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cobra 29 LTD and an 11 meter dipole

hmm, as far as grounding goes. I'm using a power converter that plugs into the wall outlet, and my radio sits on top of it, and plugs the 12 volt positive and neg into it. I don't have any other grounding straps or lines attached... should I? I did try using the built in SWR meter on the radio and tried adjsuting my SWR according to the radios guide. I dialed the SWR tune knob to the CAL line, then switches back from cal to swr. My swr needle only went down a little bit, it's still up in the red. Would this mean I need to shorten or lenthen my existing dipole? Not exactly sure how I go about reducing my SWR? I think I'll stop by bookis a million tomorrow at lunch... any recommendations on a good book for a beginner? Also, I read about the different bands, 2 meter, 10 meter, 17 meter. Do folks have to have a different antenna for each band? (I assume so) If that's the case, do most folks just pick a band they want to play with (like 10 meter) and just start working and talking to other folks on the ten meter setup? What's the most popular bands? Are dif bands used for dif functions?

Obviously I have questions. I think It'd be real kewl to be able to kick back and talk to folks around the state, or country, or world... I'm ready for some baby steps. Just looking for some good, honest feedback from folks that've already gone through the learning stage...

Thanks again everyone!!!!
 
deadhead said:
hmm, as far as grounding goes. I'm using a power converter that plugs into the wall outlet, and my radio sits on top of it, and plugs the 12 volt positive and neg into it. I don't have any other grounding straps or lines attached... should I? I did try using the built in SWR meter on the radio and tried adjsuting my SWR according to the radios guide. I dialed the SWR tune knob to the CAL line, then switches back from cal to swr. My swr needle only went down a little bit, it's still up in the red. Would this mean I need to shorten or lenthen my existing dipole? Not exactly sure how I go about reducing my SWR? I think I'll stop by bookis a million tomorrow at lunch... any recommendations on a good book for a beginner? Also, I read about the different bands, 2 meter, 10 meter, 17 meter. Do folks have to have a different antenna for each band? (I assume so) If that's the case, do most folks just pick a band they want to play with (like 10 meter) and just start working and talking to other folks on the ten meter setup? What's the most popular bands? Are dif bands used for dif functions?

Obviously I have questions. I think It'd be real kewl to be able to kick back and talk to folks around the state, or country, or world... I'm ready for some baby steps. Just looking for some good, honest feedback from folks that've already gone through the learning stage...

Thanks again everyone!!!!
Click to expand...

Happy to help.

With the different bands you will need diferent lengths dipoles. There are people who have made multiple band Dipoles.

As far as adjusting your SWR. Simply folding the wire back on itself will do this for you. You can cut if you wish but not necassary. I posted a link to a Dipole calculator in one of my earlier posts. I used 27.185 MHZ in my calculation which is pretty darn close to center of the CB (11m) band. I got a length of 8.61 feet for each leg of your Dipole and an over all length of 17.2 feet.


Keep asking away we love questions here.
 
I dialed the SWR tune knob to the CAL line, then switches back from cal to swr. My swr needle only went down a little bit, it's still up in the red. Would this mean I need to shorten or lenthen my existing dipole?
Click to expand...

Here is a simple way to see if you need to go longer, or shorter.
Check the SWR, just the way you did.
Check it on channel 1
Write the result down on paper ( the meter on swr reads 1 then 2 then 3)
Check it on ch 20
Write it down
check it on 40
Write it down.
Make sure you set it to the Cal mark each time you do this.
Look at the resulting numbers.

If you have higher numbers on channel 1 than channel 40 , your antenna needs to be shorter.
if you have higher numbers on channel 40 than channel 1 then your antenna
needs to be longer.

The Ideal numbers would be lowest on channel 20, with a slight rise on 40 and a slight rise on channel 1.
An example would be
1.3 on channel 20 and about 1.7 on channel 40 and channel 1

the rule of thumb is
Longer antennas work lower in frequency
shorter antennas work higher in frequency
this is one way to tell where you are with the length of the antenna if everything else ( coax, connectors, reflect from nearby metal,etc ) is OK.
And as S/D said, folding the wire back on it`s self is good.
try this and let us know what you get as the result.

73
Jeff
 
got home from work and my 3 range power/modulation/SWR tester is here... woohoo!! but it's raining and lightening, so I'm not going to be going up and down the ladder adjusting my antenna tonight. Hopefully tomorrow.
 
Success!!! I think. :)
You guys tell me. I've been back and forth to the attick adjusting the length of my dipole. I think I've got it in the sweet spot right at 93 inches on each side of the dipole. Channel-1 =1.6swr, channel-20 =1.4swr, and channel-40 =1.3swr. Sound good to you guys?

Oh yea, when I started getting close with the length needed, my antenna warning light went off and stayed off.

Next Question: Can I take a couple pieces of 93" wire and make the same dipole both vertical and horizontal? Or would a couple of 93" pieces below the dipole angled at at 45degrees give me more range by providing ground plane scenario? Basically, how can I improve my existing dipole antenna range? Or should I leave it like it is?

I went and picked up Ham Radio for dummies, so I'm starting read up a bit.

Hopefully One day I'll be able to communicate intelegently concerning radio technology.

:)
 
Last edited:
k, I added one 45 degree angle piece of 93" copper to my dipole as a test, and now I'm getting:

Ch-1=1.2swr
Ch-20=1.2swr
Ch-40=1.3swr

Does that make it a "tri-Pole"?
My power meter reads at about 7 watts, Am I heading in the right direction??
 
deadhead said:
k, I added one 45 degree angle piece of 93" copper to my dipole as a test, and now I'm getting:

Ch-1=1.2swr
Ch-20=1.2swr
Ch-40=1.3swr

Does that make it a "tri-Pole"?
My power meter reads at about 7 watts, Am I heading in the right direction??
Click to expand...

That makes it a dipole that simulates a very large conductor diameter. It may or may not help your signal.

SWR alone is only an indication of impedance matching.

Are there parallel wires nearby the antenna in the attice?

What is your roof made of? Tile can have conductinve minerals in it that will affect your signal. A foil vapor barrier can sheild off you antenna entirely.

In addition to the SWR, how is the antenna performing?

Can you hear anyone?

Can they hear you?

Dave_W6DPS
 

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