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I am getting a lot of interference from wireless networks these days as everyone is being pushed into going wireless as the thing to do. Is anyone else getting any problems ?

Terry

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One of my park flyer fields is adjacent to homes. It is not longer possible to use my wireless video equipment there. I suspect it will may get worse for me, since I fly my small electric models mainly in local parks and schools which have homes nearby.

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One of the perks of living out in the sticks I guess... :) The only wireless networks around here are mine. I've got a 900MHz link to my ISP's base station thats rated at 25 miles line of sight, 5+ non LOS depending on whats blocking it, and a regular old 2.4GHz 802.11g network in my house that reaches out to my runway. I can shut them both down when I fly though, so it's not a problem.

Edited by KeithLuneau

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Now that you are talking about signals.

Do you think a capture video card on the pc with FM tuner and software can be used as an RX to receive the signal from the TX of the camera? I have an ATI all in Wonder with coaxial connector for antenna that looks alike the ones on the receiver that comes with some camera kits. Will this work?

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TV tuners are used to receive signals in.. the TV band. Not in 2.4GHz.

The first video transmitters I've used were like this, 224MHz. They've never proven to be usable in flight with poor range, and problems when the TX is moving relatively to the RX.

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I'm just going to bump start this thread with a request. I'm interested constructing a bandpass filter and test it's effectivness in reducing interference from wireless routers. Has anyone got construction details of suitable filters ?

Thanks, Terry

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Toko has some 3-pole filters that might work. But at microwave freq's, construction technique has to be fastidious. I suspect you could cascade some careful choices for tighter bandpass, then follow with a amp to restore lost gain.

For example, on ebay: Example of a Toko 13cm Filter. Hopefully Toko or a similar vendor offers something that will satisfy your app.

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Thanks for your reply, I am trying to find info for making filters if I can. I have the plan for a cavity filter which I think I will build but was hoping to find more.

Terry

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With my usual TXs/RXs I already won't see interference from WiFi if they're on a different channel unless the TX is very far away. Of course, if the channels overlap then three are white lines. But there a filter wouldn't help, as both frequencies are the same...

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With my usual TXs/RXs I already won't see interference from WiFi if they're on a different channel unless the TX is very far away

Yes this is what I believe is the case, I only seem to get it when my aircraft is over 500ft away or more.

Of course, if the channels overlap then three are white lines. But there a filter wouldn't help, as both frequencies are the same...

Can this happen ? I was not aware that WiFi use the SAME frequencies as we do, I thought they were just close.

Terry

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I was not aware that WiFi use the SAME frequencies as we do, I thought they were just close.

Here in the USA, we share the same 2.4Ghz freqs (its the popular ISM band). But the small space above 2450Mhz is not available to us amateur radio users (e.g., Ch-4 on Airwave), so we get less of the band to use legally.

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I just looked into it and it seems you are correct, 2.4-2.4835 at 100mW. I don't know where I got the idea that WiFi only used the lower bit of 2.4 but that what I thought until now :(

Looks like avoiding interference is going to be harder than I hoped.

Terry

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80211-frequency-channel-map.JPG

My AP will let me choose channels 1-13. I have trouble connecting with my other devices on CH13, so I set it on #12 so I know I can do tests on the lower video channels without messing up everything. When I test a TX on CH4 I instantly lose connection even with 10mW though, even not at close proximity.

What's good to know is that the channels are very wide, and some like #3 will even overlap 2 channels of the video system. They also overlap themselves, so in residential areas as soon as you have ~3 networks you're pretty sure that all your freqs will be occupied...

I'm basing myself on my system that uses 2414, 2432, 2450 or 2468MHz for the 4 channles, but anyway the other ones are usually close, 1-2 MHz off.

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Thanks for the Map Kilrah, that really shows how jammed packed the 2.4gig band is !

Add to that Bluetooth and video senders and now R/C radio with the Spectrum and it looks quite a mess...

Terry

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I found this report into the use of the 2.4Ghz band in the UK.

http://www.ofcom.org.uk/static/archive/ra/...2_4/ism_rep.doc

The bit that me laugh was when the report looked into how much interference would come from users of domestic wireless video and they said 'Although primarily intended for indoor use they may on occasion be deployed out of doors, e.g. for surveillance closed circuit TV links. Widespread outdoor deployment is considered unlikely due the relatively high susceptibility of analogue fixed frequency devices to interference from other sources in the band. In view of this and the relatively narrow bandwidths and low powers involved, analogue links of this type have not been included in the interference analysis.'

Terry

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