Jumper selection (Radio to bulkhead)

[srbecker]

Pretty simple.  I am looking for what you all recommend to run as a jumper(s) from my radio base station to my SWR meter, then from my meter to my bulkhead that my antenna is connected to OR straight from radio to bulkhead if I decide to take out the SWR meter.

I am currently using 2' long LMR-400 jumpers and I get a GREAT SWR with them, BUT they are super stiff and very difficult to deal with as far as cable management.   I am looking for something a little more flexible, unless everyone says to just leave it as is and not mess with a good thing?

[OldRadioGuy]

The cable will not generally affect SWR - just the loss.

A foot or two of coax generally has almost negligible loss.  So you can use anything half decent.  RG141 or even RG316 is very thin and flexible. Check the power handling capacity of  very thin coax to make sure it's adequate but should be fine for GMRS.  Pasternack and Digikey both sell short cables with connectors installed.

 

The odd thing is that lossy coax will actually make your antenna SWR look BETTER.

SWR is based on return loss or reflected power.  Loss reduces the reflected power and thus improves SWR.

I've heard a number of stories about hams who invested in better coax and it "made their antenna worse."

No, it just allowed the meter to see the reflected power better.

 

Vince

[kidphc]

I'd leave good enough alone. If it bothers you 213x is a little more flexible. For most of my jumpers the are either rg58 or lmr200.

Under a foot not much of a difference. 100 feet yeah, notice losses are by the 100 feet?

Sent from my SM-G975U using Tapatalk

[srbecker]

There must have been something up with or wrong with the cables I had then. I got some of those right angle RG-58 jumpers from Amazon and my SWR went from 1.03 up to 1.32 on repeater channels and then from 1.79 on simplex channels to 2.24 after those cables. I didnt like that much, so I ended up returning them and went back to the LMR-400 jumpers I have in the photo above. With that I am getting 1.00 on repeater channels and 1.79 on simplex channels.

I think I am going to just order up a 4' jumper of something a little more flexible and run it (removing the SWR meter) from a full time install to just when needed since I already know I am getting a good SWR.

[kidphc]

There must have been something up with or wrong with the cables I had then. I got some of those right angle RG-58 jumpers from Amazon and my SWR went from 1.03 up to 1.32 on repeater channels and then from 1.79 on simplex channels to 2.24 after those cables. I didnt like that much, so I ended up returning them and went back to the LMR-400 jumpers I have in the photo above. With that I am getting 1.00 on repeater channels and 1.79 on simplex channels.

I think I am going to just order up a 4' jumper of something a little more flexible and run it (removing the SWR meter) from a full time install to just when needed since I already know I am getting a good SWR.

Right angle jumpers are serious hit or miss. Especially, the premade ones. Some times they are barely soldered on the center pole.

Rf doesn't like right angle bends much either. We use loops and the mid point of the loop for long wire antennas (refer to fold backs). Well guess what you can adjust then fold back lengths to tune antenna. Even with a foot hang off the fold back.

So much so that my random wire came with specific instructions to use pulleys to create curves in order to minimize bend radius that will be seen as the electronically the end of the antenna.

Sent from my SM-G975U using Tapatalk

[srbecker]

1 hour ago, kidphc said:

Right angle jumpers are serious hit or miss. Especially, the premade ones. Some times they are barely soldered on the center pole.

Rf doesn't like right angle bends much either. We use loops and the mid point of the loop for long wire antennas (refer to fold backs). Well guess what you can adjust then fold back lengths to tune antenna. Even with a foot hang off the fold back.

So much so that my random wire came with specific instructions to use pulleys to create curves in order to minimize bend radius that will be seen as the electronically the end of the antenna.

Sent from my SM-G975U using Tapatalk
 

I cannot get mygmrs to work on my tapatalk, any advice? lol

[kidphc]

18 hours ago, srbecker said:

I cannot get mygmrs to work on my tapatalk, any advice? lol

You logging in with the same login?  You might need to contact the admin for help.

[n1das]

Check out the video in the link above.

I recommend changing out all of the PL-259 and SO-239 connectors and replacing them with N connectors.  On the mobile radio, use an N female to PL-259 adapter screwed right onto the mobile radio's SO-239.  This is the next best thing to changing the connector on the radio.  Do the same thing at the antenna if the antenna has an SO-239.  Then use N connectors for everything from the mobile radio all the way to the antenna.  Impedance discontinuities (mismatches) caused by connectors contribute to SWR problems and must be avoided.

I will not use a PL-259 (plug) or SO-239 (socket) on anything operating above 30MHz.  Not worth the trouble, including SWR problems.