Cheers.
Web SDRs take away the electronics side of the antenna hardware which is the fun part.
I am surprised how expensive the commercial telescopic whip is:
https://www.hamradio.co.uk/aerials-a...hz-pd-7829.php
My 5.6m telescopic whip is cheap and it is robust. Probably it is not much different from the expensive one. It is much cheaper to DIY it. At its full extension, the resonance frequency is 13.5MHz with a quarter wavelength of 5.6m. All I need is a DIY loading coil with tappings which can be just a crocodile clip with this calculator to cover frequency below 13.5MHz:
https://www.66pacific.com/calculator...alculator.aspx
Add a PVC pipe extension and a camera tripod, it saves £440.
This web page contains a simple Excel calculator for passive tuned loop design for transmitters. For receivers, it is not necessary to use thick copper pipe to miminize power losses due to skin effect.
http://www.aa5tb.com/loop.html