DirecWay Antenna

h3brewing · EVDO Newbie Joined: 06 Nov 2007 Posts: 8 Location: KC, MO

I am just checking to see if anyone has successfully modded an old DirecWay receiver / transmitter dish into an EV-DO antenna? I am currently about 9.5 miles away from the nearest tower and with an existing amp and a 7db inside / outside antenna I am getting around 98 - 92 db signal and at best 300 to 500k downloads. I found an old direcway dish that my neighbor was removing and picked it up in the hopes of creating a decent antenna. I know some have created dish antenna's on here before, but has anyone done it with a direcway dish and if so did you do a bi-quad / double bi-quad as your element? I took the dish and just set it on my deck last night, strapped my 7db antenna to it and pointed it at the dish and I saw my signal drop to 77 db, tried out the download and I was hovering around 990k. That is a vast improvement. Any suggestions on design or experiences would be greatly appreciated.

xrayman · Posted: Tue Nov 06, 2007 9:07 am Post subject:

Did you see this setup?

http://www.evdoforums.com/viewtopic.php?t=2879&highlight=

http://www.evdoforums.com/thread7117.html&highlight=

shooter64738 · EVDO User Joined: 07 Sep 2007 Posts: 41

I built this one a few months back. It's been working well. I've tweaked and fiddle with it until I got my signal down into the upper 60's (-69db right now) It was in the upper 90's/ low 100's when I started. It uses a dual band Bi-Quad feed.

h3brewing · EVDO Newbie Joined: 06 Nov 2007 Posts: 8 Location: KC, MO

I did, I just didn't know if it would be about the same or different with a direcway dish since it is oblong? I am going to play with it some more over the week and see if I can refine it. I will post pics when I am done. Thanks

shooter64738 · EVDO User Joined: 07 Sep 2007 Posts: 41

It's an offset feed dish. Just put your feed in the same location as the original feed point, and it should still focus it satisfactory for you. Keep in mind the dish will need to be pointed in what would appear to be a 'downward' angle, since you are picking up a terrestrial signal, instead of a satelite signal. The bigger the dish the better. I've been trying to get my hands on an old style 5 foot dish, so I can get the neighbors on an evdo connection.

I think a simple dipole feed would work, but the dual band bi-quad really has helped improve the uplaod as well as the download speeds, so I'm gonna stick with that. Aiming will take a little time, but it's been well worth it in my case. I do wish now I had gotta a router and the pcmcia modem though, so I wouldn't have to have this blasted coax.

h3brewing · EVDO Newbie Joined: 06 Nov 2007 Posts: 8 Location: KC, MO

Thanks for you advice shooter and xrayman. I am going to give a shot at building the double biquad tonight and hopefully have it all setup before Thursday as I have to work from home Thursday and Friday. In the past its been painful doing work from home as I am usually parsing several logs at once and anything over three production logs and I was choking. I think I am just going to leave the router and amp out underneath the covered deck and do a make shift cover until I can get some decent coax and run the router down into the basement. Thanks again for your help.

shooter64738 · EVDO User Joined: 07 Sep 2007 Posts: 41

Just to clarify I did not build a dual biquad. I built a single bi quad that supports dual bands. I have seen the double dual band bi-quads, but I have not tried one of those, and my setup doesn't include one. The doubles may work better, but I don't have any numbers to point you to for reference.

Good luck though!

n6gn · Posted: Tue Nov 06, 2007 10:38 am Post subject:

Just a note:
When picking a feed for a dish, realize that there is an optimum design between too-low and too-high gain.

If the feed antenna is too directive, the outer portions of the dish are not illuminated by the feed are wasted. The resulting antenna will work, but not as well as one with a smaller, lower gain feed.

If the feed antenna is not directive enough, particularly possible on flatter dishes with a lower Focal length/Diameter (F/D) ratio, then some of the energy from the feed goes past the outer edge of the reflector and is wasted, Again the resulting antenna will work but not as well as one with a somewhat larger (electrically), higher gain feed.

Good feed design is quite complicated and a given feed is only optimum for one particular dish.

This isn't to discourage anyone, just don't assume that an antenna that works better without a dish reflector will work better when used as a feed. For common dish F/Ds, often under 0.5, a dipole/reflector or equivalent may be the best simple approach.

n6gn

n6gn

dondrm · EVDO User Joined: 06 Sep 2007 Posts: 64

shooter64738 · EVDO User Joined: 07 Sep 2007 Posts: 41

h3brewing · EVDO Newbie Joined: 06 Nov 2007 Posts: 8 Location: KC, MO

I did some preliminary testing with the dish and here is what I came up with. I went from approximately 88 to 92 dbm to around the 63 to 67 dbm mark with the dish setup. my downloads improved from around 350K to about 1351 down now. all I need to do now is move my router to the basement and attempt to make the biquad or not? Not really sure if I need it still as I am getting pretty decent speeds with the antenna that is mounted right now.

Here are some pics let me know what you think

for some reason I keep triggering the spam feature so I cant post any pics. PM me if you want to see them. Thanks for everyones help

budmanozzy · EVDO Newbie Joined: 08 Aug 2007 Posts: 2

Hi, I would love to see your setup. I tried to pm you for the pics, but for some reason it says I can't send a pm.

Thanks

h3brewing · EVDO Newbie Joined: 06 Nov 2007 Posts: 8 Location: KC, MO

Here is another shot at my setup

Front

http://i213.photobucket.com/albums/cc215/h3brewing/img003.jpg

Back

http://i213.photobucket.com/albums/cc215/h3brewing/img004-1.jpg

Results

http://i213.photobucket.com/albums/cc215/h3brewing/khullspeedtest.jpg

turkeyhill00 · EVDO Fledgling Joined: 28 Nov 2007 Posts: 13

Hey, thanks for the pictures. I have both direcway and a wildblue dish. If you don't mind what all would I need to use one of these. And any instructions on how to hook it up.

Thanks

h3brewing · EVDO Newbie Joined: 06 Nov 2007 Posts: 8 Location: KC, MO

I basically just took the dish apart and removed all of the direcway feedhorn assembly. This was nice because it lightens up the dish considerably. Next I mounted the dish under one of the eaves of my wrap around deck in the direction of where I knew the tower to be. I setup the dish and basically just set it to shoot at the horizon. I mounted the 7db antenna where the feedhorn assembly used to be and routed the cable through the feedhorn arm. When mounting the antenna to the dish you are going to point the directional antenna at the middle of the dish. Next I mounted the amp to the back of the dish and then screwed the antenna cable into the cable port of the router. Then I powered up the amp and connected the output to the aircard and then fired up the laptop for tuning. Spent about fifteen minutes tuning it. Open up your connection manager software and fire it up. After your connected do the ##DEBUG whilst hovering over the connection bars. Once the debug panel pops then go set your refresh rate down to every second or 1000ms. I made slow sweeping movements until I got the general direction down of the tower. I just watched the db meter and basically worked it until I got my db down to like -63dbm. After that I played with the vertical articulation but it really didn't make much of a difference if any. I locked everything down then tested again to make sure I hadn't screwed anything up. After that I just made a simple hut for the router to sit inside and its been there now for a week or so. After I get some more time I am going to move the router down to my basement. Just need to get some time away from work to knock that last part out. Let me know if you have any more questions or if you need some more pics.

Tks in advance, H3