antenna clearence - Page 2

rerunn · 08-06-2002

Quote:

Originally posted by lincomatic
here is flickenger's analysis of cringe's passive repeater:

http://www.oreillynet.com/cs/user/view/wlg/1124

Uggh... I remember reading this way back then too! Maybe the fact that I didnt have any wireless gear at the time made me not pay attention.

Enough from me. Sorry for beating a dead horse.

sparafina · 08-06-2002

Yeah I watched his series on building a plane, so I'm not surprised if its a hoax.

systemd0wn · 08-06-2002

Ted,
aight, so what your saying is use the other tower (if both buildings have line of sight to it) as a passive repeater?
I wouldnt think that it would have enough surface area to create this effect. Then again, i dont know how much you need. Anyway, ill be checking out the line of sight tomarrow so we will see

thanks everyone!

lincomatic · 08-06-2002

Quote:

Originally posted by systemd0wn
Ted,
aight, so what your saying is use the other tower (if both buildings have line of sight to it) as a passive repeater?
I wouldnt think that it would have enough surface area to create this effect. Then again, i dont know how much you need. Anyway, ill be checking out the line of sight tomarrow so we will see thanks everyone!

i think he meant a water tower. they tend to be huge. any big object that reflects microwaves will work. one thing to keep in mind is the polarization may change after you bounce the signal, so experiment w/ that on the receiving end.

if all else fails, your bridge/repeater on a tower in between should work.

systemd0wn · 08-06-2002

haha. aight, that makes entirely more sence.

I had never thought of it for WLAN before, duno why! Aight, well im going to try and survey the area (dont live in this town, just started work here about 1.5-2 weeks ago

). I guess ill let you guys know what ends up happening, in case anyone else runs into the same sort of problem.

systemd0wn · 08-07-2002

what types of material are best for passive repeating? I assume the water tower wont absorb the signal, so could you give a small list of Good & Bad passive repeaters?

mshimek · 08-07-2002

We have a microwave system near us that has a passive repeater, that consists of 2 microwave dishes pointed 90 degrees apart on a tower connected by waveguide or Heliax. If I can, I will try a get a picture of it and post it. I have also seen microwave installations where the dish was mounted at ground level, to save line loss and costs, pointed to a reflector at the top of the tower. Maybe using two grid dishes might be a better way than yagis, because of the gain and surface area of the dishes. A water tower might be iffy, because of it's shape. A passive reflector should be flat. Two dishes would be most effective because of their narrow beamwidth, hence gain.

systemd0wn · 08-07-2002

Thanks! i would like to see some pictures if they are available to post. I dont think ill be able to use the water tower anyway, on my lunch break i realized that this location would hit the "front" or where the name is. and the other location would hit the "back" haha. so thats a no go. I kept looking for new towers and things that could be used as passive repeaters on my break, i think their are more Wi-Fi users here than i figured! Some stumbling is in order i think

If i cant find anything to use as a passive repeater (and its looking slim-none) hes going to contact the owner of that tower and see if we can get a spot for a decent price

The last couple days have been realy incredible, ive learned alot! thanks guys.

mshimek · 08-11-2002

Here is a commercial passive repeater antenna on a 6 Ghz system. All there is is waveguide between the two dishes. One site is only 1000 feet from the tower and the other site is about 10 miles to the west. This used to be a 2 Ghz analog system, but has been upgraded to a 4 T-1 digital on 6 Ghz. I used to maintain it when it was 2 Ghz.

ted · 08-12-2002

I plan to write to my ham friend. He has experience in passive repeater constructons, although for lower frequencies (70cm ham band). Basically, it should be possible to scale the design down to 2.4 GHz dimensions.

Also, after the experiment i participated in many years ago, he has used both purpose-built and "naturally occuring" objects as reflectors with certain success. I shall ask him for details, and report the results to this thread.

Ted

systemd0wn · 08-12-2002

thanks ted. i live in illinois so mountains arent that much of an option.. hahah. tree's ? corn maybe? haha. anyway. keep us up to date.

thanks

outcast_one · 08-12-2002

I have a 2 mile link setup using the old 900 wavelan cards/ wavepoint AP. A 2.4 ghz link was out of the question- too many trees, houses, powerlines etc. in the path. I bought a wavepoint II and 900 mhz pcmcia card for one end, and use an ISA wavelan card in an old pentium 133 running linux as a hardware bridge for the wireless card. Both ends use a 12dbd yagi from M2, and another benefit is you can use cheap high grade quad shield RG-6 for hooking it up (with a "F" to "N" male adapter at the antenna end). These old cards an AP's can be found on Ebay for little money. And they work. And they penetrate trees far better than 2.4 ghz equipment. Just an idea if you want to do some experimenting.....

systemd0wn · 08-13-2002

what kind of transfer rate do you get on this?

hollowing · 08-13-2002

...this might provide discussion.

http://www.rof.net/yp/alphaone/activ...tronics/sowap/

(Sorry if its been posted before, but on a quick look around it did not appear to have been...)

outcast_one · 08-13-2002

The link averages about .7 to1 mbit. Enough to play 320kbs mp3's and surf the net at 100+ kbs (cable modem) at the same time. Signal strength is about 35- 40% on the link. These cards advertise a 2mbs rate, and because they have much less overhead than 80211b (so i've read) they can get much closer to their theoretical transfer limit as compared to Wifi. It is a good working setup. No other (legal) setup would work for me in this link location.

