Could very close placement affect each other to the point of causing interference or weakening the signal?

flight rx antennae are quite close to the 600mw 5.8 video tx.  Most importantly could the 2.4 signal be jeopardised?


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Hi. Looks like your receiver antenna is nearly touching the 5.8 video antenna. That wire antenna from the receiver is at some point in its length resonate with 5.8 ghz and RF energy will be introduced into the receiver electronics, possibly swamping incoming 2.4 ghz signals. Simply stated you should always place antennas for different electronic devices as far apart as is possible. 5.8 ghz wave length is about 2 inches long. Radio frequency energy is subject to the inverse square law just like light. So if your receiver antenna is 2 inches from the 5.8 antenna it is receiving twice the amount of interfering energy that it would receive at 2.8 inches, to half that again move them apart by 4 inches and cut it in half again by separating them to 5.6 inches and so on. separate them by as many wave lengths as possible. Small cheap electronics rarely have good filtration against interference. Once you've separated the antennas by as far as possible, if interference is still a problem, install a copper wire mesh screen, perhaps 3 inches in diameter above the 5.8 ghz antenna in your installation in the photo. It could be fitted to the 5.8 coax by poking a hole in the screen and gluing it in place an inch or more above the antenna. This would create RF shielding, keeping the the 5.8 GHZ RF from radiating toward the other electronics. Grounding the mesh would further enhance the shielding.

Hope this helps


Hi Geoffrey

Thank you so much for a very detailed reply, love to learn the theory about how this equipment works and not just use it.   I heed all your advice and have since moved the components as per the pics, just haven't tried the copper shield yet.   Did another test flight today and although signal is better, it's still nowhere as good as a previous setup I had running a 200mw vidtx, I was getting up to 1km quite easily with that one but now only 100m with this current one (600mw 5.8) tx.    I think I've figured it out though, mismatching vtx/vrx and though they're the same brand, I can only put it down to that.  The vrx is quite old, I can get a signal on all channels and one doesn't seem to be stronger than the other.  The spironet antennae are installed correctly according to tx/rx. 

As you can see in the pics, components are well separated now, I even shielded the Naza vsen unit with silver foil.  These problems can be really frustrating especially before a up and coming short-film shoot but trial and error will eventually solve most issues I believe.  




I think you may be on to something when you said that you're receiving a signal on all channels but one is not stronger than the other. I  think you should receive a strong signal on only one channel and maybe just a little hash on adjacent channels. Even though they are the same brand name something is amiss. Check out the transmitter frequencies and compare them to the available receiver frequencies in the product manuals for both. I suspect that your transmitter is transmitting on a  frequency close to but not exactly on an available receiver channel. The fact that you can receive a signal on more than one channel says something about the quality of the units...or that you may have a problem where the coax cable connectors are not completely threaded tight.

  I've noticed that manufactures don't use standardized channel assignments, especially if the equipment is manufactured and intended for use in countries other than the US. Iftron, which is American made, uses different channel assignments than those manufactured in Asia. Maybe time to upgrade the receiver with one that exactly matches the transmitter.


Thanks Geoffrey.  I will check out the frequencies side by side and let you know what I find,  I don't have the manuals anymore, bad habit of throwing them away but easy enough to find on net.  I will most likely order a new set (rx/tx) so that I again have a matching pair from the start. 

again, thanks for the advice..  that's what I love about diydrones, people can be so helpful and likewise, I try to lend a helping hand. 

Hi Geoffrey, finally got back to this.  The frequencies match up and I've solved the problem.

Turned out that it wasn't the rx or tx but the spironet antennae.  I switched to cloverleaf/skew planar and now I am getting very good range, so far 1km easily which is what I needed.  Question now is, why are the spironets so poor? 

I wish I had done this from the start, would have saved a lot of time but that's the nature of this hobby I guess, lots of trial and error sometimes. 

Thanks again for suggestions

 Could be anything causing the problem. My guess is poor antenna connections. Most are made with crimp connectors which is a joke at these frequencies. Glad the problem is solved. 

 Do you still have a signal on adjacent channels or did that go away when you changed antennas? 


actually haven't checked adjacent channels, I was so happy to finally get good range that I've neglected to check for stronger signals on other channels..  well I can't do that now, had a bad crash the other day therefore not getting any range at all, haha.

Luckily everything survived, will rebuild rather later than sooner, need a good break from a solid two years of multirotor madness.  

I have another quadcopter and a tri to play with in the meantime, will have a bit of fun instead of building all the time.


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