Base will any change

[1iwilly]

ok so i finally got the major stuff out of the way and ordered a new 75' ft Coax Cable Low Loss Double Shield RG213U Non-contaminating BR213DS PL259
at the moment I'm running rg8x double shielded my main question am I going to need to re-adjust SWR been they are 1.1. now and upgrading to a better coax anybody ever had major issues when upgrading never dealt with base-station before all my CB days from 1996 to 2007 where all mobile setups

 

[sp5it]

Hard to say since you don't know SWR at the feedpoint nor measurement gear and methodology.

 

[1iwilly]

Hard to say since you don't know SWR at the feedpoint nor measurement gear and methodology.

at the feed, point is 1.0/1.1 SWR meter both external and internal on radio reflect at 300watts is 1 watt on bird meter on sirio2016 antenna,between radio and amp also 1.1

 

[sp5it]

At 75 feet you won't see or hear any difference unless old coax was crap.

 

[1iwilly]

At 75 feet you won't see or hear any difference unless old coax was crap.

well the reason for the change =power handling/rating of the rg8x is the DB loss at 75ft. i will be increasing power down the road with a bigger amp so i guess a security blanket

 

[sp5it]

 

[nomadradio]

Haven't heard this one in a while, but back in the day I would hear from a base station operator who had just changed his 15 or 20 year-old coax. The complaint would be that his SWR had just "jumped" up from the near-zero reading with the old coax to 1.3 or 1.4 with the new cable. He would be distraught, wondering what to do about his SWR "increasing".

I would congratulate him on improving his signal strength on transmit, followed by a puzzled look in return. I explained that the low SWR reading was caused by high losses in the old, oxidized coax cable. The higher SWR reading is what he would have read with the meter placed at the feedpoint of the antenna. But the reflected power was being dissipated in the coax, so that almost none of the reflected power would reach the ground. Pointing out that the forward power that actually reached the antenna was being lost the same way would get some recognition that this "higher" reading is a good thing, not a technical fault.

73

 

[AudioShockwav]

Agree with Nomad, when I first got my I10K from Jay, we put to together and shoved it up on top of my 2 story house.
I used the sheet in the box to chart SWR and it was wide.
Very wide, covered almost 3mhz, so much so that I called Jay on the phone and talked to him about it.
First question was how is your coax?
It had seemed fine, I was using the same 213 that I had on my A-99 and it was old.
I went and picked up 75 feet of new 9913, installed connectors and replaced the old 213.
SWR readings fell right into place as Jay said it would.
Later inspection showed water ingress into the coax had caused sections of the shield to turn green and oxidize.
I wish I had the fore thought to put a dummy load and power meter at the end of the coax run on the old and new coax.
I suspect that I was wasting power in the coax that never made it to the feed point.
Low SWR does not always mean everything is working at its best.

73
Jeff

 

[1iwilly]

Agree with Nomad, when I first got my I10K from Jay, we put to together and shoved it up on top of my 2 story house.
I used the sheet in the box to chart SWR and it was wide.
Very wide, covered almost 3mhz, so much so that I called Jay on the phone and talked to him about it.
First question was how is your coax?
It had seemed fine, I was using the same 213 that I had on my A-99 and it was old.
I went and picked up 75 feet of new 9913, installed connectors and replaced the old 213.
SWR readings fell right into place as Jay said it would.
Later inspection showed water ingress into the coax had caused sections of the shield to turn green and oxidize.
I wish I had the fore thought to put a dummy load and power meter at the end of the coax run on the old and new coax.
I suspect that I was wasting power in the coax that never made it to the feed point.
Low SWR does not always mean everything is working at its best.

73
Jeff

thanks like i stated the rg8x is 1 year old my question was should it change SWR by installing a different velocity coax the same length of 75ft and the Sirio 2016 is not even a month old yet wish i could of done it all in one shot but money was an issue at the given time thanks for the inputs

 

[W4KVW]

well the reason for the change =power handling/rating of the rg8x is the DB loss at 75ft. i will be increasing power down the road with a bigger amp so i guess a security blanket

Unless you lost 1/2 of the power nobody can see or hear the difference in the signal.It's physics but it requires doubling of your output for just 1 s-unit of signal increase so most people never see or hear the difference.Unless the old coax was full of water or was badly damaged, I doubt you will see any difference.

SIX-SHOOTER
W4KVW
WRMX520

 

[sp5it]

it requires doubling of your output for just 1 s-unit of signal increase

1s unit is power x4

 

[W4KVW]

1s unit is power x4

YES it takes a LOT of Extra Power. LOL

SIX-SHOOTER