KENWOOD TKR-840 Repeater

[Tuckerman]

Hello I am in the process of setting up a Kenwood TKR-840 Repeater on a GMRS frequency pair.

I have everything except the jumpers and feed line and am trying to figure out if jumper length matters much at all.

Will be ordering RG-214 to go between repeater / duplexer / amplifier.

The Kenwood TKR-840 has BNC female type connectors on the back of it.

The duplexer has Type N female connectors on it.

The amplifier has SO-239 connectors.

Does the length of the jumper between each unit matter at all or should i just get a length that will reach between each unit comfortably?

 

[mmckenna]

The jumper length matters between the individual duplexer cans, but not the rest of the gear. Obviously you want to keep it short, but make it easy.

I'd recommend using Heliax Superflex, they've got a 3/8" coax that works well for these sorts of jobs. Its a bit more cost, but over the life of the system, it's small.

 

[Tuckerman]

The jumper length matters between the individual duplexer cans, but not the rest of the gear. Obviously you want to keep it short, but make it easy.

I'd recommend using Heliax Superflex, they've got a 3/8" coax that works well for these sorts of jobs. Its a bit more cost, but over the life of the system, it's small.

Is there a place online I can build to order the heliax superflex? I have used usacoax.com before for RG-214 and LMR-400 cable builds but they do not have Hexliax.

 

[Tuckerman]

And also is the EXT REF IN worth hooking up?

 

[mmckenna]

Is there a place online I can build to order the heliax superflex? I have used usacoax.com before for RG-214 and LMR-400 cable builds but they do not have Hexliax.

I usually order my stuff from Tessco. www.tessco.com They are not build to order, but they've got a huge selection.
They have a $50 minimum order, but you shouldn't have an issue with that.

There's probably a ton of others that will do build to order, but none coming to mind at the moment.

It's not horribly difficult to do yourself. Terminating Heliax is easier with the right tools, but you can do it with simple hand tools. A sharp razor blade, an E-xacto razor saw, maybe a small hand file, and appropriate wire cutters, wrenches, etc. will do the trick.
It'll save you some money, and it's a good skill to learn. The nice thing about the Heliax connectors is that the come apart easy, so if you really screw up, you can take them apart, cut off the end of the coax, and do it over.

 

[mmckenna]

And also is the EXT REF IN worth hooking up?

No.
It's there to provide a 10MHz (I think, I'd have to look it up) reference frequency to help with the keeping the repeater exactly on frequency. It'll run just fine without it. If you are using this on amateur or GMRS, it isn't necessary. Some commercial UHF stuff has a tighter frequency stability requirement, but the repeater will meet those on it's own. If the high spec clock was required, it'd be built in. It wouldn't get FCC certification without it.
Anyways, adding a 10MHz frequency source can get a little expensive.

 

[Tuckerman]

I usually order my stuff from Tessco. www.tessco.com They are not build to order, but they've got a huge selection.
They have a $50 minimum order, but you shouldn't have an issue with that.

There's probably a ton of others that will do build to order, but none coming to mind at the moment.

It's not horribly difficult to do yourself. Terminating Heliax is easier with the right tools, but you can do it with simple hand tools. A sharp razor blade, an E-xacto razor saw, maybe a small hand file, and appropriate wire cutters, wrenches, etc. will do the trick.
It'll save you some money, and it's a good skill to learn. The nice thing about the Heliax connectors is that the come apart easy, so if you really screw up, you can take them apart, cut off the end of the coax, and do it over.

Thank you so much for the information, I have decided to go heliax if no fancy tools are required. I have plenty of wrenches and cutters.

I have signed up at tessco and am having a little trouble finding the right connectors I think.

I purchased some 3/8 and 1/2" heliax I found for cheap and plan on using the 1/2" for the antenna run and cutting the 3/8 up into jumpers, just need to find the correct connectors.

 

[cmdrwill]

Talley Communications also makes custom cables. https://www.talleycom.com/

Do NOT use 'LMR type' cables for repeaters.

 

[Tuckerman]

Talley Communications also makes custom cables. https://www.talleycom.com/

Do NOT use 'LMR type' cables for repeaters.

Hello thank you for replying.

I will be using a 35' run of Acome HPL 1/2" Heliax for the feedline between antenna and duplexer and I got a 25' run of 3/8" Andrex Heliax that I was going to use to make jumpers between the repeater / amp / duplexer but I cannot find BNC male connectors for 3/8" only 1/4".

Should I just make the jumpers out of 1/4" heliax?

 

[brushfire21]

I have used 1/4" heliax without issues for jumpers on VHF/UHF repeaters.

 

[Tuckerman]

I have used 1/4" heliax without issues for jumpers on VHF/UHF repeaters.

Hello Thank you for replying have you used pl 259 on 1/4" heliax before. I can find the BNC and N connectors I will need but cannot find th e pl259

Thank you.

 

[N4GIX]

You don't need any special PL259 for 1/4" superflex heliax. Here is an illustrated guide for installing PL259 connectors:

Using Andrew FSJ1-50A 1/4" Heliax with PL-259 Connectors

 

[cmdrwill]

Just make sure you use newer 'PL259 Type' connectors with delreon or teflon insulation. The 'brown' insulation is no good at VHF and up.

I know I have some NOS genuine Andrews 1/4 superflex jumpers with 'PL259 type' connectors in the storage bin....