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Resbum
Antenna-Theory.com Newbie

Joined: 22 Aug 2015
Posts: 3
Location: Off-grid Eastern Oregon, USA

 Posted: Sat Aug 22, 2015 12:51 am    Post subject: Can this be done? DIY dual frequency point to point biquad Hi All, my first post here. I live off-grid and I'm working at improving my wireless internet. I've pretty much settled on using an old satellite tv dish with a biquad head because this combo looks to have reasonable gain AND I have all the pieces to make it laying around. Verizon 4G LTE operates on both 700MHz and 1700MHz. After searching for the last three days I still haven't come up with a concrete answer to this. The theory for a biquad has the element for a given frequency an XXX length and XXX distance off the reflector. The online calculators say the distances off the reflector for 700MHz and 1700MHz are approx. 21mm and 40mm, if I remember correctly. I'm pretty brain smoked at this point. Is it feasible that you can make a 1/4 wave length element for each frequency, then stack them one on top of the other above the reflector at the given distance they're supposed to be? Physically it will all fit together based on the calculators. What I can't find an answer to is, "Will this work for actually transmitting and receiving efficiently?" Any help will be greatly appreciated. Resbum . .
helix
Antenna Theory Regular

Joined: 29 Jan 2015
Posts: 64

 Posted: Tue Sep 08, 2015 4:56 am    Post subject: I think the answer is "it depends". You need to do some design/modeling with a code like NEC or FEKO -- there is not a simple answer to your question. A question you have not asked is how to feed such a structure? Is this a coax feed or a twinline feed?
Resbum
Antenna-Theory.com Newbie

Joined: 22 Aug 2015
Posts: 3
Location: Off-grid Eastern Oregon, USA

Posted: Tue Sep 08, 2015 2:29 pm    Post subject:

 helix wrote: ... -- there is not a simple answer to your question. A question you have not asked is how to feed such a structure? Is this a coax feed or a twinline feed?

Thanks for the reply, helix.

To answer your second part first, I have about 70 feet of LMR400 and a female N type connector to feed the antenna.

As I was researching this I came to learn there are MANY things about antennas that don't have simple answers. In the two weeks since I posted this I've explored some options that seem to have a simpler answer to my needs.

antenna-theory.com has been a huge help in wrapping my head around antenna design.

Originally, I wanted to stay away from a general wide-band antenna to help isolate things down to just the freqs I wanted. However, this seems to be my best option with the limited resources I have to work with.

Again, thanks. Resbum
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