America - Repeater Components

This is not a tutorial on how to setup a repeater or how to perform maintenance of a repeater, just a rough outline for those that are considering erecting an amateur radio repeater with an output not to exceed 50 watts out of the duplexer, not a low power GMRS repeater.

1. Repeaters come in all types and sizes, FM, Digital, combination FM & Digital, automatic mode switching, support for WIRES-X, and output power ratings, typically adjustable between 25 to 50 watts. Prices can reach close to $2,000, some manufacturers offer special program pricing deals like Yaesu.

2. Duplexers are another costly investment. New high isolation 6 cavity 8" duplexers can cost you up to $1,500 - $2000, or more, some used can be found between $750 - $1000 on places like eBay. Don't waste your money on Chinese notch duplexers, first their junk, secondally they won't handle the isolation you'll need.

If your purchasing a used duplexer, it will have to be tuned by a qualified radio shop or someone with expertise in tuning filters or duplexers. The duplexer needs to be tuned using a spectrum analyzer and variable network analyzer (VNA). Generally the charge for duplexer tuning runs around $85.00. If you purchase a used duplexer make sure it hasn't come out of an installion that was hit by lightning, it's probably carbon tracked and junk. Sometimes someone in a club has this sort of equipment and they can perform the task.

3. Repeater Amplifiers. New reliable commerical grade 100 watt amplifiers like Henry amplifiers VHF or UHF typically cost just under $1,000. They can be ordered with a preset drive input of 1 - 5 watts. Obvioulsy the purpose of the amplifier is not necessarily to have the biggest signal in the county, the purpose is to take the load off the repeater (known as the exciter) and eliminate equipment wear and tare. A repeater has to hear as good as it talks, there has to be a balance between transmit and receive.

4. Coax (Feedline): The cheapest recommened coax would be RG214/U milspec douple silver plated shields and silver plated center conductor. RG214/U generally starts out at about $3.50 a foot. The best would be something like Andrew Commscope AVA5P-50-C, 7/8" HELIAX® Andrew Virtual Air Coaxial Cable, very costly, 100 feet can cost around $300 - $325, you have to shop around various coax cable suppliers. This does not include connectors. Silver plated N-Connectors shoud be used at a minimum.

5. The Repeater Antenna: Quality repeater antennas can get expensive. One budget repeater antenna is the Hustler G7 (VHF) or G6 (70cm), they can cost you over $200 each, if you can afford commerical grade then folded dipole antennas are the way to go, 4 bay up to 8 bay, however they can go as high as $3,000. I've used Hustler antennas for years, the less expensive choice with excellent results, however, the G7 VHF has a way of attracting lightning, over 44 years I've had the top section blow off after a lighning strike.

6. The Z-Matcher: allows the transmitter to operate at a maximum efficiency by matching the source impedance transmitter output impedance (repeater/amplifier) to the load impedance (antenna, duplexer, isolator, etc.).

7. The Repeater SWR Bridge/Wattmeter: Don't cheat on this one, you'll need a good wattmeter like a BIRD or Coaxial Dynamics, cost can vary between $350 - $450, you want accurate results. If you can afford it, a Rig Expert AA-650 Zoom antenna analyzer is highly recommended, but they cost around $700. Don't rely on an MFJ SWR/Watt meter.

8. Tower Site & Location:

You'll need to put up a tower for the repeater, this is quite an expense. Quality tower sections like Rohn 25G or 45G are costly, a 10 foot section of 25G costs approximately $175.00, 10 foot sections of 45G can cost up to $414.00 per section, so 100 feet of 25G would cost $1,750.00 without S&H. You''ll need to purchase a certified tower base plate and grounding materials.

You will need to purchase certified I-bolts, certified turn buckles, and a multitude of other hardware to support the tower, and guying posts this can reach substantial cost. Next you'll neded to pour concrete footings for the tower and guying posts. In all, raising a tower can cost $3,500.00 - $5,000.00, depending on the quality of the installtion. The entire cost of setup a repeater (new) can reach $10,000.00.

Note: I would not recommend using used tower or used tower supporting hardware, (dangerous choice), remember, you need to have all this insured because of libility issues, you or your club are responsible for any damages should your tower collapse and damage another's property or cause harm to others.

You will need a tower site, if the tower is not on your personal propery then you or the club will incur the monthly expenditures of rent for the site and expenses for power, phone, and possibly Internet service depending on the features you intend to provide for the repeater.

This gives you an idea of the cost to raise a repeater and is a costly investment, generally a radio club with the necessary financial resources will take on this expense, individually it can be a lot of out of pocket cash to invest if your doing it on your own, I've been there and done that. Using cheap componets will cost you nothing but aggervation, I won't outline all the problemactic issues that can arise with cheap components, bottom line, all you'll be accomplishing by cutting corners is a crappy repeater installation and a lot of wasted money and time, not to mention you could be sued.

Bob Krueger, AB7CQ

Web Administrator

RPTR 1: 146.920/146.320 PL 123.0 (WIRES-X Room 28187)

RPTR 2: 444.600 / 449.600 PL 100 (LAN Linked)

Simplex IRLP Node: 7515 PL114.8 (146.540)

Email: ab7cqradio@ebidpal.com

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