Help With Repeater Using 2 TK-880s?

[DeoVindice]

I've been doing some research on building a light-duty portable GMRS repeater and have decided to use a pair of TK-880s for ease of programming and FleetSync compatibility. Where I haven't been successful is in finding a layout diagram for this arrangement, or programming guidance for the TX radio. N0KEG decently covers the RX radio's programming.

 

If possible, I would omit the repeater controller to save space and weight. Would the following arrangement work, or is a repeater controller 100% required?

 

- TK-880 RX radio connected to battery and high/receive side of duplexer

- TK-880 TX radio connected to battery and low/transmit side of duplexer

- KCT-19 cable connecting RX and TX radio

- Antenna connected to duplexer antenna connector

[WRAK968]

I believe the KTC 19 was designed for external I/O triggers (Horn alert and computer hookup for text and data traffic)

However, I have just built a portable repeater using 2 TK880's so its an easy question to answer. I used a surecom 629 repeater controller which is lightweight and designed for portable repeater use. It even has an internal battery to power itself with if you don't have a way to power it directly. The real selling point for the surecom was that they make a plug and play kit for the 880 series radios. the RX end plugs into the speaker port, the TX plugs into the mic port of the TX radio. The entire set-up including a USB charger for the surecom and duplexer all fit into a box the size of an ammo can.

 

Equipment used:

2 TK880 radios (one RX, one TX and note the TX radio should be run at low power to increase the PA's life during continuous operations)
1 surecom 629 repeater controller

2 surecom 48-k1 cables (one for RX one for TX)

1 Celwave UHF duplexer (flat pack)

1 GDS tech USB charger 3A (For keeping the surecom powered during long term operations)
1 6 post fuse block from Autozone
1 Zjelen XHP20 2 pole power connector (to pass power into the box while keeping it waterproof)

various jumpers and wires for running power and connecting the duplexer.
1 waterproof box from walmart about the size of an ammo can

 

wireing up the unit is straight forward. I used the fuse block to supply +12V to each radio (each radio has its own fuse) and one post to power the USB charger. I mounted the celwave duplexer first, then using dual lock velcro (the heavy duty stuff) mounted each radio, then the surecom controller.

 

The cellwave used BNC inputs so I snipped off the SO259 ends from the TK880's and soldered on BNC males so the radios plug directly into the duplexer, less connectors and wire = less loss. I then ran a short length of low loss jumper wire to add in a bulkhead "N connector for the antenna. This allows me to operate the repeater with the box closed, thus keeping the unit waterproof. I just ran all the connections, did a little cable management, and I was set. I get about 9.5W out on low power, and about 23.8W out on high power (high power can be used but should be intermittent to prevent PA failure or overheat, remember these radios have a 20-80 duty cycle, thats 20% or 12 minutes TX and 80% or 48 minutes resting per hour on high.)

Outside of the build, you will need an antenna, coax, and a good deep cycle battery. I tried an 18Ah battery I use as a backup but I found I only got about 14 hours use if that. So I upgraded to a trolling motor battery which I think was 150Ah, I plan to test that out this week. NEVER USE YOUR CARS MAIN STARTING BATTERY!!! It'll drain it quick and you'll be stuck with a dead car.

I know its a lot of info but I hope this all helps.

**edit** For some reason MyGMRS says I do not have permission to post pictures here, not sure why. If you would like to see what the finished product looks like feel free to message me and Ill see if I can send em that way!

[DeoVindice]

That sounds like an excellent design. PM inbound.

[password]

My current repeater is actually two Kenwood TK-800s

 

I fallowed this for the RX radio and poped our an RJ-45 out the back of the radio.

http://n0keg.com/index.php/2017/10/02/kenwood-tk-880-as-a-receiving-radio-for-a-repeater/

 

The controller is just a Raspberry PI running open repeater, I forget what kind of pi I used as I had it laying around.

 

The TX radio is completely Unmodified, and has ran solid for over two years

 

Here’s some old pictures of it getting built and where it is now, the duplex is also different now then in the pictures

 

https://imgur.com/a/qo1c28w

[WRAK968]

My current repeater is actually two Kenwood TK-800s

 

I fallowed this for the RX radio and poped our an RJ-45 out the back of the radio.

http://n0keg.com/index.php/2017/10/02/kenwood-tk-880-as-a-receiving-radio-for-a-repeater/

 

The controller is just a Raspberry PI running open repeater, I forget what kind of pi I used as I had it laying around.

 

The TX radio is completely Unmodified, and has ran solid for over two years

 

Here’s some old pictures of it getting built and where it is now, the duplex is also different now then in the pictures

 

https://imgur.com/a/qo1c28w

The only downside to this is that it looks like there is quite a bit of soldering to be done, both inside a radio and externally. The surecom is just plug and play and about the same price as all the components and the pi itself. Guess its a matter of ease of setup and what features you would like.

[WRZT722]

On 10/22/2019 at 7:49 PM, password said:

My current repeater is actually two Kenwood TK-800s

 

I fallowed this for the RX radio and poped our an RJ-45 out the back of the radio.

http://n0keg.com/index.php/2017/10/02/kenwood-tk-880-as-a-receiving-radio-for-a-repeater/

 

The controller is just a Raspberry PI running open repeater, I forget what kind of pi I used as I had it laying around.

 

The TX radio is completely Unmodified, and has ran solid for over two years

 

Here’s some old pictures of it getting built and where it is now, the duplex is also different now then in the pictures

 

https://imgur.com/a/qo1c28w

Do you have the pinout on the front mic input as to where to connect the rx radio?