Make Turnigy module removable with existing hard ware

[ShowMaster]

Since upgrading to Frsky I'm thinking of just putting the FlySky stuff in my microwave....set to popcorn.


ShowMaster
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[kaos]

you can send it to me. I think I still have a few planes to be built that only flies with direct visual.

[ShowMaster]

you can send it to me. I think I still have a few planes to be built that only flies with direct visual.

actually they've gone to a forum member already but just thought I'd jump on the microwave bandwagon topic.
I used to tune 72mhz rx by putting the tx in cavities like the dryer or fridge but never used the microwave oven. I needed the weakest signal to align the IF stages on the AM RXs. The trouble with all the cavity ideas is it doesn't check what the link will do when the rx is mounted in the plane and your holding the tx free of all metal that can reflect or direct the signal in different directions. That's where a reduced tx power condition in the actual tx being held at the location for flying is the best test. I really like the Frsky system for those and the telemetry reasons. I know real time what's going on. So I'm totally Frsky now and haven't looked back in over a year.




ShowMaster
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[jhsa]

You are correct showmaster, but when the modules don't have the range test option and the alternative is walking or driving, the Microwave oven could be an option, specially if there are obstacles around the area you fly, and that could prevent a good full range test..

[kaos]

Maybe put the reciever in the microwave and move the tx.
Or at least unplug the microwave.

what does unplugging the microwave do?

[jhsa]

Your wife can't turn it on with your tx inside and fry your fun

[kaos]

you mean it won't act like an antenna and amplify the signal.

[jhsa]

exactly.. after all microwave ovens work more or less on the same frequency I think.. wife is not always on the same frequency though, hence my post above

[rperkins]

When i had a wife the freq would change just when i got used to the old one.

But yea was thinking of the antenna effect, which might not even apply at 2.4ghz.
My mcpx is so small i cant see heads or tails long before i run out of range.

[pmullen503]

Your wife can't turn it on with your tx inside and fry your fun

Fry-sky mod?

[kaos]

I think the wives will have heart attack when those sparks coming out of the oven if they try to do that.
Hmm, they will learn 'don't mess with my toys' really fast.

[jhsa]

No, they will make us buy another one because we did put our toys inside it and destroyed it.. even if THEY turned it on..

João

[kaos]

shame on you. doing all those mod and burned your board, then set up your wify to blame on.

[jhsa]

just unplug the oven and you'll be fine.. nothing will burn and no one to blame ..

[MostlyHarmless]

Based on this thread I modified my module similar.

I used 6 layers of approximately 1mm thick plastic (that used to be a DVD case). The hole is 3/8'' making for a nice tight fit. Two layers cut like washers go on the outside

and four on the inside.

That lets the antenna sit just in the right spot so that it doesn't put pressure on components inside.

I was originally thinking about using something different. This is an "old" D-Link 2.4 GHz WiFi router. It doesn't do 802.11n, so I have no use for the router itself. But those parts look useful for sure.

That's a "through hole" angled SMA connector and a 2 dbi 2.4 GHz antenna. I'm saving this for another project.


Regards,
Jan

[Ozzy]

I found this web site, shows how to make a 6dBi wifi antenna, pretty simple.

http://martybugs.net/wireless/collinear.cgi

I made two in 5 minutes, connected them up to a 5GHz spectrum analyzer and ran some relative comparison tests.

I tried four different antennas;
a D-Link 2.4GHz wireless router 2 bDi antenna first to get a baseline (it's very similar to the stock 8ch Rx antenna),
stock Turnigy 8ch Rx (dipole),
and the homemade 6 dBi (18 AWG and 20 AWG).

I placed my Turnigy er9x at 12 feet away (I think that was a mistake now),

I was getting a reading of -23.1 bDi with D-Link antenna,
exactly the same -23.1 dBi with the Rx 8ch antenna,
then swapped to the homemade 6 dBi 18 AWG antenna, it tested at -17.4 dBi, very impressive,
then I switched to 20 AWG solid wire (more plane friendly), it tested at 19.3 dBi.

I really think I need to do a farther distance and test in a cleaner environment (my work lab has a lot of equipment, but Tx and Rx antenna distance never moved).

Anyways, I started another thread comparing ~7 Rx's for range distance and wanted to get a better range for my two new planes, maybe this 6 dBi antenna on the Tx will do that, more testing needed.

6 dBi antenna Ebay version
http://www.ebay.com/itm/6-dBi-2-4-2-5GH ... 43b3c3c52b

I was thinking of mounting the 6 dBi antenna on the back of the stock RF module, since its longer it will stick up about 2 inches taller than the stock antenna in the stock position.

I understand that a larger gain antenna can reduce the gain on axis of the antenna.

Any thoughts or comments?

Oz

[ShowMaster]

Usually using antenna gain only to increase range comes with limitations. The concept is that if you start out with let's say 50 Mw of omnidirectional power (donut shape, dead at the tip), its spreading that power in a 360 deg pattern. If you alter the antenna length, and with a matching network still maintain 50 ohms you can direct the energy to me more directional. This give an apparent signal gain weather transmitting or receiving. What you sacrifice is the 360 deg radiation. This translates in having a system that's more directional and have less gain when off access. Much like a flashlight berm if you move it from its target.
No "free" rides modifying just the antenna gain.
Adding much more power to an existing system that radiates 360 degrees will not only give more range but will retain its omnidirectional bennifets.
Again, not a free ride as more power can cause local trouble in the RX or TX circuitry due to its proximity.
Best advice is to trad up on the success and failures on the dedicated fpv forums. They've been there and know what works.
Rf is magic and gravity never rests.


ShowMaster
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[minbari]

Usually using antenna gain only to increase range comes with limitations. The concept is that if you start out with let's say 50 Mw of omnidirectional power (donut shape, dead at the tip), its spreading that power in a 360 deg pattern. If you alter the antenna length, and with a matching network still maintain 50 ohms you can direct the energy to me more directional. This give an apparent signal gain weather transmitting or receiving. What you sacrifice is the 360 deg radiation. This translates in having a system that's more directional and have less gain when off access. Much like a flashlight berm if you move it from its target.
No "free" rides modifying just the antenna gain.
Adding much more power to an existing system that radiates 360 degrees will not only give more range but will retain its omnidirectional bennifets.
Again, not a free ride as more power can cause local trouble in the RX or TX circuitry due to its proximity.
Best advice is to trad up on the success and failures on the dedicated fpv forums. They've been there and know what works.
Rf is magic and gravity never rests.


ShowMaster
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Exactly right. What you are taking about is called "beam width" higher the gain, narrower the beam width.

To give you some examples. We have some 9dbi omni ant at work. Beam width is 23°.
The 15dbi omnis we have are 8° (+ 4° above center Line, -4° below center line). At 10 meters up on a mast, you have to be 3300 ft away to be in the main lobe on the ground. That does not take fresnel zone into account either.

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