fineshot1:

www.ridgeequipment.com

FLRAILMAN
Thanks - yes there are a bunch of odd sites and I have been pretty frustrated with some of them
due to they way they provide info(or not providing info - hence the frustration).

Anyway - see below for some info I was able to copy into this thread and guess you will have
to review it with your radio tech and make some decisions based on whats best for you and
your finances - good luck vzfarms and let us know how you make out.

PS - MOTEX has some good points - see his post.

Lots of antenna info on the repeater builder web site - see below

Antenna Systems Information from www.repeater-builder.com

Maxrad MFB1503 - Probably a decent cheaper antenna- see link below

PCTEL, Inc. VHF White MAXRAD Fiberglass Base Station(MFB) Omnidirectional Antennas Non Cellular Omnidirectional Base Station Antennas

Super Station Master - see link below

RFS

The Kathrein K55162n1 series - see below

http://www.kathrein-scala.com/catalog/K5516211.pdf
 

vzfarms

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first of all, thanks for the input
I think what im going to do is go ahead and shell out the money for 1/2" andrew heliax hardline. I will use the base antenna that I allready have and continue my search for an antenna. A discount warehouse near me has new Stationmaster PD10017's for dirt cheap!!! those are 890-915Mhz and 925-960Mhz 10db gain antennas, no good for me but still one hell of a deal for someone. Hopefully someday they will get some in the VHF range in, that would be nice...
 

mrweather

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LMR-400 is not appropriate for full-duplex repeater operation. The mismatched metal used for the shield (copper and aluminum) will introduce all kinds of noise down the road.

Make sure to use cable with the best possible shielding. You want absolutely no RF ingress on the receiver except from the antenna. You might be able to get away with RG214 for the interconnect cables but for a run that long to the antenna you need Heliax.
 
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