building 800MHz antenna

[SCPD]

Does anyone know what I could build a 800MHz anntena out of I am tring to recieve a trunked system. I can recieve it on the rat shack 800 MHZ antenna inside but not very good.I bought the $25 scanner antenna from rat shack put it about 30 \ft. off the ground with worse luck. I think just building my own will be my best option. ( I'm a cheap bastard and build my own stuff alot) also what cable will work best for 800MHz

 

[K9GTJ]

http://www.pbase.com/dickh/image/27104369

 

[W4KRR]

Does anyone know what I could build a 800MHz anntena out of I am tring to recieve a trunked system. I can recieve it on the rat shack 800 MHZ antenna inside but not very good.I bought the $25 scanner antenna from rat shack put it about 30 \ft. off the ground with worse luck. I think just building my own will be my best option. ( I'm a cheap bastard and build my own stuff alot) also what cable will work best for 800MHz

What kind of coax cable did you originally use? (Please don't say "RG-58")

Best coax for 800 MHz would be a low loss cable like LMR400 or Belden 9913.

 

[SCPD]

800MHz

yes I tried RG58 also tried cheap cable tv cable. does rat shack have any low loss cable?

 

[SCPD]

I guess what ohm cable should I be using 50 or 75 . kokomo1 cool idea for antenna somthing I will try any way to make it directional or a way to make a dirctional I only need to point in one spot the only trunked plce close to me in the cornfields of WI

 

[W4KRR]

I guess what ohm cable should I be using 50 or 75 . kokomo1 cool idea for antenna somthing I will try any way to make it directional or a way to make a dirctional I only need to point in one spot the only trunked plce close to me in the cornfields of WI

I would do a Google search for "Belden 9913 coax" or "LMR400 coax" and buy it from a dealer that deals in coax cable.

You can use RG-6U 75 ohm coax for receiving, it's better than RG-58, but the quality of the Radio Shack stuff is questionable. The impedance (ohms) isn't as important for receive only setups as it is for transmitting. Low loss is what's important, especially at 800 MHz frequencies.

 

[acarsnut]

I have built a couple 800 mhz yagi's useing this web site.Has a nice program right on the page.Just enter freq.And it also shows how to feed it.very nice site.




http://www.k7mem.150m.com/Electronic_Notebook/antennas/yagi_vhf.html

 

[Skypilot007]

I built one of these tuned 506MHz. I used 9913 coax but will use something else next time. Something with a copper sheild. It works very well. I'm planning on another one for 860MHz when I get time. Its a bit teadious to build and being good with a solder iron helps a lot.

http://wireless.gumph.org/articles/homemadeomni.html

 

[scanbob]

mounting

http://www.pbase.com/dickh/image/27104369

That is a neat little unit. How do you mount it , can you hang it buy a nylon fishing line or somthing non conductive?

 

[73cuda]

I have built a couple 800 mhz yagi's useing this web site.Has a nice program right on the page.Just enter freq.And it also shows how to feed it.very nice site.




Martin E. Meserve - K7MEM - VHF/UHF Yagi Antenna Design

I know this is an old thread but I'm going to be building a 850 mhz yagi with a metal boom and have a couple of questions please.

The reflector and directors make direct contact with the boom correct ?

Both the driven elements are insulated from the boom ?

And that's a great link for designing yagis !

Thanks

 

[tactcom42]

on that page where you enter the freq look for this area.you pick if you want insulated or connected boom.and over on the left side of page go to yagi quick feed and see how to do the driven element.

 

[k8tmk]

The article in Pop Comm, May 2007 shows three designs for an 800 MHz yagi. I built the 10-element one which works great. It was easy to build, requires minimal tools to build, and all parts can be obtained for pocket change. I used 9913 coaxial cable and mounted it to the side of a TV tower about 40 feet up.

Randy, K8TMK

 

[73cuda]

on that page where you enter the freq look for this area.you pick if you want insulated or connected boom.and over on the left side of page go to yagi quick feed and see how to do the driven element.

I didn't know that's what insulated meant in this case but that makes sense now. I'll go back and take a closer look.

k8tmk, I'm very interested in that but I don't have access to the full article.

Thanks much !

 

[73cuda]

Okay, I've decided to do metal boom insulated. The boom will be 3/4" "U" channel with plastic sleeves for the 1/8" diameter elements to go through. I think using the 300 ohm balun will be the best choice for me. I know the elements all need to be on the same line and will not use a plastic box for the driven elements as shown. What do you guys think about that plan ?

Thanks !

 

[73cuda]

Here's the 850mhz, 12 db gain design from that great site...

 

[w2xq]

Ground Plane photo - Dick Harris photos at pbase.com

That photo is worth a few thousand words. Can't get any simpler to make a home-brew antenna. I have made several of these groundplanes over the years, for ham bands and PSB, I usually use wire coat hangers; just clean the paint off the end attached to the SO-239. Attach a lightweight cord to the vertical element and toss the cord over a tree branch.