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2-Meter Vertical Dipole

T23

Active Member
Apr 17, 2010
645
12
28
I have built a 2-Meter Vertical Dipole antenna but I am having some issues with the SWR, eatch length of wire coming from the shield and the center of the coax I cut to 20 inches ( I got this number from an article for building a 2-Meter dipole ) but when I check the SWR I can't get it to go below 1:2 , I had a test dipole that I trimmed to the same length and keep trimming until the SWR go to 2 aswell but I still couldn't get the SWR low enough. When I trimmed it shorter the SWR went back up to 3?

Whats up with that? :headbang
T23
 

I could be wrong ( and I usually am ) ...from what I can figure is the antenna was a bit to short to begin with....add a couple of inches to each side of the dipole and see what happens....it is alot easier to cut that couple of inches than try to add the couple of inches....
 
I got the SWR to a perfect 1:1 now it was 2:1 and consistent on both the test and final antenna.

But now I have another problem.... The SWR meters I am using, one work fine (which is an Astatic PDC7 ) And the other one is just showin a freak reading ( This one is the current radioshack 20w, 200w and 2KW SWR and watt meter combo )

T23
 
The problem is that the radio shack meter is only rated to 30Mhz. You're waaaay out of it's frequency range. You're probably out of the range for the PDC7 also, but if it's calibrating, you can probably get away with it. You need to get an SWR/Power meter that is for VHF/UHF, not CB.


I got the SWR to a perfect 1:1 now it was 2:1 and consistent on both the test and final antenna.

But now I have another problem.... The SWR meters I am using, one work fine (which is an Astatic PDC7 ) And the other one is just showin a freak reading ( This one is the current radioshack 20w, 200w and 2KW SWR and watt meter combo )

T23
 
Yea, I thought about that, but when I took apart a defective SWR meter before there wasn't really that much to it to be frequency specific, it looks like to me they just change the pot in there for more or less resistance when calabrating to make it easier ...

And yes, 15minigrass the Icom IC-230 works fine.


T23
 
Yea, I thought about that, but when I took apart a defective SWR meter before there wasn't really that much to it to be frequency specific, it looks like to me they just change the pot in there for more or less resistance when calabrating to make it easier ...

And yes, 15minigrass the Icom IC-230 works fine.


T23

Actually the entire physical design of the meter means a lot in determining the frequency range it will be accurate at. Typical CB meters that have a small circuit board with circuit traces as the pick up are not good at all for maintaining accuracy into the VHF or UHF range. Meters that use toroids as the pickup are only good for the range that the toroid material is good for. The better meters that cover a wide range of frequencies often have a band switch that selects different pick ups that are tuned specifically to be accurate over a certain range of frequencies. I have a Diamond SX-1000 that is good from 1.8 MHz to over 1.3 GHz but switches bands to maintain accuracy. It has two different inputs, one for HF to 160 MHz and another for above 160 MHz.


282635.jpg
 
I think I am just going to get a proper SWR meter for 2 Meters.... The PDC7 showed a low SWR of 1:1 so it should atleast be within working limits when I check the antenna with a proper meter.


Thanks

T23
 

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