LH0ezVT

cross-posted from: https://sh.itjust.works/post/34507515

How do you test your antenna idea? Well, our approach was to get a portable network analyzer that can show received dBm, put a commercial antenna on it, and strap the whole thing to a PVC pipe (for insulation and to get repeatable height). Then, zip-tie a cough drop to the PTT of a walkie talkie set to low power, so that it transmits continuously.

Now you can walk around your contraption with your Drain Pipe of RF measuring, and get a (rough qualitative) idea of how the pattern looks like. Much to my surprise, it actually worked.

How do you test your antenna idea? Well, our approach was to get a portable network analyzer that can show received dBm, put a commercial antenna on it, and strap the whole thing to a PVC pipe (for insulation and to get repeatable height). Then, zip-tie a cough drop to the PTT of a walkie talkie set to low power, so that it transmits continuously.

Now you can walk around your contraption with your Drain Pipe of RF measuring, and get a (rough qualitative) idea of how the pattern looks like. Much to my surprise, it actually worked.

Picture from a hike back in January. I need to go outside more often ;)

cross-posted from: https://sh.itjust.works/post/29055031

My first magnetic loop for 2m :)

Really simple construction: bent ca. 2mm brass pipe soldered directly to the outside of an SMA plug, inside of the plug soldered to the red wire as "input coil". Tunable by squeezing the ends more or less close together.

SWR of <1.2 at resonance, not bad. Impedance is at roughly 44+j2 Ohm, also not bad for totally eyeballing it without any prior calculations.

I can reach the nearest 2m relais just fine at 2W, although to be fair I can do the same with a short whip antenna. More testing to follow. Holy shit, this actually works!

My first magnetic loop for 2m :)

Really simple construction: bent ca. 2mm brass pipe soldered directly to the outside of an SMA plug, inside of the plug soldered to the red wire as "input coil". Tunable by squeezing the ends more or less close together.

SWR of <1.2 at resonance, not bad. Impedance is at roughly 44+j2 Ohm, also not bad for totally eyeballing it without any prior calculations.

I can reach the nearest 2m relais just fine at 2W, although to be fair I can do the same with a short whip antenna. More testing to follow. Holy shit, this actually works!

It will widen your horizon, they said. And here I was, foolishly thinking I could get away with half-assing statistics during my degree.

Turns out the status quo of Linux memory management somehow works pretty damn okay, nobody seems to really know why, and nobody cares.