SWR'ing a K40

[Captain Kilowatt]

... not to be "nit-picky", but,......... that's a word you don't see often used on a CB radio thread.

That's because most CBers are not pedantic.

 

[91NR529]

so, how tall aprox. the K40's whip for the best VSWR ?
Mine could not get even the good one.
Pls share.
Thank you.

 

[edfiero]

I have the K30 antenna. Same thing as the K40 just shorter. I had to trim the whip to get decent SWR, the built in adjustment wouldn't let me go below 3:1 on CH 40

 

[9C1Driver]

so, how tall aprox. the K40's whip for the best VSWR ?
Mine could not get even the good one.
Pls share.
Thank you.

That would depend on what channel or band you are trying to tune to. As an example on the 11m cb band you should be able to bottom the rod out and then lift it up just a pinch (1/8 an inch). The SWR should be decent at that point. Then you can do the following.

ADJUSTING "LONG" ANTENNAS
If the SWR on channel 40 is greater than that on channel 1, your antenna is considered to be "LONG" and reduction of physical height and/or conductor length will correct this situation. Depending upon antenna model:

1) Firestik II, Firefly Screw down the tunable tip
2) Firestik, Road Pal, and cheap truck stop antennas Remove the tip, make short slits in the plastic covering and unwind and clip off short pieces of wire.
3) Wilson Fiberglass remove cap and lower stinger (cut if on bottom)
4) K-40 Fiberglass Slide the tuning sleeve down (may also use the procedure in step 2 if slide doesn't have enough range)
5) Wilson 1000, 2000, 5000, 500, Lil' Wil , and K-40 base load remove the whip and Cut 1/4" off of the bottom.


ADJUSTING "SHORT" ANTENNAS
If SWR on channel 1 is greater than that on channel 40, your antenna is considered to be "SHORT" and increasing the physical and/or electrical length of the antenna is required to correct this situation.
1) Firestik II, Firefly unscrew the tunable tip
2) Firestik, Road Pal, and cheap truck stop antennas add length with a spring, quick disconnect or extension shaft.
3) Wilson Fiberglass remove cap and raise the stinger
4) K-40 Fiberglass Slide the tuning sleeve up
5) Wilson 1000, 2000, 5000, 500, Lil' Wil , and K-40 base load raise the whip.

 

[Slowmover]

That would depend on what channel or band you are trying to tune to. As an example on the 11m cb band you should be able to bottom the rod out and then lift it up just a pinch (1/8 an inch). The SWR should be decent at that point. Then you can do the following.

ADJUSTING "LONG" ANTENNAS
If the SWR on channel 40 is greater than that on channel 1, your antenna is considered to be "LONG" and reduction of physical height and/or conductor length will correct this situation. Depending upon antenna model:

1) Firestik II, Firefly Screw down the tunable tip
2) Firestik, Road Pal, and cheap truck stop antennas Remove the tip, make short slits in the plastic covering and unwind and clip off short pieces of wire.
3) Wilson Fiberglass remove cap and lower stinger (cut if on bottom)
4) K-40 Fiberglass Slide the tuning sleeve down (may also use the procedure in step 2 if slide doesn't have enough range)
5) Wilson 1000, 2000, 5000, 500, Lil' Wil , and K-40 base load remove the whip and Cut 1/4" off of the bottom.


ADJUSTING "SHORT" ANTENNAS
If SWR on channel 1 is greater than that on channel 40, your antenna is considered to be "SHORT" and increasing the physical and/or electrical length of the antenna is required to correct this situation.
1) Firestik II, Firefly unscrew the tunable tip
2) Firestik, Road Pal, and cheap truck stop antennas add length with a spring, quick disconnect or extension shaft.
3) Wilson Fiberglass remove cap and raise the stinger
4) K-40 Fiberglass Slide the tuning sleeve up
5) Wilson 1000, 2000, 5000, 500, Lil' Wil , and K-40 base load raise the whip.

All this screwing around: just get a Skipshooter and you’ll nail it first time.

.

 

[Handy Andy]

Ok, that reminds me, you can add a Nail (3d Penny or longer) if you're coming up short...even a "lead sinker" from a fishing kit on the tip to help.

But so you know the O.P. was...

Last heard from 4 years and 40 weeks ago...
​

@91NR529 - The whip you should use is 58" nearly 5 feet in length.

so, how tall aprox. the K40's whip for the best VSWR ?
Mine could not get even the good one.
Pls share.