======Spiral loop 40M======
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Specs:
|Manufacturer|Tonnie ;)|
|Type|Spiral loop 40M|
|Operating frequency|7MHz, 14MHz, 28MHz|
|Gain|Typical 2dB|\\
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Built this antenna according to [[https://www.nonstopsystems.com/radio/frank_radio_antenna_SM0VPO.htm|NonStopSystem's plans]] as an experiment. Has some interesting results, I must say.\\
{{::sl40m_7mhz-7.2mhz.png?400|VNA test at 7-7.1MHz}}\\
Not really promising, but then again, it's a test loop. The capacitor for the tuned loop is a PCB type, and it needs to be bigger because I don't reach capacitance yet. Scanning a range it shows a nice but unexpected story:\\
{{::sl40m_1mhz-900mhz.png?400|VNA test 1t 1-900Mhz}}\\
It has resonance on some other interesting frequencies, let's dig a bit deeper:\\
{{:sl40m_144mhz-146mhz.png?400|VNA test at 144-146MHz}}\\
At 2M it's SWR is at 4.5, not great but better than the Nagoya. Another dip is observed, let's see the 70cm results:\\
{{:sl40m_430mhz-440hmz.png?400|VNA test at 430-440MHz}}\\
Pretty resonant with the center band at SWR 1:1.5...\\
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Conclusion:\\
Might not be my go-to when I start hitting the HF bands, but surprisingly performs quite OK on 70cm.\\