The exactly 915mhz dipole antenna.
To increase telemetry range I made a half wave dipole antenna as per IBcrazy’s guides for the 915mhz. Many stock antenna from non 3DR sources have no markings or even 2.4ghz written on them.
The Dipole was great, but required caliper measurements and gluing/mocking up antenna tube casing supports, ensuring 180degrees, didn't look sexy so on.
This is why the “exactly 915mhz dipole antenna” was created. It’s a very light weight antenna (Jackless) design which also is a template for the precise length of the antenna trimming, and ensure it’s a straight 90degree bend to form 180degrees.
I made mine through shapeways. Comes in black or white, I’ve now selected it as "available for sale to the public".
Instructions after image Let us know your thoughts!
Instructions:
- Remove PCB antenna jack
- Solder on 2 wires as per image. Around 10cm (will be trimmed later)
- Clip on bottom half of antenna shell and fit wires into the grooves
- Push in top half and antenna shell and secure with method of your choice (tight fit design, it stays in place without extra tie, but I used heat shrink. CAREFUL if using heat shrink, the material warps if heat gun temp is too high or used for too long)
- Trim wires. VOILA it’s now for 915mhz exactly!
Replies
Hi from France
About the basic (cheaper) 3 D Robotics telemetry in 915 mHz.
associate to an APM 2.8 update with APM copter and Mssion Planner as gui.
I maid this rainy sunday two "rustic" antennas, stick, dipole, half wave, SMA male plug ; In order to replace the "originals antennas" which seemed to be tuned to all waves except the 915 mHz one.
Basic testing (one meter test) ==> with originals antennas shows the very bad achievement of the 25 Netid ( RSSI/remRSSI 121/41), the same for "Noise" (73/18).
Better achievement around 75 to 200 NetiD (121/135) and 33/17 for noise.
Using my news antennas ==> achievement was 216/217 and 30/17 for noise.
Success then, for a very cheap and overall reliable antennas
best regards
thanks mate. Yea i use it for my tx and on the drone. Haven't used it on the laptop. Maybe i'll create one that's 90deg in the future.
Theory aside,
I originally had signal drops 500m away with the antennas that came with the radio kit. But now i'm getting 50% signal at 500m.
That is a nice improvement on the signal strength....certainly worth exploring.
Most laptops will cause the antenna to be mounted in the horizontal plane. I prefer a vertical antenna myself in order to match the vertical antenna on my quadcopter. You will lose some signal if you are cross polarized....which is more than I want to toss away.
Novel idea though.