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half wave sleeve dipole antenna

 
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half wave sleeve dipole antenna
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nickone
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Joined: 03 Dec 2013
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Post half wave sleeve dipole antenna Reply with quote
hi
- can i ask - i purchased this antenna - low power half wave sleeve - on the site it says to change the plug for more power - im running 15 watts into it.. i have changed to a so239.. the packaging suggests that this antenna is 75 ohm not 50ohm.. can i ask will changing the plug do the job or do i also need to change the looped up coax inside the plastic head unit - as is this 75 ohm coax ? also do you have a cutting chart for this antenna - as its shows me rather high swr accross the band.. i wanted to run low power into it ..

thanks nick
Tue Dec 03, 2013 4:05 pm View user's profile Send private message
pcs
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Location: Radio Land

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Back in the 50's when tube transmitters had built-in pi-net outputs, many hams used 75 ohm cables like RG-11. In actual practice, there is little difference in efficiency with an indicated SWR of 1.5:1. This is negligible.

http://forums.qrz.com/showthread.php?179802-75-ohm-cable-mismatch-question

This particular antenna is perfect for small transmitters. The size and method od mounting make it very practical. It is also very cheap. It was recommended to me by an engineer of our national TV/Radio.

A bit of SWR is not a problem at low power. This is why this is for low power applications and receive applications only.

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Fri Dec 20, 2013 2:45 pm View user's profile Send private message Visit poster's website
nickone
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Post Reply with quote
thanks -
yes agree - ive now since set it up in a clearer space - and run 4-5 watts through, with just the so239 modification using 50ohm rg58 coax to tx..swr meter seems happier..
thanks
Sun Dec 22, 2013 2:34 pm View user's profile Send private message
pcs
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Its happiest with some metal under it, metal roof probably the best choice.

_________________
Best regards,
Marko - PCS Electronics
--------------------------------------------------------
Turn your PC into a FM radio station!
http://www.pcs-electronics.com
fax +386 4 2316 128
Sun Dec 22, 2013 3:54 pm View user's profile Send private message Visit poster's website
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