How many birds does it take to change the SWR? This is just a bit of fun looking at the very small but consistent changes that a group of swallows make to the Voltage Standing Wave Ratio (SWR) on my home made 20 metre antenna. It’s not a scientific experiment but the results were, not surprisingly, reasonably consistent as it’s a well know fact that you can use capacitive loading to alter the characteristics of an antenna. I did toy with the idea of arranging bird food at the ends of the elements were their capacitive effect would be more noticeable but I didn’t want to encourage the crows as if they decide to land on the beam en masse as I think they would do more damage than just transiently shift the SWR! Thanks for watching, if you’re interested in radio you’ll find some hopefully interesting items amongst my other videos, there’s a No19 set, a Spy Radio, some vintage radios and the construction of the 20 metre beam featured in this video. Kind Regards …Andy gw0jxm
Video Rating: 5 / 5
A view birds! lol
Lucky that elephants can’t fly!
OK, I think you mean ‘A few birds!’
When we get a lot of birds they can be a bit overwhelming.
Kind Regards … Andy
Neat idea. RF is a very interesting study. Looks like the number of birds and the SWR is going to be very predicable.
Regards
Rick
Hi Rick
I looked, but I couldn’t find the section in the ARRL handbook that tells me the pf value for the different species, I think some of the buzzards around here are probably getting into the microfarad range!
Tell me, as a radio expert do you think I should get the Swallows to trim their toenails for fine tuning as I move up and down the band or should I just encourage them to ride the standing wave?
Kind Regards …Andy.
It might be easier to train a few of them to perch using one leg.
Regards
Rick
Now if we could just train one bird to pick up a long wire and place it high in a tree for us 🙂
I wondered if the brids stay off when your transmitting?
No, they don’t seem to mind at all
Regards … Andy
Hahahaha.. 🙂