Half Wave vertical Cb Antenna SWR

[smipe2001]

Hi all. Im new to the forums and would like to ask a few questions. i currently have a stationmaster antenna on my roof for my home base cb radio. this is a half wave vertical. my swr is 1.2 on ch 1 and 1.5 on ch 40
is this an acceptable swr reading. i know that most people say anything under 1.5 is good however im concerned that 1.5 is too high for ch 40. maybe its just me being paranoid but i thought ch 1 would be 1.1

also when it rains or it is very damp outside and there is a lot of moisture my readings hit the roof and on ch 1 i get a reading of around 1.5 to 1.6 and on ch 40 i get 2.7 to almost 3. is this normal? when it drys and it is sunny outside my readings go back to the normal figers above. thankyou for your time reading

 

[mmckenna]

Hi all. Im new to the forums and would like to ask a few questions. i currently have a stationmaster antenna on my roof for my home base cb radio. this is a half wave vertical. my swr is 1.2 on ch 1 and 1.5 on ch 40
is this an acceptable swr reading. i know that most people say anything under 1.5 is good however im concerned that 1.5 is too high for ch 40. maybe its just me being paranoid but i thought ch 1 would be 1.1

What are you using for an SWR meter?

I wouldn't get too hung up on the numbers. That's pretty good for a CB antenna. If it's easy/safe to get to, you can try moving the tap point on the coil a little bit either way and see if it improves.

also when it rains or it is very damp outside and there is a lot of moisture my readings hit the roof and on ch 1 i get a reading of around 1.5 to 1.6 and on ch 40 i get 2.7 to almost 3. is this normal? when it drys and it is sunny outside my readings go back to the normal figers above. thankyou for your time reading

Not normal.
Make sure the area around the connector is sealed. Same with your coaxial connectors. Water getting into the connections will cause issues. If the area is dusty or high salt content, moisture will cause issues. Make sure everything is cleaned and well sealed.

 

[smipe2001]

thanks for reply

Hi the metre I have is a zetagi TM 999 swr/ antenna matcher. The whole antenna is aluminium as it's a real old station master I was told that water hits the coil and shorts it out and makes the radio think it's a longer antenna than what it really is. There is no way to protect the coil / spring as this is how they come from the factory I think I might need to buy a new antenna that's fibreglass as this design is like from the 70's thanks for your reply PS here is a pic of the antenna I have this one is brand new and in a lot better condition than mine but the way I see it is there is no way to protect the coil from rain

 

[mmckenna]

Get a plastic tupperware type bowl, cut a hole in it the same diameter as the antenna whip at the base. Slide it over the top and seal around the edges.
That should help protect it.

But a new antenna would solve that, too. Depends on your budget.

 

[smipe2001]

thanks for reply yea im only a pensioner lol so maybe one day when i have money i will get a imax2000 or a A99 this old girl that i have still makes a great antenna for my communications receiver. i only use the cb when the skip rolls in and even then i dont get out much on the 10 watts my old uniden ax 144 does. i will try to figer out a way to protect the coil. ive been reading up on these antennas and aprantly they act the same as a dipole. as my one is not earthed at all it it on a j pole bolted in the roof of the carport and no contact to ground. i read that the coax acts as a ground like the other half of a dipole. so im wondering if its still radiating omi directional. this would answer why when i key down i hear my voice through all the speakers in my house lol.

 

[KC4RAF]

The Tupperware tip that MMCKENNA suggested is a wonderful way to stop the rain or snow from getting in and on the coil and tap point. And you can get some paint that's rated for plastic/rubber, and paint it to match the antenna!