Pay attention to the SiK telemetry antennas

If you use chinese telemetry pay attention to the antennas they send you.
Many times they absolutely do not match the frequency of the SiK module.
I had 915 MHz telemetry with 2.4 GHz antennas, 433 MHz telemetry with 600 MHz antennas (???).
But even when they match, the performances are horrendous.
I created “Helical Round ‑ Wire Coils”, calibrating them with the NanoVNA V2.
The original antennas could not connect through 5 walls and a shutter, distance as the crow flies 50 meters.
With the antennas I have designed and built i’ve 88% telemetry signal.
I also open this post to discuss the various types and techniques of sizing based on the operating frequency.
Some useful links:


@marco3dr I changed topic to Radio Hardware

Agree, I most of chinese antennas are out of tune and sometimes work as a second harmonic with the obvious reduced gain and lower Q.

Working with the cheap Vector Network Analyser and using a quality 900Mhz antenna as a reference , I foud our that most of my pigtails where tuned around 1.03 Ghz :slight_smile:

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With that same analyzer, it becomes very easy to build your own simple dipoles that are tuned reasonably well. I get pretty good performance with a couple that I’ve made (not quite as fancy as those shown above).