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 Subject :high gain antennas for Providence.. 2013-11-27- 21:08:52 
w9gyr
Member
Joined: 2013-06-25- 14:14:43
Posts: 20
Location: Rhode Island FN41gt
 

Thanks to Peter Harrison AA1PL for donating a pair of fine commercial parabolic reflectors to the cause. We'll be putting these to good use at our Providence nodes very soon.



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 2013-11-26 11.01.35.jpg [931 KB] :: antennas with cat for scale
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Last Edited On: 2013-11-27- 21:09:55 By w9gyr for the Reason
-mikeu W9GYR

Blog: http://fornaxchimiae.blogspot.com/
 Subject :Re:high gain antennas for Providence.. 2013-11-29- 22:54:22 
K5KTF
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Joined: 2010-01-18- 23:04:04
Posts: 266
Location: 5' from this webserver
  

FYI, I have converted a couple of these for mesh use.

If it has a downconverter (I see the familiar RG6 F connectors on the side), you will need to bypass it and run the coax straight to the dipole feed. The feeds are usually hermetically sealed and a dremel with fine cutoff wheel and a steady hand can get it open for modification.

Also, if they are the old "Wireless TV" antennas, you should check the dipole length (468/2412=0.1940, or 2.328"). The ones I found were a tad short (made for slightly higher freq's), so I flattened out some copper and soldered it on the dipole to get the correct length (verified by attaching to a high-dollar VNA for resonance/SWR at a corporate S.I. Lab).

They just do not seem to perform as well (even though the VNA says its good) as commercially available units made specifically for the low end of wifi. Nothing I can point a finger at, but I am suspicious of them, as they dont seem to be doing as well as the 'real' ones.

Just something to ponder.

KTF



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B-) Jim K5KTF EM10bm Cedar Park, TX :star:
 Subject :Re:high gain antennas for Providence.. 2013-11-30- 09:34:20 
w9gyr
Member
Joined: 2013-06-25- 14:14:43
Posts: 20
Location: Rhode Island FN41gt
 

Thanks for the info and advice. That may come in handy as we are salvaging a number of different type of antennas. These are commercial 2.4G (the number is stamped on the feed next to a barcode serial number) and I believe that they were formerly used for point-to-point extended wifi. It has Type N connectors with LMR-400 coax. We'll be testing them before installation to be sure.





[K5KTF 2013-11-29- 16:54:22]:

FYI, I have converted a couple of these for mesh use.

If it has a downconverter (I see the familiar RG6 F connectors on the side), you will need to bypass it and run the coax straight to the dipole feed. The feeds are usually hermetically sealed and a dremel with fine cutoff wheel and a steady hand can get it open for modification.

Also, if they are the old "Wireless TV" antennas, you should check the dipole length (468/2412=0.1940, or 2.328"). The ones I found were a tad short (made for slightly higher freq's), so I flattened out some copper and soldered it on the dipole to get the correct length (verified by attaching to a high-dollar VNA for resonance/SWR at a corporate S.I. Lab).

They just do not seem to perform as well (even though the VNA says its good) as commercially available units made specifically for the low end of wifi. Nothing I can point a finger at, but I am suspicious of them, as they dont seem to be doing as well as the 'real' ones.

Just something to ponder.

KTF






Attachments
 2013-11-30 10.18.44.jpg [623 KB] :: feed detail
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Last Edited On: 2013-11-30- 09:37:18 By w9gyr for the Reason attach image
-mikeu W9GYR

Blog: http://fornaxchimiae.blogspot.com/
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