Espritmodel.com Telemetry Radio
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Old Nov 21, 2011, 03:19 AM
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Originally Posted by lrrps View Post
What kind of gyro do you use, personally I have the Range Video OSD that also serves as an autopilot, I always activate the Fly by Wire function that helps keeping the wings level.


I'm hoarding these ESKY 704 rate gyros. Nothing fancy but you can't find them in stores or online anymore. The only place you'd have luck is in the for sale section in the heli section for people parting out their esky helis.
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Old Nov 21, 2011, 03:36 AM
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Originally Posted by chatch15117 View Post


I'm hoarding these ESKY 704 rate gyros. Nothing fancy but you can't find them in stores or online anymore. The only place you'd have luck is in the for sale section in the heli section for people parting out their esky helis.
That's a brilliant idea.
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Old Nov 21, 2011, 04:04 AM
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yeah I got a good deal on them. My first was $20 but I got the other 3 for $10 each shipped
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Old Nov 21, 2011, 06:52 AM
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Originally Posted by lrrps View Post
I got a question that has nothing to do with a CP antenna, pls. forgive me if this is out of place.

People at my club told me that in order to get maximum GPS signal, the antenna has to be installed on an aluminum foil, is that confirmed?
That is complete garbage. Aluminum foil will do nothing but harm your signal.

-Alex
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Old Nov 21, 2011, 07:35 AM
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ok wow... I went out this morning and it was complete garbage. I think it's because I was parked next to a 7 story building. I think the RF was reflecting off the building and was causing really bad multipathing.

So note that any structures near you really do make a difference!!! I'll look for a new place to fly that's far away from any buildings.

Skip to 3 minutes and you can see that my range is exactly the distance of my receiver to the building.

????????/// (6 min 26 sec)




I chose that spot because the sun was in my eyes. Normally I go out in the evening but I wanted to try out my new firmware on the OSD ASAP
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Old Nov 21, 2011, 07:57 AM
Ed @ Experimental Airlines
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CP interference from double-reflection?

I have a really esoteric question about circular polarization.

I made a right-hand SP receiver and CL transmitter antenna pair for 5.8gHz, mounted inside a foamboard fuselage tube and flying within 300m. They work phenomenally in the confined and RF-busy urban area where I fly.

There is still one zone on my field where I consistently get interference that seems to be at the focal point between a large 12' freeway noise abatement wall and the side of a Costco (also huge, of course) oriented at 90 degrees to one another.

Is it plausible that some of the transmitted reflection off each large surface is being reverse-polarized and then re-polarized by the other, causing a big multipathed correct-polarized signal back to the receiver?

I'm familiar with this bounce-bounce principle with certain optical systems, like prismatic reflectors, but am curious if it applies to circular polarization.

Otherwise the antennas work fantastically! Thanks Alex!

Ed
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Old Nov 21, 2011, 08:43 AM
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Originally Posted by IBCrazy View Post
That is complete garbage. Aluminum foil will do nothing but harm your signal.

-Alex
Thanks Alex, I won't do the garbage mod then.
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Old Nov 21, 2011, 09:54 AM
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Originally Posted by IBCrazy View Post
That is complete garbage. Aluminum foil will do nothing but harm your signal.

-Alex
this was suggested in the remzibi osd thread:
http://www.rcgroups.com/forums/showp...postcount=3500

i think the theory was to use aluminium foil to shield the gps receiver from the rest of the electronics, particularly in a confined area such as a multicopter.

i have not tried it out so i don't know if it actually works.
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Old Nov 21, 2011, 10:47 AM
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Originally Posted by chatch15117 View Post
ok wow... I went out this morning and it was complete garbage. I think it's because I was parked next to a 7 story building. I think the RF was reflecting off the building and was causing really bad multipathing.

So note that any structures near you really do make a difference!!! I'll look for a new place to fly that's far away from any buildings.

Skip to 3 minutes and you can see that my range is exactly the distance of my receiver to the building.

http://www.youtube.com/watch?v=taXy6cBpHtk



I chose that spot because the sun was in my eyes. Normally I go out in the evening but I wanted to try out my new firmware on the OSD ASAP
That is noise floor without a doubt. Something is on your channel. See the fuzz? That's external interference. Circular polarization is not going to fix that. You need a different location or frequency.

-Alex
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Old Nov 21, 2011, 10:49 AM
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Quote:
Originally Posted by ExperimentalAir View Post
I have a really esoteric question about circular polarization.

I made a right-hand SP receiver and CL transmitter antenna pair for 5.8gHz, mounted inside a foamboard fuselage tube and flying within 300m. They work phenomenally in the confined and RF-busy urban area where I fly.

There is still one zone on my field where I consistently get interference that seems to be at the focal point between a large 12' freeway noise abatement wall and the side of a Costco (also huge, of course) oriented at 90 degrees to one another.

Is it plausible that some of the transmitted reflection off each large surface is being reverse-polarized and then re-polarized by the other, causing a big multipathed correct-polarized signal back to the receiver?

I'm familiar with this bounce-bounce principle with certain optical systems, like prismatic reflectors, but am curious if it applies to circular polarization.

Otherwise the antennas work fantastically! Thanks Alex!

Ed
Possibly. Reflections off of concrete reinforced buildings and metal structures usually retain a fair amount of signal strength so it's certainly possible.

-Alex
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Old Nov 21, 2011, 10:53 AM
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Originally Posted by noobee View Post
this was suggested in the remzibi osd thread:
http://www.rcgroups.com/forums/showp...postcount=3500

i think the theory was to use aluminium foil to shield the gps receiver from the rest of the electronics, particularly in a confined area such as a multicopter.

i have not tried it out so i don't know if it actually works.
In the case of the quad copter the effects of the aluminum plate outweigh it's benefits as far as the antenna is concerned. The metal plate will throw off the resonance of the GPS antenna. However the electronics may benefit from less induced noise.

-Alex
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Old Nov 21, 2011, 04:29 PM
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Lima-Peru
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Hi IBCrazy, just bought your Blubeam whip set antenna from your website, could you please send me some recommendations to install it in the bixler?, I will use it with the HK 5.8 Ghz 200mw, I didn't have it yet but I what to be prepared.
thanks
werner
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Old Nov 21, 2011, 05:00 PM
Flying low is expensive.
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I'm not Alex, but there are a few options for this. You could place your VTx on the wing saddle and run the antenna out to the wing, you could place it on your tail, and run it out onto the boom. There are others, I'm sure, but that's what I came up with off the top of my head
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Old Nov 21, 2011, 05:08 PM
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I recently built the cloverleaf and SKW antennas for a 200mw 5.8ghz tx/rx. I haven't had much success with them so I was wondering about left hand polarization vs right hand. My understanding is that it does not matter which I use as long as both are the same. I mean, the polarization is not related to a particular tx or rx, right?
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Old Nov 21, 2011, 05:35 PM
Flying low is expensive.
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Originally Posted by daronj View Post
I recently built the cloverleaf and SKW antennas for a 200mw 5.8ghz tx/rx. I haven't had much success with them so I was wondering about left hand polarization vs right hand. My understanding is that it does not matter which I use as long as both are the same. I mean, the polarization is not related to a particular tx or rx, right?
You summed it up pretty well. As long as you have two rights or two lefts, it'll work. What exactly are your issues?
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