My indoor intereference

[mrfliboy 0]

Heres a clip of my el cheapo indoor interference. Just to confirm I believe this is all multipath interference. I do have the tx located approx. 3" from the Rx and esc. I'm planning on next to move out to the wing maybe 10 to 12" away, but am not sure If this would help?

Also heres the RCGroups thread about the build.

http://www.rcgroups.com/forums/showthread.php?t=1112425

I'll be flying in a Dome this Fri and Sat to see if any things change. All in all for the $$ I'm happy but don't mid tinkering to attempt improvement. Thanks to any and all for ideas and help.

[KeithLuneau 0]

Definitely looks like multipath to me. It's not uncommon to see it indoors where the signal is free to bounce off of may reflective structures in the building.

[mrfliboy 0]

Thanks Keith,

I'm just curious to if I change anything would it be worthwhile, all in all its usable as is.

[Kilrah 2]

Apart from adding a diversity receiver setup, not much you can do. If you have a patch RX antenna at hand you can try it, it can help reducing the bounced signals coming from the back side a little.

[mrfliboy 0]

Thanks Kilrah,

I've thought about the GP Patch ant. but the fact that I'm adjusting the Freq. by a knob means I'm not sure exactly the frequency to size the Patch too. And the fact It'll be quite 900mhz large. LOL

I was really hoping to hack the Tx apart from the cheapo Cmos camera and use my CCD camera but was unable to figure that one out.

There is a very lightweight 900mhz tx available but pricey that I've thought about.

http://cgi.ebay.com/Videocomm-T-906-Wireless-Video-Transmitter-900Mhz_W0QQitemZ300097937485QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item45df3b204d

Which is ridiculously priced but lightweight. LOL

[Mr.RC-Cam 129]

If you don't want to build the GP Patch then add a DiY Windsurfer reflector to the Rx antenna (scaled for around 1GHz). The goal is to alter the omni Rx antenna so it is directional; As Kilrah already mentioned, this will usually reduce multipathing a bit.

By the way, your multipathing seems to be much more exaggerated than usual, even in your horrible indoor environment. I have a feeling there is something else going on. I'd suggest you fly your model outdoors, in a wide open field away from EVERYTHING, and post a video of it.

[mrfliboy 0]

Thats too funny RCCam, I have not tried outdoors yet with this setup. Zero wind today hazy sky, I'll be back in a few hours. Thanks

The windsurfer idea sounds cool. More searching and reading. Thanks again.

[Kilrah 2]

By the way, your multipathing seems to be much more exaggerated than usual, even in your horrible indoor environment.

He says it's one of these systems with the frequency tuning knob. I wouldn't look too far for the cause.

[Mr.RC-Cam 129]

Zero wind today hazy sky, I'll be back in a few hours.

I made some calls to my wind people and had them dial in a calm day for you. Enjoy!

He says it's one of these systems with the frequency tuning knob. I wouldn't look too far for the cause.

.... don't have to look far at all.

[KeithLuneau 0]

How much will it cost me for indefinite calm days?

[mrfliboy 0]

I gather a few missed out on the great tuning knob. LOL

After launch is where i "retune" hence the black screen. All in all not bad for outdoor. Whats the verdict on this one??

Btw thanks for the calm winds, flew for over a hour until the rain drops started. I'm really starting to enjoy my modified Fox.

Thanks for all the help. We need a lightweight 900mhz Tx.

Edited November 5, 2009 by mrfliboy

[Mr.RC-Cam 129]

Whats the verdict on this one??

Performance wise, I'd give it very low marks. But if you enjoy using it then that is all that matters.

Overall, I don't have any simple minded recommendations for making it a better system.

[Terry 5]

WOW..That reminds me of my very first attempts about 10 years ago. Good fun but plenty of room for improvement.

Terry

[KeithLuneau 0]

For what it's worth, I messed around with a similar transmitter/receiver like this for fun, and found that using a stable voltage on the transmitter and receiver helped with frequency drift. I ended up using a Any Volt Micro on the transmitter, and a 12V NiCd pack on the receiver. I also made a Goof Proof patch scaled to it's frequency, and that was a huge improvement. It was all good fun, but barely worked at best... It was still good fun bombing around the back yard though, not really worried about crashing the plane or the video gear. I still have that stuff, maybe I should dig it out and throw it on a Pico Stick or something! lol

[mrfliboy 0]

Thanks again to all that have replied, a few things I noticed on these flights. Worst signal occurred when generally overhead of antennae. Distance and height affected signal (doh). The overall picture was much better than the indoor flights.

The tx and camera are powered from a 7a Pixie esc with a 2 cell 150ma. The Tx is powered directly off the 2 cell and the camera from the 5v side of esc. My whole ground station is powered from a 3cell 2200ma. At the end of the flights ground station was 11.6v and 2 cell lipo was 7.4v.

GP ant will be next I guess. Overall I do not believe there is any RF interference, just poor quality of system. I'll be in a dome this Fri and Sat with it and see if anything changes. I'm not looking for long distance but reliable signal for indoor use.

I presume the 1.2mhz setups would yield similar results? Still have yours RCCam? Thanks again

[Kilrah 2]

The Tx is powered directly off the 2 cell and the camera from the 5v side of esc.

Is that normal? Usually those transmitters expect 5V as well...

[mrfliboy 0]

This one had the regulator built into the cable for the camera and supply power was a 9v battery. I did test the tx down to 6v with my adjustable DC power supply and all seemed well. (at least in my hobby room)

[mrfliboy 0]

Made it to the Dome last nite. Much better (for this system) compared to the Field house indoor vids. I found by pointing the Rx ant straight out was best reception. I'm thinking maybe a shield of sorts for the ant?

Anyway I cannot see much improvenment from here, but is usable for me to practice a little with.

[mrfliboy 0]

Found the template for 2.4, now how would I scale for 910mhz??

http://www.freeantennas.com/projects/template2/index.html

As always thanks in advance

[W3FJW-Ron 0]

Multiply dimensions by 2.66 & you'll get there.

[mrfliboy 0]

Thanks so much!!

[mrfliboy 0]

Very happy with the overall improvement. In the dome last nite was able to fly very well with no drop outs and just one glitchy spot. Quite impressed with the overall boost the windsurfer gave.

Thanks again