M105
Member
- Joined
- Sep 13, 2005
- Messages
- 399
I was introduced to the Moxon antenna at an amateur radio club recently. Since I had been looking around for an easy to build directional antenna to monitor the local 770 MHz P25 system I decided to run the numbers for 772Mhz and see how big the antenna would be. It turned out to be small enough to sit on my desktop at about 3x7 inches. There are two nice calculators on the web.
Moxon Calculator
W4/VP9KF - Online Moxon calculator
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I built the antenna in the attached images using some plastic cardboard material like the political yard signs are made of. A block of wood with a slot cut in it serves as the base. The elements are made from a length of #12 copper wire (2.05 mm diameter) connected to an F type chassis mount coax connector. The wire is held in place with hot glue.
I have no equipment to test this antenna for SWR at this frequency so my performance report is anecdotal to be honest. I can say that it works better than I expected and gives me a better signal according to DSD+ sitting indoors on my desk than does my outdoor folded dipole cut for the same frequency. It is directional but not a sharp beam so aiming isn't critical. I use a TV splitter to send the signal to two SDR dongles.
Anyway so I offer it here for those of you who like to experiment. It is a quick and easy project that exceeded my expectations. If you are looking for an indoor or outdoor homebrew antenna this might be an option. I like it because I recently had lightning damage a computer with SDR dongles connected to an outdoor antenna. This one sits on the desk with a short connection to the dongles.
Moxon Calculator
W4/VP9KF - Online Moxon calculator
===================
I built the antenna in the attached images using some plastic cardboard material like the political yard signs are made of. A block of wood with a slot cut in it serves as the base. The elements are made from a length of #12 copper wire (2.05 mm diameter) connected to an F type chassis mount coax connector. The wire is held in place with hot glue.
I have no equipment to test this antenna for SWR at this frequency so my performance report is anecdotal to be honest. I can say that it works better than I expected and gives me a better signal according to DSD+ sitting indoors on my desk than does my outdoor folded dipole cut for the same frequency. It is directional but not a sharp beam so aiming isn't critical. I use a TV splitter to send the signal to two SDR dongles.
Anyway so I offer it here for those of you who like to experiment. It is a quick and easy project that exceeded my expectations. If you are looking for an indoor or outdoor homebrew antenna this might be an option. I like it because I recently had lightning damage a computer with SDR dongles connected to an outdoor antenna. This one sits on the desk with a short connection to the dongles.