antenna swr q

[Se7en]

Wilson 5000 roof mount, get flat swr thru all 40 barefoot but, when amp is kicked on swr goes 3.0 & thru the roof. when using a 10k swr is 1.3 with amp kicked on, both antennas mounted in the same place how ever 10k is mounted with a beehive while the Wilson 5000 uses the stock mount. 4' coax from radio to amp, 3' coax from amp to meter, 15' coax from meter to antenna on either antenna..... any ideas? cant be a ground issue checked that. is Wilson broke? maybe its just a duck antenna ......:headbang
i know cb 11meter is 36' .... and i doubt its a coax length issue? lmr400 is used from meter to antenna 15'. the rest is RG8 mini.
all ready tried adding 2 more feet to get it to 24'. still the same.:thumbdown:

 

[gamegetter]

it is very likely something wrong with wilson 5k or coax. is it a new 5k or did you get it used? if used then suspect something wrong with it. does anything rattle when you take antenna off and shake it?

how much power are you running? op:

 

[tvrc18]

I would not use a mag mount when running power, it may work ok but I would rather have a antenna mounted and an extra ground wire to the frame to make sure I have a good ground..

 

[gamegetter]

what do you mean by "stock mount" morse123 ?

Is it through roof mount or mag mount?

 

[Se7en]

my bad. it is a roof mount i never run mag mounts. 5000 is three months old (nothing inside rattles checked it with a analyzer) . 500w amp.

i was told that with an amp off but inline if swr is flat and when amp turned on if swr goes high its just a harmonic issue....? just don't want to ruin the life of the amp. + it would be nice to see a flat swr with amp on.

 

[gamegetter]

what is the length of the whip on the wilson 5k?
reason I ask is there are some that came with a 66" whip that may not match up and exhibit such behavior.

 

[hotrod]

never had this happen to me. so im just guessing here but will he wilson
screw onto the beehive mount? only variable i see . if not guess the 10k handles power better ..maybe?

 

[gamegetter]

has to be something simple, that wilson will handle alot more than that.

 

[Se7en]

the whip is cut @ 58" that's the best length for flat swr barefoot. i have a brand new 62.5" whip but that brings swr high barefoot. NO the Wilson will not screw into the beehive mount. i have eliminated the stock Wilson lower roof mount and use a washer and a female straight barrel connector so i can use lmr 400 + better ground. i tried the stock RG8 & mount with the antenna with the same results. i was told to try adding a longer piece of coax between the amp and radio so i going to try that after lunch and see what happens. i have tried different length between amp and meter and meter and antenna still high last is the radio to amp.
yes, the Wilson will handle allot more power then 500w.
the 10k sucks mobile because when driving swr bounces up and down on the meter as to the Wilson it never moves. i think my 10k is broken. ill post back in a little while how it goes with the other coax between amp and radio.

 

[gamegetter]

i would check continuity of coax, be sure to disconnect at radio and at mount, braid to center core there should be no reading.

 

[gamegetter]

i'll wait before my next question

 

[Se7en]

ok so i took the lmr out of line and stuck 19 feet of RG58 radio shack coax from antenna to meter... it read 3.0 flat so i put the lmr back and removed the 3 foot jumper between amp and meter and stuck the 19' there and swr is 1.2 across the whole bad and below and above with amp on. i measured the coax between the radio and amp its 5' so we have 15' + 19' + 5'... = 39' of coax.... well i guess i fixed my problem.
all of my coax is perfect no cold joints no broken spots or kinks or issues. i always make sure of that every month maintenance is my top priority.

 

[Robb]

I think that if a 1/4 wave length jumper coax is used; it might act as an impedance matcher between the amp and radio. This could be done; but it might tell a larger story. It may mean that the amp's input impedance may be off.

Thoughts?

 

[gamegetter]

i had been suspecting that barrel connector thingy, i don't particularly like the sound of that...any moisture in there and you can ground out real fast.

morse did you set the amp to key 1/4 of it's pep out?

also I think that the antenna is no longer resonant.

 

[Se7en]

i had been suspecting that barrel connector thingy, i don't particularly like the sound of that...any moisture in there and you can ground out real fast.

morse did you set the amp to key 1/4 of it's pep out?

also I think that the antenna is no longer resonant.

the barrel connector no way moisture is going to get in.
yes i reset radio to key the amp @ 125w. (seems to be the best sweet spot).

why would the antenna not be Resonant?

i looked up Resonant...


In physics, resonance is the tendency of a system to oscillate with larger amplitude at some frequencies than at others. These are known as the system's resonant frequencies. At these frequencies, even small periodic driving forces can produce large amplitude oscillations, because the system stores vibrational energy.