Recent content by galenthurber

may be because your stub is not tuned, recheck ab cd 's drawing

welcome to homebuilt antennas, my best is a horseshoe https://forum.planefinder.net/posts/8231/

a thing of beauty

This has happened twice I noticed, is Moscow the default start point?

rehabilitation of an UT108(1) has failed. It's a roller coaster SWR vs freq with little to no chance of tuning 1090Mhz the range is poor with spotty reception around 50nm

225nm and it's not even in a good position, it's next to aluminum siding

after trimming the UT108's top down to 175mm measured from the top of the coil, the readings are are barely changing. anyone wish to estimate where the next low SWR point will be ?

ran a SWR test at a limited frequency range below 520Mhz 514,7.8 512,7.6 510,6.8 508,5.2 506,2.9 504,2.2 502,2.2 500,2.9 498,4.9 So I'm guessing the tuned frequency will be 1008Mhz (roughly, could be off due to capacitance) and SWR 1.6. Antenna top is too long, needs more trimming to match RG58...

yes that's the type, mine is inverted. My equipment is limited to testing the SWR at frequencies below 529Mhz. mhz swr 515,4.7 512,5.1 510, 7.1 but I'll need more data points inorder to fill in for the missing arm of the complex parabola. The good thing is that the best SWR is above 515Mhz, so I...

also at 1080, 1087.2, 1094.4Mhz etc (nasty)

My Nooelec SmarT has birdies / internal noise spikes at 1080, 1087.2, 1094.4Mhz etc (nasty) So it is poor for tracking 1090Mhz ADSB signals. If you own one of these SDRs and are feeding check it for these reception killing internal spikes.

ALSO I switched SDRs. Now using Nooelec SmarTee, instead of Nooelec SmarT which has birdies / internal noise spikes at 1080, 1087.2, 1094.4Mhz etc (nasty) My SDR gain for feeders is at manual, max. So ...

early results are quite promising. Instead of the meat of collected data was spotty & below 50nm now it is 50-100nm, tracking now has solid tracking out to 125nm. Spikes up to (polar plot pfclient reporting) 225nm

Just built an ugly horseshoe antenna; it works. it's a smaller version of a 145Mhz one. each arm (L shape) has 1/4wave horizontal & 1/2wave vertical. The antenna is fed where the open end of the horizontal element arms almost touch; 10mm apart. The feed line must come in at 90degrees to the...