Repeater setting up

[Tangobravo]

Hi all I am building a simulcast VHF LMR network at four remote locations using
four Kenwood TKR 750 repeater. I am using three ICOM CS-F521 radios as RF link, both
repeater and RF link radio is connected via OPC-617/DB9 to DB25 cable. I can TX but
no RX, so far the configuration seems to be ok but I not am sure if I left out any
area in the configuration.
I will appreciate all the help from you guys in resolving this problem .

 

[WA0CBW]

What are you using for the simulcast voter/distribution amplifier?
BB

 

[Tangobravo]

What are you using for the simulcast voter/distribution amplifier?
BB

I am trying to link the radios without voter/distribution amplifier Is that possible?

 

[WA0CBW]

?? I'm not sure what you are trying to do. Do you have one receive site and multiple transmit sites? If you have multiple receive sites you will need to "vote" one site's audio and then send that audio out to all the transmit sites in synchronization with each other. If each site is a repeater then your RF links need to be duplex as well. Maybe you can describe a little more of what you are trying to do?
BB

 

[Tangobravo]

WA0CBW,
This is how the network setup,

Central Repeater
Kenwood TKR 750 repeater
TX: 138.9000 MHz
RX: 143:9000 MHz
(No Link Radio)

Remote Repeater 1
TX: 138.1000 MHz
RX: 143.1000 MHz
RF Link
TX: 143.9000 MHz
RX: 138.9000 MHz

Remote Repeater 2
TX: 138.0000 MHz
RX: 143.0000 MHz
RF Link
TX: 143.9000 MHz
RX: 138.9000 MHz

Remote Repeater 3
TX: 138.5000 MHz
RX: 143.5000 MHz
RF Link
TX: 143.9000 MHz
RX: 138.9000 MHz

At the main high site (Central Repeater) they is one Kenwood TKR 750 repeater, at the remote sites we have three Kenwood TKR 750 repeaters link to ICOM CS-F521 as RF link radios at the individual locations.
All link radios are configured for duplex; I am using a Yagi antenna with all the link radios pointing to the central repeater, along with vertical ground plane antennas with the repeaters.

 

[zz0468]

When you say you can transmit but not receive, is that referring to the hub location, or at the remote sites? We need more details as to what's actually happening.

Your frequency spacing is doable, but keep in mind that in one case, you have a transmitter only 400 KHz from a receiver. In all cases, you will have to pay attention to receiver desense. You've given us no clue as to what you're doing to keep transmitters away from receivers.

I will assume for now, since you didn't mention it, that your RF filtering or lack therein is what the problem is.

 

[zz0468]

I am trying to link the radios without voter/distribution amplifier Is that possible?

In the hub configuration that you're building, yes, it's possible. It's simple, not real elegant, but it CAN be made to work. There are some fundamental flaws with what you're doing, but not fatal flaws.

 

[kayn1n32008]

You really need to flip your hub pair around. It will make your life much much much easier. If the hub pair were to be flipped, then you would have maximum separation between your link receivers and your repeater transmitters(and vies-versa, your link transmitters and repeater receivers). With proper vertical antenna separation between repeater and link antennas, and high spec (90+DB isolation) duplexer on the repeater, it can be done. How much power do you need to link the remote repeaters to your hub? If you keep the link radio power output down to a reasonable (5-10w) level you should be ok.


Sent from an unknown place...

 

[kayn1n32008]

Delete




Sent from an unknown place...

 

[jim202]

Hi all I am building a simulcast VHF LMR network at four remote locations using
four Kenwood TKR 750 repeater. I am using three ICOM CS-F521 radios as RF link, both
repeater and RF link radio is connected via OPC-617/DB9 to DB25 cable. I can TX but
no RX, so far the configuration seems to be ok but I not am sure if I left out any
area in the configuration.
I will appreciate all the help from you guys in resolving this problem .

You are really asking to be led down the merry path looking for the kind of technical information you need on a scanner web site. Sure there are a number of technical people on here, but there are better places to get real answers.

 

[cabletech]

tangobrovo It has not been made clear, so I have to ask.

First off, what kind of area are you trying to cover that requires 4 repeaters?

