Turnigy 9x8Cv2 sensitivity mods - RC Groups
Shop our Airplanes Products Drone Products Sales
Thread Tools
Jan 25, 2012, 01:28 PM
Registered User

Turnigy 9x8Cv2 sensitivity mods

I was surfing in another thread regarding RSSI levels and OSD stuff on the 9x8Cv2 receiver.

Was having a look at the performance of the receiver and it looked pretty poorly matched on the input, with a return loss of around -2.2dB.
( Meaning more than half of the power coming into the receiver from the antenna is reflected back out )

... I got bored and re-matched the receiver on the board. ( sad I know )

Looking from the antenna, the first part in series I changed to an 0402 0.47pF capacitor, the second part, a shunt to ground I changed to 0402 1.8nH inductor.

The receive looks a little better.
Return loss at 2.4GHz = -13.2dB, 2.5Ghz = -6.3dB

Sweeping RSSI levels with a pulsed signal generator on the input :

Input level (dBm), Original RSSI (mV), New RSSI (mV)
-100, 740, 700
-90, 616, 580
-80, 472, 420
-70, 340, 290
-60, 196, 130
-50, 68, 30
-40, 20, 20

Lower voltage levels on RSSI for a given signal input level are better.
Working it out, the mods above should give around 4dB better receive sensitivity.

Hope it helps! --

Quick info on the RSSI signal from the receiver below:
The screengrab below is a receiver receiving a transmitter that has been already bound.
The high part at around 2.07V is where the A7105 RX IC is being programmed with channel information (can see on data lines), the rough bit around ~750mV is where the receiver is waiting for the transmitter to show up (has no signal), the low part between the two vertical dashed lines is the rf level of the transmitter according to the table above. If I walk across the room and shield the TX antenna, I can see the part between the vertical lines go up, meaning less signal, which makes sense.

*disclaimer - I haven't tested these in the field yet - If someone get's a chance it'd be cool to see how it goes.
Also the parts are not that easy to solder without good irons.
Sign up now
to remove ads between posts
Jan 25, 2012, 01:57 PM
Registered User
Zen09's Avatar
Really nice (equipment there ) !
Now can we have some pictures to figure out what are you talking about ?

You're making flysky look dumb

Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion VRx sensitivity improvement Chyochyo FPV Talk 30 Aug 21, 2012 11:24 AM
Discussion 600E CF flight sensitivity Rotogod57 Large Electric Helis 1 Jan 13, 2012 12:16 PM
Discussion Anyone familiar with all the Turnigy 9x mods? carl1864 Beginner Training Area (Aircraft-Electric) 12 Jan 10, 2012 12:34 PM
Discussion Turnigy 9x v2 antenna mods brownviper1966 Radios 11 Nov 09, 2011 03:42 AM
Discussion Question on turnigy plush 30 mods rjwims DIY Electronics 7 Jul 17, 2010 03:50 AM