08-06-2002	#18 (permalink)
systemd0wn Probematic Stumbler Join Date: Apr 2002 Location: Illinois Posts: 153	Ted, aight, so what your saying is use the other tower (if both buildings have line of sight to it) as a passive repeater? I wouldnt think that it would have enough surface area to create this effect. Then again, i dont know how much you need. Anyway, ill be checking out the line of sight tomarrow so we will see thanks everyone! __________________ Systemd0wn '311 Transistor, its a lightning resistor'

08-06-2002	#20 (permalink)
systemd0wn Probematic Stumbler Join Date: Apr 2002 Location: Illinois Posts: 153	haha. aight, that makes entirely more sence. I had never thought of it for WLAN before, duno why! Aight, well im going to try and survey the area (dont live in this town, just started work here about 1.5-2 weeks ago ). I guess ill let you guys know what ends up happening, in case anyone else runs into the same sort of problem. __________________ Systemd0wn '311 Transistor, its a lightning resistor'

08-07-2002	#21 (permalink)
systemd0wn Probematic Stumbler Join Date: Apr 2002 Location: Illinois Posts: 153	passive repeater what types of material are best for passive repeating? I assume the water tower wont absorb the signal, so could you give a small list of Good & Bad passive repeaters? __________________ Systemd0wn '311 Transistor, its a lightning resistor'

08-07-2002	#22 (permalink)
mshimek Chile-Head Stumbler Join Date: Apr 2002 Location: Wi-Fi Wonderland Posts: 57	Passive Repeaters DO WORK! We have a microwave system near us that has a passive repeater, that consists of 2 microwave dishes pointed 90 degrees apart on a tower connected by waveguide or Heliax. If I can, I will try a get a picture of it and post it. I have also seen microwave installations where the dish was mounted at ground level, to save line loss and costs, pointed to a reflector at the top of the tower. Maybe using two grid dishes might be a better way than yagis, because of the gain and surface area of the dishes. A water tower might be iffy, because of it's shape. A passive reflector should be flat. Two dishes would be most effective because of their narrow beamwidth, hence gain. Last edited by mshimek : 08-07-2002 at 08:27 AM.

08-07-2002	#23 (permalink)
systemd0wn Probematic Stumbler Join Date: Apr 2002 Location: Illinois Posts: 153	Thanks! i would like to see some pictures if they are available to post. I dont think ill be able to use the water tower anyway, on my lunch break i realized that this location would hit the "front" or where the name is. and the other location would hit the "back" haha. so thats a no go. I kept looking for new towers and things that could be used as passive repeaters on my break, i think their are more Wi-Fi users here than i figured! Some stumbling is in order i think If i cant find anything to use as a passive repeater (and its looking slim-none) hes going to contact the owner of that tower and see if we can get a spot for a decent price The last couple days have been realy incredible, ive learned alot! thanks guys. __________________ Systemd0wn '311 Transistor, its a lightning resistor'

08-06-2002	#17 (permalink)
sparafina Registered Member Join Date: May 2002 Location: TX,MD,NY Posts: 1,431	Yeah I watched his series on building a plane, so I'm not surprised if its a hoax.

08-12-2002	#25 (permalink)
ted Stumbling on Join Date: Aug 2002 Location: Houston,TX Posts: 47	I plan to write to my ham friend. He has experience in passive repeater constructons, although for lower frequencies (70cm ham band). Basically, it should be possible to scale the design down to 2.4 GHz dimensions. Also, after the experiment i participated in many years ago, he has used both purpose-built and "naturally occuring" objects as reflectors with certain success. I shall ask him for details, and report the results to this thread. Ted

08-12-2002	#26 (permalink)
systemd0wn Probematic Stumbler Join Date: Apr 2002 Location: Illinois Posts: 153	thanks ted. i live in illinois so mountains arent that much of an option.. hahah. tree's ? corn maybe? haha. anyway. keep us up to date. thanks __________________ Systemd0wn '311 Transistor, its a lightning resistor'

08-12-2002	#27 (permalink)
outcast_one cut/hack/modify Join Date: Apr 2002 Location: MA USA Posts: 30	900 mhz is the way to go I have a 2 mile link setup using the old 900 wavelan cards/ wavepoint AP. A 2.4 ghz link was out of the question- too many trees, houses, powerlines etc. in the path. I bought a wavepoint II and 900 mhz pcmcia card for one end, and use an ISA wavelan card in an old pentium 133 running linux as a hardware bridge for the wireless card. Both ends use a 12dbd yagi from M2, and another benefit is you can use cheap high grade quad shield RG-6 for hooking it up (with a "F" to "N" male adapter at the antenna end). These old cards an AP's can be found on Ebay for little money. And they work. And they penetrate trees far better than 2.4 ghz equipment. Just an idea if you want to do some experimenting.....

08-13-2002	#28 (permalink)
systemd0wn Probematic Stumbler Join Date: Apr 2002 Location: Illinois Posts: 153	what kind of transfer rate do you get on this? __________________ Systemd0wn '311 Transistor, its a lightning resistor'

08-13-2002	#29 (permalink)
hollowing the shadow is cast Join Date: Jul 2002 Location: SW UK Posts: 47	Its not passive but... ...this might provide discussion. http://www.rof.net/yp/alphaone/activ...tronics/sowap/ (Sorry if its been posted before, but on a quick look around it did not appear to have been...)

08-13-2002	#30 (permalink)
outcast_one cut/hack/modify Join Date: Apr 2002 Location: MA USA Posts: 30	Transfer rate 900mhz Wavelan stuff The link averages about .7 to1 mbit. Enough to play 320kbs mp3's and surf the net at 100+ kbs (cable modem) at the same time. Signal strength is about 35- 40% on the link. These cards advertise a 2mbs rate, and because they have much less overhead than 80211b (so i've read) they can get much closer to their theoretical transfer limit as compared to Wifi. It is a good working setup. No other (legal) setup would work for me in this link location.

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