Posted: 11/16/2014 2:06:28 PM EDT
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I'm trying to get 1 up on the competition. Fox hunting has become a Hard core event, for our club of late. I'm thinking of using a 6-8" tube covered in Foil, with a end cap. this will hopefully get a great deal of directionality. Since it is a receive only, How much larger than the receive element does it need to be? like mounting the factory antenna from a ft-60 inside the tube for the receive element. I'm not finding a good formula, regarding this part of the build.
Can anyone point me to a source? Thanks. |
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Build a steel tape measure / PVC Yagi. One I made this summer.
You can use 3rd harmonic to help once you get close in on the fox. Fox freq.mHz X 3 = 3rd Harmonic. (2m X 3= 70cm) Also change the polarization of the Yagi to reduce the effectiveness cutting 15dB - 20 dB. If your fox is typical FM vertical polarized putting the Yagi to horizontal polarized is like running an attenuator helping to cut the signal with a simple turn of the wrist. Your FT-60 has a great reception range good for all kinds of listening. Another option is to maybe consider getting a loop antenna. Something like this. If you have more that one HT try them all on a fox signal more than likely you will quickly find that some HTs have better reception circuitry than others. I use one radio for distance then switch to another for closer work. Another benefit of having a handheld Yagi. I have used my HT Yagi for distances where HT to HT would never make the connection. Hi-gain antenna HT to Hi-gain antenna HT both with the squelch open nothing could be heard. With just one Yagi in use we had perfect clear reception on both sides. Running both locations with Yagis would be ideal at that distance for real SHTF HT communications. |
| The problem I'm trying to over come, is that Yagis and loops have too WIDE of a "Field of View". In town they will give a very good reading on a reflected path. we have a great meter, but need to cut time in shielding against multiple reflections for comparison. We use the "National" fox hunt freq. 145.xx |
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Quoted:
Phase them I did that with two UHF yagi's…worked beautifully. For anyone wondering on how to properly co-phase antennas, simply run an odd quarter wave length of 75 ohm coax (I used RG-59 with UHF reducers) from each antenna two a T and then 50 ohm out the T. Best results result in antennas 1 wave length apart. |