You should be able to cover 30-50 mile area with just 1 repeater.

Are the repeaters TX/RX in a normal manner by themselves?

Are you using the Icoms just to link the 4 sites or are you also using them are access into the repeaters?

I see a major problem here if the Icoms are ONLY for linking, as you do not want to use the same frequency band for linking as the repeaters are using.

You need to use either 220mz or 440mz for the link.

Now if the Icoms are recievingans sending PTT and audio to the repeater but NOT transmitting the audio for the repeater, then you have the problem in the Icom.

There are a couple of mods you need to due to the Icom to make them work.

Go to repeaterbuilder/com and look at what he has posted on connecting Icoms as repeaters.

This is the same thing you need to do to connect to the Kenwood.

also, you show a tx of 143.900 with rx of 138.900 on all of the link radios. this will not work.

If you are linking two radios, then the tx of 1 radio needs to be the rx of the 2nd radio.

 

[dcr_inc]

143.900 is an input freq for the Civil Air Patrol.. They may get a little upset if you are using that freq..

 

[Tangobravo]

Ok,
the reason for the four repeaters is because of the mountainous terrain of my country which in the Caribbean.

 

[kayn1n32008]

tangobrovo It has not been made clear, so I have to ask.

First off, what kind of area are you trying to cover that requires 4 repeaters?

You should be able to cover 30-50 mile area with just 1 repeater.

Are the repeaters TX/RX in a normal manner by themselves?

Are you using the Icoms just to link the 4 sites or are you also using them are access into the repeaters?

I see a major problem here if the Icoms are ONLY for linking, as you do not want to use the same frequency band for linking as the repeaters are using.

You need to use either 220mz or 440mz for the link.

Now if the Icoms are recievingans sending PTT and audio to the repeater but NOT transmitting the audio for the repeater, then you have the problem in the Icom.

There are a couple of mods you need to due to the Icom to make them work.

Go to repeaterbuilder/com and look at what he has posted on connecting Icoms as repeaters.

This is the same thing you need to do to connect to the Kenwood.

also, you show a tx of 143.900 with rx of 138.900 on all of the link radios. this will not work.

If you are linking two radios, then the tx of 1 radio needs to be the rx of the 2nd radio.

The OP is not using ham band so 220Mhz or 440Mhz is out.

Cable tech, go re-read what the OP is trying to do. The first repeater is being used as a 'hub' repeater to link the other 3 remote repeaters. Yes it can be done in band, but he needs to reverse the hub pair to get maximum transmitter/receiver separation for his link radios at the 3 remote sites.

While one can usually get 50 miles on flat terrain, try that in the mountains on sub optimal sites or with sites that do not have 300+ Foot towers...




Sent from an unknown place...

 

[kayn1n32008]

143.900 is an input freq for the Civil Air Patrol.. They may get a little upset if you are using that freq..

IF he was in the USA... Remember this is an international forum...


Sent from an unknown place...

 

[zz0468]

You really need to flip your hub pair around. It will make your life much much much easier.

There could be a good reason that the pair isn't flipped around. I'm not familiar with the rules in the OP's country, but all the frequency pairs are 5.00 MHz separation, and the repeaters are high in, low out. If that's required, and the "hub" is also acting as a mobile relay, then the frequency configuration is what it's going to be.

It's going to take a substantial amount of filtering at all sites except the hub, but it CAN be done.

 

[kayn1n32008]

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You really need to flip your hub pair around. It will make your life much much much easier.

There could be a good reason that the pair isn't flipped around. I'm not familiar with the rules in the OP's country, but all the frequency pairs are 5.00 MHz separation, and the repeaters are high in, low out. If that's required, and the "hub" is also acting as a mobile relay, then the frequency configuration is what it's going to be.

It's going to take a substantial amount of filtering at all sites except the hub, but it CAN be done.

Agreed zz. While not impossible, to do with how it he laid it out to us, the OP's job of inband linking, if the OP can flip the hub pair, will be much, much easier.

 

[Tangobravo]

Hello Guys,
Let me say thanks for the help you all offer to me. However I got through with the network, the no RX was due to faulty RF Link Radios which got damage in a previous installation.

Thank
Coax