700-900 Mhz Cantenna

AB5ID

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Aug 6, 2007
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Lee's Summit, MO (Kansas City)
Wanting rejection to fend off P25 simulcast distortion, I thought I would check out what it takes to build a cantenna for 800Mhz, based on online calculators 10" seems to be a sweet spot for a 700-900 Mhz cantenna.
This seems like a good candidate for the "can".
https://www.lowes.com/pd/IMPERIAL-10-in-x-24-in-Galvanized-Steel-Round-Duct-Pipe/3286126

How to build your own WaveGuide Antenna (Cantenna) for 802.11b/g WiFi Wireless Networking and other 2.4GHz Applications - JEFA Tech
Another calculator:
Cantenna Calculator

I need to find a way to seal the back. I can't find any specifications on what kind gain out the front and more importantly, what of rejection to expect to the sides and back.
Has anyone tried this with any success?
 

prcguy

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Jun 30, 2006
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So Cal - Richardson, TX - Tewksbury, MA
What direction from the main signal source are you trying to eliminate? How many dB down do you need to reduce the offending signal? All directional antennas have sidelobes, even huge satellite dishes. On a $5mil satellite antenna the first sidelobes are only about 15dB down at best but successive sidelobes get better and better. I've seen corner reflectors with front to back specs ranging from low 20s to 30dB. They will still pick up stuff off the sides to some extent.

I wonder if I would be better off with a corner reflector type of antenna?
 

iMONITOR

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MACOMB, MI.
I wonder if I would be better off with a corner reflector type of antenna?
I tried an expensive commercial grade corner reflector and was not as directional as I anticipated.

Have you tried using attenuation or minimizing your antenna?
 

AB5ID

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Joined
Aug 6, 2007
Messages
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Location
Lee's Summit, MO (Kansas City)
I tried an expensive commercial grade corner reflector and was not as directional as I anticipated.

Have you tried using attenuation or minimizing your antenna?
I've tried a SMA decade step attenuator made for the microwave range (borrowed) to no avail. The best improvement came from a inexpensive indoor yagi from Amazon.
 

iMONITOR

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I've tried a SMA decade step attenuator made for the microwave range (borrowed) to no avail. The best improvement came from a inexpensive indoor yagi from Amazon.
Christmas is coming...time for a SDS100 or 200? :)
 
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