Jumper cable for repeater?

[Hosted]

I am putting up a repeater for our farm. Have 7/8 Heliax on the way from antenna with connectors to inside my building. I need to go another 20-25 feet from the 7/8 to my repeater. I can buy premade pieces of lmr400 or lmr600 or should I buy and try to make a piece of 1/2 heliax? I’d like to use the heliax but don’t want to buy a bunch of special tools for a single cable. 

[gortex2]

I would go Heliax. Order a 25' remade cable. Also remember to put a Polyphaser where the 7/8" entered the building to a ground. 

[Hosted]

I did not have a polyphaser on my list. Is there one that is recommended over others? I see a polyphaser brand as well as a cheap version on Amazon. 

[JeepCrawler98]

31 minutes ago, Hosted said:

I did not have a polyphaser on my list. Is there one that is recommended over others? I see a polyphaser brand as well as a cheap version on Amazon. 

Stick with they PolyPhaser, there's a reason they're the industry standard. Check out the IS-50NX-C2; however there's other configurations available as well.

[OffRoaderX]

I use LMR400 on my repeater for the main run and the shorter patch-cables.. Contrary to what all the experts claimed, it works just fine, and more than good enough for my non-life-critical application..
 

[DONE]

I put 1/2 heliax connectors on for years with nothing but a pocket knife and a couple cresent wrenches to tighten the connector body down.

If you are using Andrew / Comscope connectors they come with a guide for doing this.  Follow the directions and you will be fine.

 

[DONE]

6 hours ago, OffRoaderX said:

I use LMR400 on my repeater for the main run and the shorter patch-cables.. Contrary to what all the experts claimed, it works just fine, and more than good enough for my non-life-critical application..
 

You are right, depending on the cable run length and how often you want to change out the cable.  400 is kinda lossy if it's over 100 feet. 

[n4gix]

On 10/5/2021 at 4:39 PM, OffRoaderX said:

I use LMR400 on my repeater for the main run and the shorter patch-cables.. Contrary to what all the experts claimed, it works just fine, and more than good enough for my non-life-critical application..
 

That is absolutely true for the first X number of years. Eventually though, it will break down and generate a lot of snap-crackle-pop noise in both the receiver and transmitter.

[rdunajewski]

LMR400 is known to have noise (static) issues when used on a repeater. It has to do with the foil and braid being in contact with each other on the shielding, which can cause noise on the RX side when the TX is active. Heliax is preferred over LMR400 or anything else with a foil/braid combo in contact with one another.

LMR400 is perfectly fine for non-repeater use, however.

[gortex2]

If you spent the money for 7/8" it wouldn't make sense to use LMR or something like that for the jumper. Just go with 1/2" hardline jumper and be done.

 

[Hosted]

I ordered 1/2 heliax and connectors today for the jumper. Now I just need to watch YouTube videos to see how to put it together. I put my 7/8 up today and by my measurement it is about 7-8 feet shorter than it was supposed to be so my polyphaser is going to have to be vertical on my tower. Should I just wrap it like a connection? It was a horrible job stringing it up by myself so I’m definitely not taking it down. 

[DONE]

Yes, connect a ground wire to it and then wrap it with butyl and vinyl tape to weather proof it.

Make sure to properly connect the other end of ground wire to a proper ground.

 

[Hosted]

Perfect, thanks! We have ground rods right by the structure to tie into.