Questions regarding K40 - SF400 4FT Superflex Whip

[penguin]

I just picked up 2 of these so that I could run dual antenna's
on the truck ..

I got an 18 foot co phase cable routed everything to the new
antenna's and decided to use my old radio just to check them
out .. heres what I got with the SWR meter

Channel 1 - 3.1
Channel 20 - 1.9
Channel 40 - 1.2

I tried adjusting the the whip in the 1/8 inch increments that
they recommend ... ( but at 21 degrees outside its rough )

my question is ... what should I actually be shooting for
when it comes to measurements ... and should I really care
about these since I will be getting a new radio soon ?

 

[Butcher318]

Do you understand how to set the SWR on a co-phase set-up? No insult intended there just checking. The local guy that does it uses a 50 ohm dummy load on one antenna then tunes the other, then switches them around and does it again. I know alot of trucks have some real ground issues as well.

 

[penguin]

woops .. I guess I put this in the wrong forum ..

 

[Hardhead]

Do you understand how to set the SWR on a co-phase set-up? No insult intended there just checking. The local guy that does it uses a 50 ohm dummy load on one antenna then tunes the other, then switches them around and does it again. I know alot of trucks have some real ground issues as well.

When I set mine I used a separate coax to tune each antenna till they were flat. Then I hooked up the co-phase harness and they checked ok together. As long as each antenna is resonate at the same frequency they will co-phase correctly.

 

[penguin]

Do you understand how to set the SWR on a co-phase set-up? No insult intended there just checking. The local guy that does it uses a 50 ohm dummy load on one antenna then tunes the other, then switches them around and does it again. I know alot of trucks have some real ground issues as well.

When I set mine I used a separate coax to tune each antenna till they were flat. Then I hooked up the co-phase harness and they checked ok together. As long as each antenna is resonate at the same frequency they will co-phase correctly.

I went and ran a single coax line and did each individually
and got them to

channel 1 = 2.1
channel 20 = 1.8
channel 40 = 1.5

I will probably just take the truck down to a CB shop and
let the guy there make sure everything is good to go once
I get my new radio

 

[Hardhead]

I went and ran a single coax line and did each individually and got them to

channel 1 = 2.1
channel 20 = 1.8
channel 40 = 1.5

I will probably just take the truck down to a CB shop and
let the guy there make sure everything is good to go once
I get my new radio

You antennas are still too long. Cut them some more. As you cut you will see Ch 40 come to 0.0. You should be able to get Ch 20 to 0.0 with Ch 40 and Ch 1 at about the same. I'm guessing that you will be some where around 1.3 on each end.

 

[Highlander_821]

I went and ran a single coax line and did each individually and got them to

channel 1 = 2.1
channel 20 = 1.8
channel 40 = 1.5

I will probably just take the truck down to a CB shop and
let the guy there make sure everything is good to go once
I get my new radio

You antennas are still too long. Cut them some more. As you cut you will see Ch 40 come to 0.0. You should be able to get Ch 20 to 0.0 with Ch 40 and Ch 1 at about the same. I'm guessing that you will be some where around 1.3 on each end.

_________
I think that is wrong--you need to go a little longer, not shorter.

 

[Hardhead]

I went and ran a single coax line and did each individually and got them to

channel 1 = 2.1
channel 20 = 1.8
channel 40 = 1.5

I will probably just take the truck down to a CB shop and
let the guy there make sure everything is good to go once
I get my new radio

You antennas are still too long. Cut them some more. As you cut you will see Ch 40 come to 0.0. You should be able to get Ch 20 to 0.0 with Ch 40 and Ch 1 at about the same. I'm guessing that you will be some where around 1.3 on each end.

_________
I think that is wrong--you need to go a little longer, not shorter.

YOU ARE RIGHT.....Sorry

 

[penguin]

guys,

these are adjustable tip antenna's .. you dont cut these
you turn a little allen screw to loosen the tip ..

so your saying I should adjust the tip so it make the antenna
longer