1. You can now help support WorldwideDX when you shop on Amazon at no additional cost to you! Simply follow this Shop on Amazon link first and a portion of any purchase is sent to WorldwideDX to help with site costs.
    Dismiss Notice
Dismiss Notice
This forum does not allow a single user to have more than one username. If anyone wants to change their username contact an admin and it will be done. Multiple accounts belonging to the same member will be deleted without warning.

2-Meter Vertical Dipole

Discussion in 'Home Brew' started by T23, Jan 26, 2011.

  1. T23

    T23 Active Member

    Joined:
    Apr 17, 2010
    Messages:
    645
    Likes Received:
    10
    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
     

  2. kd-5-bgt

    kd-5-bgt W9WDX Amateur Radio Club Member

    Joined:
    Nov 10, 2007
    Messages:
    1,177
    Likes Received:
    89
    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....
     
  3. Moleculo

    Moleculo Administrator
    Staff Member

    Joined:
    Apr 14, 2002
    Messages:
    8,898
    Likes Received:
    1,055
    Is the SWR 1:2 or 2:1?
     
  4. T23

    T23 Active Member

    Joined:
    Apr 17, 2010
    Messages:
    645
    Likes Received:
    10
    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
     
  5. 15minigrass

    15minigrass Active Member

    Joined:
    Oct 30, 2006
    Messages:
    916
    Likes Received:
    23
    Is the Icom working for ya T23? I never really TX'ed on it due to not having my license.
     
  6. Moleculo

    Moleculo Administrator
    Staff Member

    Joined:
    Apr 14, 2002
    Messages:
    8,898
    Likes Received:
    1,055
    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.


     
  7. T23

    T23 Active Member

    Joined:
    Apr 17, 2010
    Messages:
    645
    Likes Received:
    10
    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
     
  8. Captain Kilowatt

    Captain Kilowatt Professional Amateur
    Staff Member

    Joined:
    Apr 6, 2005
    Messages:
    16,611
    Likes Received:
    10,389
    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.


    [​IMG]
     
  9. kd-5-bgt

    kd-5-bgt W9WDX Amateur Radio Club Member

    Joined:
    Nov 10, 2007
    Messages:
    1,177
    Likes Received:
    89
    Hey Captain that is a nice stand you have that meter sitting on :D ;)
     
  10. Captain Kilowatt

    Captain Kilowatt Professional Amateur
    Staff Member

    Joined:
    Apr 6, 2005
    Messages:
    16,611
    Likes Received:
    10,389

    I wish but unfortunately it's just a pix I found on the net. :cry:
     
  11. T23

    T23 Active Member

    Joined:
    Apr 17, 2010
    Messages:
    645
    Likes Received:
    10
    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
     

Share This Page

  • About Us

    The WorldwideDX Radio Forum was originally established in 2001. We pride ourselves on welcoming Radio Hobby enthusiasts of all types, while offering unbiased, informative, and friendly discussion among the members. We are working every day to make sure our community is the best Radio Hobbyist's site.
  • Like us on Facebook

  • Premium VIP Member

    The management works very hard to make sure the community is running the best software, best designs, and all the other bells and whistles. Care to buy us a beer? We'd really appreciate it!

    Donate to us!