(ΦωΦ) Catudp's blog
Looking Back (with Polar Plot – Jan 22, 2026)
Before talking about the V4, let’s review the previous configuration. (See the polar plot image from 01-22-2026.)
Measured Results (Early Configuration)
There was a brief issue caused by a damaged SMA cable (possibly due to UV exposure — the bundled cable degraded quickly).
After replacing the cable, performance slightly improved.
Statistics:
- Aircraft seen: 674
- Max range: 85 nm
- Gain: 38 dB
- Antenna height: FL + 70 inches (1788 mm)
My ranking reached 39,324 globally.
Performance was stable. I could have stopped there.
At this point, I started thinking about a hardware upgrade.
Current Dongle (Clone RTL2832 SDR)
- Aluminum enclosure
- 25 MHz – 1760 MHz coverage
- VHF/UHF support
- AM / NFM / FM / DSB / USB / LSB / CW
- ±0.5 PPM TCXO
To decide objectively, I compared both models.
| Feature | Nooelec v5 | RTL-SDR Blog V4 |
|---|---|---|
| ADS-B (1090 MHz) | Excellent | Good |
| VHF Airband | Excellent | Good |
| HF (Shortwave) | △ Requires upconverter | ◎ Direct samplding |
| Noise resistance | Excellent: Low noise | Good: sensitive |
| Heat | Low | Moderate |
| 24/7 Raspberry Pi use | Excellent | Good: Possible, needs tuning |
I chose the RTL-SDR Blog V4 for its versatility.
HF direct sampling was especially attractive.
Click.
In the next post, I will show what happened after swapping the dongle. Unexpected results followed.
What happened next was unexpected.