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Posted by erkq | Mar 06, 2015 @ 09:39 PM | 10,919 Views
I just knocked my LB ground unit off my desk. One of the antenna mounts broke out when it hit the floor. What a dope! I opened up the LB and took the broken mount out. See pic. It's an SMA -> MMCX that's about 5cm long. So I found a replacement that's 10cm long, no big deal. But it's an RG-178 cable and "they" say it's good to 11GHz. So, is this the right impedance? I'm almost sure it will work, but if it doesn't it's a disaster. If it loads the Tx wrong the Tx will blow at some unpredictable time. See second pic for fixed LB. I used tape to keep the strain off the MMCX connection. The LB has no range check, so I'm spooked!

I used this cable. It's an RG-178 good to 11GHz:

EDIT: The grounds are really close to each other on the left connection. Does it matter if they touch? I'm certain it's a common ground, so it shouldn't matter. But at these frequencies, I can't be certain.
Posted by erkq | Dec 04, 2014 @ 01:04 PM | 7,329 Views
I broke the tiny micro HDMI male to male cable that came with the Walkera G-3S gimbal and couldn't source a replacement. Email to Walkera has gone unanswered so far. So I took that as an excuse to get a DJI Lightbridge, because you can actually buy their replacement HDMI cable!

It's pretty great so far. I have it working with my Taranis and Galaxy Note 4. It mounted well in the frame. Still have to do a "signal diagnostic" check. I will do that with and without the 5.8GHz pilot cam active. The 5.8GHz antenna is kinda close to one of the LB's antennas.
Posted by erkq | Dec 03, 2014 @ 12:29 PM | 7,846 Views
The Walkera QR X800 barely limps into the air with a Sony RX100 and Walkera G-3S gimbal. So I upgraded the motors and props to GREAT effect. Here are the parts I used:

(4) Foxtech 5010 288kv motors:

(4) Tarot 16mm Suspended Motor Seats:

(4) RCMC 30HV SimonK ESCs:

(4) NEEWERŪ Carbon Fiber Tube 3K 16mm Diameter 330mm Long:

(2) Sets of 1855 MKII Carbon Fiber Propeller CW&CCW (4 total)
But NOW I went all spendy and got great efficiency (see their chart, shown to be pretty accurate by a guy testing on YT):
(2) Sets of Foxtech Supreme C/F Propeller(18x6.1)

(4) 3/4" Hose clamps... really... they work great!

I couldn't find motor mounts that would fit Walkera's non-standard 18mm arms. Fortunately those arms have an inner diameter of 16mm, perfect for slipping a 16mm CF arm into. Leave enough out to attach the motor mounts. Use the pipe clamps to secure the 16mm inside the 18mm tubes. The end of the 18mm tubes have a great shape to allow the pipe clamps to really compress the outer 18mm against the inner 16mm.

Two of my 16mm tubes wouldn't slide all the way in their 18mm hosts, so I knocked it in as far as I felt safe with a hammer and then used a...Continue Reading
Posted by erkq | Nov 07, 2014 @ 07:08 PM | 15,188 Views
Update: I installed a Gentles Gent-wire camera controller. Problem solved! Read the later posts about it.

Here are the particulars on the RX100 camera trigger. The trigger board is almost a complete solution. But it releases the Focus line when it trips the Shutter. The RX100 requires both Focus and Shutter be held to take a pic. So I used a PicoSwitch to do that to hold the Focus and Shutter lines together in the Shutter position. Here is a link to the PicoSwitch:

It's a kludge, but it works! The diode idea did not work, so the PicoSwitch (or some rc relay) is necessary. Below are the pics with explanations in the captions if needed. I bought this to reverse engineer the wiring:

I have no probes small enough to do continuity testing on a micro-USB plug, so I cut the cable, noted how the switch works on button side, tested what I learned on the camera/USB side and used the camera/USB side in my cable.
Then I used this Camera Control/Trigger board:

If you use this particular trigger for your cable, it's Common = Red, Focus = White, Shutter = Yellow.
You have to use 2 channels on the radio and program a 3-pos switch to trip the PicoSwitch when the control switched is moved to Shutter. The 3 positions are: Standby, Focus, Shutter. Works perfect!

It may be possible to put both the CC board and PicoSwitch on the same channel with a "Y" but I have so many channels available on my Taranis I didn't bother.