So now it’s V-Lad vs Big Green Stick (FA 1090)…
Equivalent cables, radios, connectors, dump1090 settings, etc. Optimal gain was 44db for both antennas.
V-Lad:
Big Green Stick:
It’s V-Lad FTW!
DISCLAIMER: Once again, these results shouldn’t imply that there’s anything wrong with the FA 1090 antenna. It does imply that @abcd567 is very good.
Wow! The V-Lad blows the FA antenna away for your location. Not even close judging by the above. Thanks for running that comparison. Goes to show how location changes everything.
The radios already have a 1090 filter built in (after the amp but I can’t confirm) but I tried adding a RadarBox 1090 filter to the FA antenna but the results only got worse, even when I bumped the gain up by a few db to compensate for the insertion loss.
Hmm, i’d say either the filter is crap or there is something else wrong with your FA antenna.
I wouldn’t expect that much of a performance difference even to the DPD antenna, but really we don’t have good test data.
Might also be that you just got a bad apple, that would suck.
I can sweep the standalone filters later this afternoon but also remember, I’m in a very high out-of-band RF signal environment with FM and TV transmitters nearby.
Oops, just saw @abcd567’s post. I want to sweep the filters down in the 88-248MHz range.
No, it is NOT an ebay antenna. It is a single frequency (1090 MHz) antenna designed by me. Plese see design frequency marked in the simulation output below. The dimensions are in the in red rectangle on left of this screenshot:
Click on the image to see larger size Click again to see full size
Obviously if it doesn’t perform, it’s not interesting.
I’ve done enough computer simulations (CFD, FEI +) to know you need to validate your simulations.
If you build it and it works - then I’ll be impressed.
See @gtj0 posts and results above. His build of this model performed admirably for his location to say the least. His test methodology was sound - side by side tests. I usually take simulations with a grain of salt myself, but the real-world results shown above are tough to argue with. It doesn’t matter if someone uses a hubcap on a stick so long as it works…
I never presented the “Whip with Coil & Decoupling Sleeve” simulation and sweep results as a design intended to be built.
This simulation model was prepared exclusively to perform a very wide frequency sweep through computer simulation to see how such designs respond to various frequencies, as the title of that thread said, and that is the basic point you have missed:
Off Designed-Frequency Behavior of 2 Types of Antennas
Frequency Sweep (From 100 MHz to 2500 MHz) of Wire Collinear Antenna and 1/4 Wavelength Ground Plane Antenna.
Hi, what length of bottom V-Stub segment supposed to be if I want to connect it directly to coax and not Mag Mount? 62mm (as in post #4 diagram) or 62+20 (if counting base of Mag Mount)? Does it matter if it made from steel or copper wire?