Those are actually OKish antennas, a step above the typical mag-mount antennas anyway, and can easily be taped to an upstairs windowpane.They make decent starter antennas for those who don’t want to or can’t build a 1/4 wave ground plane (spider) or cantenna.
2 Likes
OKish is a good description. I use them not because they are good, but because they are consistent, so they make a good reference. Excellent to compare another antenna (at your location) to confirm it is better than just ‘ok’.
Has anyone used this 8.5 dBi Antenna from UK (Today’s price £49.80 = US $62.20 )?
https://shop.pimoroni.com/products/ads-b-1090-mhz-antenna-1-2m-8-5dbi?variant=31058778325075
Specifications
| Electrical | |
|---|---|
| Frequency | 1060-1120MHz |
| Bandwidth | 60MHz |
| Gain | 8.5dBi |
| Horizontal beam width | 360° |
| Vertical beam width | 9° |
| VSWR | ≤1.5 |
| Power handling | 100W |
| Impedance | 50 Ohms |
| Mechanical | |
| Length | 1.2m |
| Weight | 0.9kg |
| Connector | Type-N female |
| Mount style | Pole mount (clamps and mounting plate included) |
| Colour | Grey |
| Environmental | |
| Wind resistance | 100km/h |
| Temperature range | -40°C to 60°C |
I looked at this some time back
and found it only shipped to uk via ups and was silly amount
so i crossed it off my list
but seeing it today its also in uk now
1 Like
(1) Which was your previous aerial?
(2) The support on top of which your antenna is mounted, is it an ordinary pipe or some special mount?
Hi, my previous aerial was a 10 element Broadsword 1090mhz colineer vertical antenna which worked okay before the winds last year but bent in a storm and let in water. At the moment the new aerial is on the shed in the garden but will end up on the house in a few weeks. The aerial is connected to these parts.
6ft steel TV aerial mast- bulk: Amazon.co.uk: Electronics & Photo
1 Like
1 Like
thats the one lol 
1 Like
Don’t know if it was posted earlier, new model 11dBi. I might buy it and test it after the holiday season, compare it with my current COL1090/7.5-P.
2 Likes
WoW
Interesting . watching
I didn’t read this whole thread in detail, but building your own antenna is easy and a worthy cheap upgrade. See: WhiskeyTangoHotel.Com: DIY Antenna Improves RasPI ADS-B Reception Range
One of few sellers who are honest about Specs of their antenna. Truthfully declares Gain= 2.0 dBi
This type of flat pcb antenna suites indoor mounting, flush with window glass, and held in place by adhesive tape.
@abcd567 I am looking to up my game on DIY antennas - my 1/4 wave with 6 legs (ground plane) is working pretty well, but I’m intrigued by the thought of something more focused on the horizon (more “donut-y”). Poking on the threads, I see that previously you were making a “Franklin” spider
However more recently, it looks like you’ve moved on to the V-stub. I’m wondering if this indicates the V-stub is a superior design, or if you have other reasons for focusing on it now.
A technical question on the V-stub design (or Franklin as well, perhaps):
I recall seeing on one of the hundreds (thousands?) of posts I’ve dug though on antenna construction that the length of the ground plane legs for a spider should be about 1/4 wave - but a bit longer is OK (and better than shorter). I think going too long (1/2 wave) gave detrimental performance. I cannot find that post again, though (searching through all the old posts here is a fulltime job) - perhaps you know and can share the answer off hand?
Also I see in older posts on the Franklin you made some capacitor “hack” in a coax splitter body
But I haven’t seen that referenced in your later work - did that turn out to be superfluous?
Although theory and simulstion show Franklin Spider to be good one, none of the several proto-types I made, perform as good as expected. May be it required skill which I cannot provide with my fat fingures. However if I recall correctly, forum member @caius has reported that he had made one, and it was working as expected.
@abcd567 also - what about that capacitor in a “splitter” body you built at one point (for the Franklin); was that only for the Franklin design? It seemed intended for impedance matching, and it seemed to greatly help the Franklin, but I haven’t seen you reference it in anything since (1/4 wave, V-stub, etc.). Did that turn out to not be needed for other designs?
Based on this feedback, i think I’m going to try a V-stub next. Follow up question there - how critical is the spider leg length (I think I’ve seen 69mm and 72mm referenced)? Would you expect leg count to matter much?
Thanks
It is applicable to all designs wherever impedance matching is required, but it requires cutting and reterminating multiple times the coax, a trial and error method, and tedious, so I abandoned it.
It is not very critical, but better to stick with the one used in simulation, 69mm for 1090 MHz and 72mm for 978 MHz. Anyway if ou are interested to experiment, you can try different lengths (I did not try different lengths).
Leg count 4 or 6 or 8 dont make much difference. I have even used 2 legs in same plane as the V, so that antenna is flat and can be taped to window glass. You can try different number of legs and watch the difference in performance. Difference will be there, but not much.
If your goal is solid and guaranteed performance, go for a good commercial antenna.
If your goal is fun and experimentation, try various designs of DIY antennas.
2 Likes
@abcd567 Thanks for the feedback. Current goal is “fun experimentation”. For the cost of a COTS antenna, I bought a NanoVNA and some N-type panel mounts and will do some building.
Based on other discussion (I think from you previously even), as well as the web, I was under the impression that impedance matching wasn’t a big deal for Rx - and I’m a bit surprised that it made as big a difference for the Franklin as it appeared to for you. With a 1/4 wave spider antenna on some 75 Ohm coax, I’m getting pretty good results, so I’m hopeful that replacing it with the V-stub might squeeze a few more messages out of the ether. I’m optimistic the VNA can help me tune the lengths/angles to improve the VSWR and antenna impedance as well.
1 Like
Yes, I made one a long time ago when I was first experimenting with ads-b and using cheap satellite TV amps and filters. It worked pretty well and gave better results than the plain spider I made at the time. It wasn’t better than the Vinnant antenna I use now, though it wasn’t significantly worse either. They were only compared briefly in the loft before the Vinnant one was put on the roof however, so I would take that with a pinch of salt. I have no idea how it would compare with a better LNA and mounted outside.
I can only find one photo of it as it was installed at the time, lashed to a bamboo cane mounted on a lamp stand in the middle of the loft.
1 Like