No the one I purchased does not have an amplifier. There is another item “Active antenna” on ebay, which has this antenna plus an amplifier.
I was gonna say your 1m/3ft cable has probably around 1dB attenuation, comparable to 3m/10ft of LMR200/CFD200 cable.
Then i saw LMR1200, now that’s low loss cable: Termination of LMR-1200 cable - YouTube
Joking aside i’d still wish you’d test two antennas at the same time with different dongles 
(Swap the antennas between dongles after some time to exclude advantages of one dongle over the other)
But that would assume you have 2 more or less identical dongles 
Comparing it that way to a quick spider would be interesting, beating a mag mount antenna isn’t too surprising.
I ordered 2 pair of PCB-only antennas (without the tubes) from 2 different suppliers (both claim green PCBs) to see which arrives first (China vs Singapore).
The PCBs will be easier to fit in my box and I can experiment with modding/extending one for 978.
@abcd567 , where are your charts coming from? They look more detailed than the FA stats page.
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Current microSD card already has two dongles: One for dump978-fa, other for dump1090-mutability. This test cannot be done on it.
Testing two antennas at the same time with different dongles will require writing Raspbian image to a spare microSD card, installation of dump1090 (mutab or fa), and creation of 2nd instances of dump1090. Possibly will do this weekend.
PS:
Two instances of graphs, one for each dump1090, will also be required. How to do that?
I’d just use two RPis if possible, doing it on one is really annoying how the graphs are set up at the moment.
You could of course use a virtual machine, set up the graphs and change /etc/collectd/collectd.conf to point the URL at the 2nd dump1090 instance.
I can understand that you don’t want to interrupt your main RPi
But if it’s that much trouble, there’s no need, i’m already quite certain the antenna is about as good as the quarter wave spider.
What could be a bit better is that the VSWR seems to be going up quite a bit with lower frequencies, possibly filtering mobile phone frequencies a bit.
I just tried to replace my quarter wave spider on the roof, but the glue was much stickier than i suspected.
Maybe i’ll change my main antenna in the next couple of days though.
That would be a good comparison considering the longer time frame i think.
The test you posted today, was that with a regular dongle or an amplified setup?
Both the Mag-mount & PCB were directly connected to this one.
(includes an integrated filter, an integrated preamplifier and built-in ESD protection)
First mag-mount, then pcb for 20 minutes, then again mag-mount
Interesting differences between the table and window.
25% change in impedance
SWR is virtually the same
odd that S11 is worse.
(none of those measurements would stop me using it).
I suspect your window glass isn’t ‘just glass’.
Maybe very slightly tinted, but definitely not reflective from outside.
There were light showers sometime before I took measurements, and possibly the glass was still wet from outside.
Measurements of Parameters of a Mag-mount 1/4 WL Whip Placed over Cookie-can.
.
SWR vs Frequency
Unexpected curve. I was expecting a V shape curve, not Ripples.
.
SWR = 1.476, Impedance Z = 33.86 ohms
Removeable part of whip = 52 mm; hidden length inside base = 15 mm; Total length = 52 + 15 = 67 mm
abcd567, Is it by chance Low-e glass?
No idea. Looks like plain glass. The bulding was not built recently, so no chance of having very modern type of window glass.
I eliminated the USB cables that were close to the antennas and also moved the Raspi to the bottom of the box. The 3D printed Pi holder also has a section at the back for a DC-DC converter (haven’t wired it up yet). Plan to clean up the SDR mount.
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Oh you are bypassing the input protection of the RPi
(only available when powered via the dedicated mini-usb power port).
Good that you didn’t try the 6V power supply
My brother built one of my all-in-one boxes in Austin and is getting great reception with the DIY 1/4 wave antennas (box is mounted outside on a 2nd story deck) …
Antennas in opposite corners …
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Replaced the L-bracket with 2 small U-bolt plates. The Raspi is floating over the bottom of the box, supported by the USB connectors …
When your PCB antenas are due for delivery?
I went for one of those, sans enclosure, delivery can be as late as August.
I’m losing my enthusiasm for eBay. Deliveries from China are getting longer, and mishaps are becoming all too common.
I got my first set last Thursday (from China), only 1 week after I ordered them (I’m in the Dallas area) but as some have experienced, the ground plane leads were not soldered to the PCB. After fixing that, I put it on my impedance analyzer and the sweet spot was at 1160MHz (I think this freq is used on some intl FPV R/C plane transmitters) - the VSWR & impedance were both way, way off (don’t remember values).
I may try to extend one of them since 1160MHz implies it’s too short for 1090MHz. Otherwise I’ll wait for the other pair to arrive.
I ordered a pair of the PCBs in tubes today - figured I could cut the far end off and remove the PCBs.