mobile antenna to base !

[Grinder74]

Marconi, i used the same ant bracket but I put a "C" shaped piece of steel between the ant and the bracket and mounted 2 opposing 102's on the "C". Works great and is indestructable.

 

[medic18d]

it's about a k40 http://ecx.images-amazon.com/images/I/31Vt4Q6R23L._SY300_.jpg !!
citizen band
i just want to have the best results
thanks !!

sure but you need to set the magnet on a large piece of metal ...
even a cake pan, gutter and make sure to go as high as you can
but an antron 99 is actually cheaper than a k40

 

[222DBFL]

Yes sir, had my k40 on a 2ft x 2ft 1/4" steel plate, I also put 2 ground rods in and grounded the plate. The k40 did okay. It's not a real spectacular mobile antenna IMO. Had one and it worked okay, but no where near the performance of my sirio 5000. I would do like others have suggested and get a real base antenna or a dipole. You can get a dipole off eBay for pretty cheap these days. Have a look around. I think you can get them shipped for under 20 dollars and it will definitely work Better than the k40 IMO.

 

[triple5usb]

or make one. good fun work well and can be super cheap.

 

[stathis]

president jacson problem :\

i have a president jacson i found it in my garage and i is about 10 watt an when i am talking i goes up to 20 but the s meter is not working can i fix it ??

 

[stathis]

or where can i find an other one for replace

 

[johnny9]

like 22 said..and i have done myself months back till i upgraded..
i got a dipole wire thing from ebay for 11.99 free shipping..put it 24 ft high on a aluminum tube with no guy wires except the string used to pull the wires where i wanted them..
with that wire i talked 7,000 miles and talked many many places in the usa pretty easy..so easy it got me in gear to get a tower,then another antenna,then made my own 2 elemnt quad..still workin on it all..

look on here for wire antenna lengths and make your own for pennies if you have 12-14 ga copper wire,welding wire or ?? be creative,and have fun,j9

 

[hotrod]

its been 20 plus yrs since ive owned a k40 . but for some reason i was thinking this antenna
reccommended a certain lenth of coax.which really makes no sense . so i could be wrong
on this.i really dont undestand how adding coax lenth increased his swr.especially by
that much.sorry im a little lost on this one

 

[M0GVZ]

i really dont undestand how adding coax lenth increased his swr.especially by
that much.sorry im a little lost on this one

In simple terms...
The antenna is actually part of a system. Current flowing into an antenna needs to return to the source. An end fed antenna like a CB mobile vertical is effectly only half an antenna so you need to make up the missing half to allow the current to return to the source which is usually the body of the car.

When you have a piss poor ground the antenna system uses anything it can to make up the missing half and this is usually the coax. So effectively what you have is a dipole with one half of the dipole being the CB whip, the other half being the coax. When you alter the length of the coax from being a quarter wavelength or multiple thereof, it alters the tuning and alters the SWR.

Now if it was a properly installed antenna with a good ground plane then you can use any length you want and it shouldn't make any difference.

 

[222DBFL]

Yep properly grounded I showed a better VSWR reading with the k40 mounted to a 2ft x 2ft x 1/4" plate with a #10awg solid ground, I also used a barrel connector and 50ft of lmr240. My swr reading did not change with the added coax. Good ground and a good ground plane will do wonders. It wasn't anything spectacular and I had better luck with a homemade dipole!! You can purchase a very good dipole for less than the cost of a k40. They are very easy to make as well. A good dipole setup to around 30ft got me around the world with a stock uniden pc122xl. But the k40 will work for local talk just fine, just don't expect any miracles with it.

 

[stathis]

hello !! yesterday i made a dipole , i tune it my swr about 1.1 it works well my range about 4000 miles my question is can i use an amp on the dipole ??
i also lent the k40 to my friend kai my old cb and it didn t work well here is the set up of my friend yard !

 

[stathis]

and this are the swr and tx are on the ather post up !

 

[stathis]

swr

 

[jazzsinger]

You can use any mobile antenna as a base, best idea is to get it mouted on top of a 20 ft + pole, then add 3 or 4 evenly spaced wires about 108" in length at approx 40-45 degree angle.to the ground side of the mount,

then trim each equally in small amounts to get best swr, will work almost as well as a Starduster m400.

for the last time because i'm sick of saying it, please stop recommending 102" whips, they are too short for any cb frequency between 26 and 28 mhz, they are more suited to the 10m band. cb whips vary from about 103" to 107" when resonant depending on where you set centre frequency for. thats the reason most people need a shorted spring to resonate them.

this myth is almost as bad as A99 9.9Dbi gain. I've showed the maths time and time again for this, and even if The DB is right and I wrongly use the .98 velocity factor instead of no velocity factor which he supports, that would make them even longer when resonant and 102 " whips even shorter than they should be. :bdh::bdh::bdh:

 

[w9cll]

for the last time because i'm sick of saying it, please stop recommending 102" whips, they are too short for any cb frequency between 26 and 28 mhz, they are more suited to the 10m band. cb whips vary from about 103" to 107" when resonant depending on where you set centre frequency for. thats the reason most people need a shorted spring to resonate them.

this myth is almost as bad as A99 9.9Dbi gain. I've showed the maths time and time again for this, and even if The DB is right and I wrongly use the .98 velocity factor instead of no velocity factor which he supports, that would make them even longer when resonant and 102 " whips even shorter than they should be. :bdh::bdh::bdh:

Then don't say it anymore..

No seriously the whips are sold here in the "102" length and that is where the problem lies. Yes I agree you need longer for 11 meters, this is where the spring comes into play.