Hi,
How about the best length for an indoor antenna ?
50mm, 100mm, 300mm or anything else ?
Thanks
For 1090 MHz:
From feed point (i.e. point where coax connects to antenna) to tip of antenna
= 1/4 wavelength = 67mm
.
(1) WHIP CUT TO 52mm
(2) USING COOKIE CAN AS GROUND PLANE
.
Do not want to cut the whip? No problem, replace whip by THIN steel or copper wire as shown below:
(1) WHIP REPLACED BY 52mm STEEL TIE WIRE
(2) USING FOOD CAN AS GROUND PLANE
4 Likes
HI, @abcd567
I’m going to whip cut and see if I got some extra gain.
Thanks a lot
PS: Very interesting the cookie and food can as bases for the antenna.
Using steel/iron base plate gives two advantages
-
The base of of whip does provide the essential part of antenna, i.e. ground-plane, but it is too small (one inch dia), and is grossly insufficient. The metallic cookie can or food-can sufficiently enlarges this ground plane and improves performance substantially compared to if the antenna is placed on wooden or other non-metallic surface.
-
The magnetic base clings to steel/iron plate, keeping whip vertical and prevents it from falling.
Better do NOT cut the supplied whip.
First try without cutting whip. Just place antenna over a metallic can. This alone will give substantial improvement.
Next, keeping base on metallic food-can, un-screw the whip, and use a thin wire as whip. You can use a wire longer than 52mm (say 70mm) and trim in steps of say 3mm and observe message rate/plane count/max range for say 10 minutes after each trimming. Continue till you reach 52mm.
2 Likes
I’ve tried with a spare whip, used for tv and, indeed more planes showed. Later on I’ll make a trial with a metalic base.
Thanks
the little antenna with replaced whip by a wire was my first antenna.
And it performed surprisingly well.
Indeed! I’m having best results, compared to the 170mm antenna that comes with the Flightaware blue dongle.
That’s a generic antenna. Can work, but not with the optimum
1 Like
This topic was automatically closed 365 days after the last reply. New replies are no longer allowed.