Does different coax affect swr?

[phantom309]

Forgive me but the project in question is at home and I'm on the road currently.

I'm not getting into another coax length battle, so here we go.

Current setup,

Sirio performer 5000, lmr 400 ultraflex to the radio.

Soon to be adding something between the radio and antenna, say for the sake of argument a meter......, yeah a very big power hungry meter. I currently don't have a lmr 400 ultraflex jumper to go from the radio to the......, meter. So can I get away with using an old rg8 jumper for the time being until my new order comes in? Or should I just wait till the next time I get home?

 

[Tallman]

As long as it is 50 ohm coax no problem.

 

[338_MtRushmore]

The coax won't affect the vswr. I can't comment on if it is ok to use rg8, because you haven't provided enough info. For all I know it is a 2970N4 driving something very hungry? If a normal cb or dual final export I would run with it for now, but that's just me.

 

[phantom309]

Galaxy 98 vhp, about 170ish pep

 

[338_MtRushmore]

Galaxy 98 vhp, about 170ish pep

Run it if it is decent quality and not 90 feet long

 

[phantom309]

Thanks.

 

[338_MtRushmore]

That's more power than I was guessing. What are you driving with that bad boy?

 

[phantom309]

Straight 8.

 

[fourstringburn]

rg8 jumper

Rg8 is fine for jumpers. I use RG8/U because I prefer larger coax for jumpers and it's flexible for it's size and I use RG213/U for outdoor HF cable runs because it has better U/V properties to last longer outdoors.

You can mix and match RG8X and RG8 and 213 for jumpers and cable runs although I would suggest the antenna cable run be one long piece to the antenna, balun, etc.

Don't get too hung up on cable spec's like velocity factors and DB loss on HF bands including CB. The LMR 400 type cables were intended for the much shorter wavelength VHF and UHF frequencies due to the higher losses where the RG8 types are for the broader frequency ranges below 30 MHz. Even LMR 400 is inefficient compared to 7/8 in. Heliax cable.

You can still use LMR 400 for HF.

 

[Captain Kilowatt]

As long as the coax you use is 50 ohms it doesn't matter what the type is. It could be RG8, RG-58, RG-213, LMR-400 or LDF4-50 heliax.

 

[w9cll]

I am using RG8x to my dipole, its a run of about 35'. I don't feed it more than 150w. When I had the VHF stuff up I ran hard-line from the shack to the rotor point and RG8 to the antennas.

 

[fourstringburn]

I should have answered your question better, Different coax sizes and types do not affect SWR as long as they are all 50 ohm coax cables.

 

[Captain Kilowatt]

I am using RG8x to my dipole, its a run of about 35'. I don't feed it more than 150w. When I had the VHF stuff up I ran hard-line from the shack to the rotor point and RG8 to the antennas.

You should see my runs. I use RG-8x for most patch cords but also some RG-8. I have some Beldin 8214 which is an RG-8 type as well and there may even be a lost piece or two of RG-58 in the mix as well. This all eventually connects to LDF4-50 heliax to the rotor loop and then more RG-8 type from there. Since it's all 50 ohms it doesn't matter.

 

[midnight special]

as long as it is 50 ohm it is fine,,, on my pick up i use belden rg213 9 foot long from antenna to amp then from amp to radio a 6 foot belden rg8x,,,

 

[phantom309]

Thank you all for the replies, in case you wondering why I am using the lmr400uf, it because I got enough for my for free from a friend that bought a spool of for his installation. He had about 50 feet he gave away. I got enough for my run, but forgot about jumpers at the time.