J-Pole Ladder Line Questions
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| Mar 2nd 2015, 17:25 | |
KK4ZLTTotal Topics: 0 Total Posts: 0 |
I am considering setting up this kind of antenna in our second floor office area, based on the instructions from "Build a Weatherproof PVC j-Pole Antenna" in ARRL's "Simple and Fun Antennas." I plan on 2 different antennas, 50m and 2m. The length for 50m is around 160 inches and the length for 2m about 55 inches. Can I install these horizontally along the edge where a wall meets the ceiling? How will the height above the ground for this second floor install effect performance, it at all? How far apart should they be? Will an antenna turner near my Yeasu 8900 help? Thank you all for your help! |
| Mar 2nd 2015, 18:04 | |
W1VTSuper Moderator Total Topics: 0 Total Posts: 0 |
2M FM is almost entirely vertically polarized--the most common exception are satellite transmissions. Mounting it horizontally would result in cross polarization to normal 2M FM transmissions, resulting in a large loss in signal. You are also likely to see a detuning effect from mounting it close to building materials. The antenna tuner isn't likely to help--tuners are much harder to build at VHF as compared with HF, so they aren't as common. Also, the higher line losses at VHF make them much less effective than at HF. Zack Lau W1VT ARRL Senior Lab Engineer |
| Mar 2nd 2015, 20:39 | |
KK4ZLTTotal Topics: 0 Total Posts: 0 |
You may can tell this is my first antenna attempt. Thank you for the help. No horizontal 2M antenna. Would the horizontal work with the 50M setup I described or would the same problems be present? |
| Mar 2nd 2015, 21:20 | |
W1VTSuper Moderator Total Topics: 0 Total Posts: 0 |
You sometimes get Sporadic E skip propagation on 52MHz, which converts the linear polarization into elliptical polarization, which would be compatible with a horizontally polarized J Pole. http://en.wikipedia.org/wiki/Sporadic_E_propagation http://forums.radioreference.com/amateur-radio-general-discussion/268257-lets-talk-about-6m-fm.html discussion of 6M activity Zack Lau W1VT ARRL Senior Lab Engineer |
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