Coax jumpers

[VETCOMMS]

I have 7/8 Andrews LDF 5 hardline and want to make a smaller diameter jumper that goes from the hardline to the N-type female connector on the antenna.   

Are there any cable builders that can do this?  Any recommendations or links to get custom made jumper cables?

[WRYZ926]

ABR Industries will make just about any cable you want and their prices are reasonable. https://abrind.com

I have a few cables and jumpers from them and they are good quality cables.

 

[SteveShannon]

5 hours ago, VETCOMMS said:

I have 7/8 Andrews LDF 5 hardline and want to make a smaller diameter jumper that goes from the hardline to the N-type female connector on the antenna.   

Are there any cable builders that can do this?  Any recommendations or links to get custom made jumper cables?

Depending on the connector on the hardline you should be able to just order a jumper from DX Engineering (they will also do custom) or Gigaparts or Ham Radio Outlet. All sell short jumpers with nearly any end. I have several LMR400 and UG8X jumpers for the last few feet. 

[VETCOMMS]

Thx for that.  What do most people use for jumpers at the antenna end to decrease drag/ weight on the antenna?  Similarly what do people use at the end going to the repeater?

Is 1/2" LDF4 heliax still to large/ cumbersome to use at the terminations?  Should I go smaller?  Are there conductor differences going from Heliax LDF5 to,  say LMR400 or UG8X that could adversely affect performance?

This is going on my garage,  max 30 feet up to get to learn how to use hardline, install the N-type fittings from Pasternack on my Heliax LDF5 and how to install these jumpers to reduce coax size going into the building to the repeater and to attach to the antenna. 

The goal is to learn how to do this at my home first before I move the repeater to a higher location. 

[SteveShannon]

5 hours ago, VETCOMMS said:

Thx for that.  What do most people use for jumpers at the antenna end to decrease drag/ weight on the antenna?  Similarly what do people use at the end going to the repeater?

Is 1/2" LDF4 heliax still to large/ cumbersome to use at the terminations?  Should I go smaller?  Are there conductor differences going from Heliax LDF5 to,  say LMR400 or UG8X that could adversely affect performance?

This is going on my garage,  max 30 feet up to get to learn how to use hardline, install the N-type fittings from Pasternack on my Heliax LDF5 and how to install these jumpers to reduce coax size going into the building to the repeater and to attach to the antenna. 

The goal is to learn how to do this at my home first before I move the repeater to a higher location. 

For the jumper at either end you typically want something very flexible.  The shorter the jumper the more flex you want.  LMR 400 isn’t very flexible because it has a solid inner conductor, but M&P makes two different 10 mm (same diameter as LMR400) cable types with stranded center conductor. One is called Ultraflex 10 and the other is called Hyperflex 10.  Most of the cable manufacturers do something similar.  For more flexibility you can even go to smaller sized cable, such as M&P Ultraflex 7.
It really depends on you setup, but for example I have an 18” piece of RG8x going between my radio and my SWR/Wattmeter, then a six foot piece of some flexible coax that is similar to LMR 400 except with a stranded center conductor.  I think it’s M&P Ultraflex 10 or maybe the ABR equivalent. That leads to the pass through/lightning protector.

Yes, there are conductor differences.  The thinner, more flexible jumpers have more attenuation, but because they are short the loss doesn’t matter much. That’s the only way it will adversely affect performance, but that’s the trade off and it’s doubtful you’ll ever notice the slight loss.

[WRYZ926]

There is also LMR400 Ultraflex which is a bit more flexible. You can use some quality RG8X if the jumpers are say 6 feet or less. There won't be much loss at such short lengths.

[gortex2]

In the LMR world we use 1/2" LDF for jumpers at the antenna regardless of size of feedline. Then from polyphaser to repeater/combiner/duplexer 1/2" superflex or 1/2 LDF depending on the PIM rating needed. My 7/8" feedline terminates with 7/8 din, then 1/2" LDF to the DB408 on one of my towers. Most antenna jumpers are 6' long but that all depends on the side arm needed on the tower. My DB408 is on top of tower so I use a 3' jumper.