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Joey_migs
Junior Member
Username: Joey_migs
Post Number: 26
Registered: 9-2009
| | Posted on Saturday, October 03, 2009 - 12:57 am: | 
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I am trying to construct a 11 meter dipole.
I made a 1.5:1 transformer (to better match the 72 ohms dipole feed to the 50 ohms transceiver _ like the an effectiveness ant possible.I want the feedline matched the feedpoint of ant, and 1:1 SWR at the base into the coax. I used a FT-240-61 ferrite toroid, a trifilar winding of no. 14 enamel coated copper wire and a couple of capacitors. I tested the setup using a RG-8 to transformer to RG-59 terminated with a 72 ohm dummy load - the SWR was less than 1.3:1 across the band.
My question is the dipole is balanced and the coax is unbalanced will this cause any problems?
Can I just loop the coax coming from bottom of the ANT> 4~5 times around a 2 inch PVC pipe (as a choke) to impede the current from riding the braiding of the coax. i am i right?
Thx, Miggs |
Tech237
Moderator
Username: Tech237
Post Number: 1230
Registered: 4-2004
| | Posted on Saturday, October 03, 2009 - 2:24 pm: |
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Joey - please see then answer to your prior question, as the answers remain the same. A coaxial choke at 11m needs to be around 6" diameter to have the best chance of working correctly, and at least 2-3 turns.
As I mentioned last time, throw the "transformer" away, as it is really two tuned circuits and is NOT giving you an accurate reading on the SWR of your antenna, and either run straight to the antenna with a coax choke, or insert a proper 1:1 balun inline.
Simon
Tech237
N7AUS
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I thought he said, "there was no rust for the wicked, and I own an MGB"
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Joey_migs
Junior Member
Username: Joey_migs
Post Number: 28
Registered: 9-2009
| | Posted on Sunday, October 04, 2009 - 12:24 pm: |
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Got you, Thanks
Joe |
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