I am having problem with upload command from flight data. Eg Change altitude, restart mission ect. I do not have this type of problem with the previous Mission Planner. When I try to change altitude, a fail massage window appear. I also can not write param to APM while flying. But if the plane had landed and close by my computer, there is no problem. Anyway I can establish connection between the two data modem with ease.

I'm using RDF900,  am I doing something wrong in 3dr radio setting ? Thanks for your help.

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Yea I just heard about event38 another thread was talking about this. I made my own.


I didn't know about them. It looks like they don't carry all the neat stuff that Seppo does. Btw, Seppo sells in $AUD and right now for us in the USA, it's a bargain if you don't mind the wait time. Those flex antennas are great. So light and they  are dipole to boot.

I will definitely be ordering a few of those antennas.

I asked the event38 guys and they said they get all their supply comes from rfdesign. 

thank you again for all of your invaluable help & input!

So is the general idea they glue onto the vertical stab? What works well on a conventional fixed wing plane? With the RFD I'd want two antenna's ...so should one be mounted vertically on the vertical stab and then one on the fuselage side so it's vertical too? It's a semi large plane. A old school Sig Seniorita / 4stroke.

Well, yes. :-) You see, I find not need for a RFD900 on the airborne side. I still get 4-5 miles. Now, if you want to go further than use the RFD900. That said, I only need 1 antenna. :-)

You can put it anywhere you want but keep in mind it is a 1W Tx at full power. Optimum would be at angles and 1/4, 1/2, etc wave length apart. That usually isn't possible. The antenna comes with a self stick adhesive. You can put it on the vert. stab like I did on one plane or on a tongue depressor and hang it in the breeze. You have to read up on antenna theory and plan accordingly. Remember your GPS is a Rx. If you use VTx, you now have 2 Tx's and some misc Tx like camera and ESC. You have Rx Control, Rx Telem and Rx GPS. It takes some thinking and planning.

Your welcome.

You should ask them to carry his complete line up...

There is an RCGroups RFD900 thread, have you searched it?

Seppo used to hang there but has been absent for some time. Still there is a lot of good info there. And many who can help.

IBCrazy has some good basic antenna stuff too. In general, you want all Rx to be lower freq than the Tx. That way you avoid harmonics crapping on your Rx's. Distance is your friend. Stay away from carbon fiber and metal reflective surfaces.

I do notice some major servo jitter with the RFD900 on high. I'd like to get it as far away from my other stuff as possible. I saw one guy took a shielded USB cable and made his own telem radio extension cable I think I might give that a go. The set up is a APM 2.5 with a media tech gps. Funny how that's already outdated! ha But it has worked perfect never had a problem with it. I'd like that trend to continue! Have not tried the RFD900 in the plane yet. Weather.... kids.... etc. But I'm glad I saw your info here about the thin antenna's! That seems like the best bet for my plane. Should stick on the monokote great.

Oh yea this guy!!!! I bookmarked this thread awhile back. How cool was that for him to spend all that time posted all that for us. Nice.


again... wrong forum.. opps sorry

I did mention it - hopefully they will. 

so i swapped out my ground station modem with another, and now I am getting significantly higher rssi:

what RSSI values should I expect at close range? radios are about 5 meters from each other on the above graph. Not sure if the noise values are high.. the local radio is a bit close to my computer/monitor etc.

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