Five “MUST-HAVES” To Consider When Buying A Two-Way Radio Repeater

Discussion in 'Amateur Radio News' started by N0REY, Jul 20, 2018.

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  1. N0REY

    N0REY Ham Member QRZ Page

    My name is Ron Kochanowicz. I have been in the repeater and land-mobile radio communications industry for over 20 years. I've built and sold thousands of repeaters that are in service all over the world. So I wrote this guide for you based on my experience.

    There are many two-way radio repeaters on the market and it’s important to pick the right one for your application and budget.
    I've written a brief guide of what I believe are five “MUST-HAVES”
    you should consider as you make your repeater buying decision.
    If you have any serious interest in repeaters, then you need this guide.

    In this guide, you will learn:

    • What to look for in a good receiver -The repeater you purchase MUST have a good receiver

    • How to fully optimize a repeater's transmit power - The goal is to get as much transmit power consistently out of the repeater as possible without destroying the repeater or reducing the repeater’s life

    • Power supplies - Internal or External

    • Controllers - Internal or External

    • What kind of signals should be available on the repeater's accessory port

    Click here to DOWNLOAD your FREE Repeater Guide:


    Hope you enjoy the "5 must-haves" guide.

    All the best,

    Ron Kochanowicz, KCØQVT

    President and Chief Engineer - BridgeCom Systems.
    Repeater infograph for facebook with logo.jpg
    AH2AP, VE5RH, N0TZU and 6 others like this.
  2. K7JEM

    K7JEM Ham Member QRZ Page

    You need someone to proof read the document, then correct the small grammatical errors.

    I would dispute that a built in supply is needed, or even an advantage. Some sites have 12v power available that is already on float chargers. A built in supply is useless in these cases, and if your built in supply goes bad, it might be more of an ordeal to replace it than one that is external. Another thing to point out is that a repeater needs to be synthesized in today's world. The MastrII and Micors are good repeaters, but it is extremely difficult to get crystals to move them to new frequencies.

    Another thing is to have a repeater with a good service manual and schematics, so anyone can troubleshoot and work on it.
    Last edited: Jul 22, 2018
    NL7W likes this.
  3. WB2JIX

    WB2JIX Ham Member QRZ Page

    K7JEM, AND leave that manual at the repeater so people can find it! Whoever removes it and doesn't return it, gets a good whipping.

    KA5RIO and WG8Z like this.
  4. W5TXR

    W5TXR XML Subscriber QRZ Page

    As a retired Motorola guy of 25+ years I have an opinion on this.
    I’ve installed a repeater or two....
    First off the controller has nothing to do with the receiver/ transmit bandwidth, this is a function of the receiver and exciter.
    In addition I strongly recommend a RF isolator on the transmitter. Even if intermod isn’t an issue, it protects the PA from a sudden antenna system failure, because the PA always sees a perfect 50 ohm impedance no matter How the antenna system is performing.
    Duplexers should be BP/BR as in TX/RX Bird duplexers.
    Just plain Band-pass isn’t really that good.
    A quality surge/lightning protector on the antenna line like the Polyphasor brand.
    Always try to use at least 7/8” heliax
    RF jumpers should be RG-142 quad shield cable, jumpers to the polyphasor, duplexers. It should be kept short because it’s lossy but quad shielded. Getting the repeater antenna as high as possible and or the highest gain antenna isn’t always the best choice.
    Antenna combiners and receiver multicouplers should be avoided if possible! This method is extremely inefficient, there is a tremendous amount of wasted RF power.
    It is Only used in situations where antenna space/weight is extremely limited.
    Using a accurate RF propagation plot as part of a system design tool is evermore important especially in areas where frequencies are congested. There are companies that Will do this for a reasonable price it is money well spent.
    Motorola publishes a site standard for everything from ventilation to proper bonding. It is called “Motorola R56 standards” this is a must for site owners. It is a wealth of information!
    There is so much more in repeater system configuration.
    Once the system is installed an effective sensitivity test must be performed along with a repeat sensitivity test.
    The effective sensitivity test is the only true test on how well a antenna system is working with the equipment connected.
    It can Also be an indicator of other antenna system problems.
    If you are unsure of what this test is or how it is done please feel free to IM me.
    W4END, W5BT, WJ2L and 4 others like this.
  5. K7JEM

    K7JEM Ham Member QRZ Page

    Duplexers need to be selected on a case by case basis. Some applications will use BP/BR, some may use pass only. Some may use a combination of both types. And others may need reject only duplexers. One size doesn't fit all.

    RG-142 is double shielded, by definition. Not quad shielded.

    This really isn't true. RX multicouplers can provide a much better RX signal to all in band RX's in the building, when designed correctly. And TX combiners don't have to be especially lossy. In today's tower environment, the fewer antennas on the tower the more cost effective it can be. You don't have to sacrifice performance when using an RX multicoupler or TX combiner. We use them a lot on several sites around here. At one point in the past, we had 18 UHF RX's multicoupled onto a single RX only antenna. Saves on duplexers, feedlines, and antennas.
    NL7W likes this.
  6. W5TXR

    W5TXR XML Subscriber QRZ Page

    I completely disagree.
    The receiver multicoupler by itself is fine, antenna combiners are very lossy even when installed and designed correctly.
    I’ve been to numerous Motorola schools and worked with large public safety systems. This practice is avoided when possible.
    I’ve seen several LTR systems that used the combiner system where 100 watts out of 5he PA and 1-3 watts out of the combiner matrix.
    I can show you documentation from Motorola on this practice.
    It’s all about experience and training.
    I expected at least one comment that would disagree with me.
    That’s the nature of the forum. It is what it is.

    M.A. Lacy
    W5BT and NL7W like this.
  7. W5TXR

    W5TXR XML Subscriber QRZ Page

    Correction, RG-142 is double shielded. I was discussing a quad band mobile with someone when typing, got distracted.
    So, correct 142 isn’t quad shield
  8. K7JEM

    K7JEM Ham Member QRZ Page

    I don't disagree that there CAN be losses, I am saying that there are not ALWAYS excessive losses. Your comment about them being "extremely inefficient" is not always true. Sometimes it is, sometimes it is not. You have to look at each instance, and what it is trying to accomplish. You can't condemn an accepted practice, when there are many cases that make it the best way to go. A TX combiner could have less than a dB of insertion loss, if it is only combining 2 transmitters that are not close in frequency. Even a 4 TX combiner might only have slightly more than that, if the frequencies are far enough apart. The hybrid/ferrite type are quite lossy, but even they have applications.
    NL7W likes this.
  9. W5TXR

    W5TXR XML Subscriber QRZ Page

    A built in power supply might be a good thing, it should be done on a case by case basis. One size doesn’t fit all.
    My Yaesu DR-1X repeaters work great on the internal power supplies with the B/U DS back-up battery
    Moving on........
    N3HQN likes this.
  10. W5TXR

    W5TXR XML Subscriber QRZ Page

    To each his own!
    K7JEM likes this.

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