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Would a new antenna really do better?

Started by mrschultz2, April 08, 2019, 09:32:07 PM

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mrschultz2

Just got a Flightaware Pro Plus stick and filter, hooked it up to the long wire antenna I have running along the peak inside my attic (somewhere between 20 and 25 feet) that I put in for shortwave listening.

I've seen messages per second as high as 800+, but it's normally in the 500 to 600 range.  Tracking out to about 100 mile radius, got some hills to the north west so low level tracking not great in that direction.  But I can track planes near KPHL (5 miles away) just about to ground level.

So, would getting a tuned antenna really do much better that what I'm getting from my long wire?  I'm not sure yet if I'm going to do this just for fun once in a while or get a Pi and set up something to run 24/7.

Big screenshot showing the typical traffic I've been seeing the last few days since getting the USB stick:
(Right click and view to read the text)

Anmer

Welcome.

It's difficult to give specific advice as 1090 MHz reception is influenced by so many factors - location, obstacles, antenna quality and height, coax cable quality and length of run, receiver quality etc.

Back in 2005 I bought a Kinetic SBS-1 which came with a magmount iantenna.  I placed the antenna inside the house and picked up two aircraft.  I then placed the antenna as high as possible in the room on a pizza tray and picked up around 10 aircraft, all within 50 mile range.  Next I tried a different antenna in the loft, using RG58 coax (all I had) and connected it to the SBS-1 with an "open" connector.  The number of aircraft and range increased again.

Eventually I invested a substantial amount of money for a mast mounted Elad antenna with preamp and 10 metres of 10mm diamerter Ecoflex cable.  The screen lit up and my range went to 260 nm.

My advice is to experiment with getting whatever antenna you have as high as possible.  If you're happy with the results, stick with it.  Or consider investing in better quality components.
Here to Help.

Truetrack

#2

Hi there
to be frank a horizontal and long wire for HF is not a solution   .
As Anmer described almost all went through the different different states of upgrading.
Here a few principles to guide you
- For 360 deg reception you need an Omnidirection Antenna, a Vertical.
- Ant as high, as free and unobstructed as possible. as local conditions permitting.
- Basic Models come as Ground Plane with disc or Radials,
  larger as collinear (multi elements stacked) as sticks, elements in plastic tubing.
  In their category they all get ~ 3.5 dB respective ~ 6.5 dB gain
- The Manufacturer each claiming 'Superior or Super Gainer' and what not.
You may have similar results with a homebrew when indoors.
There are many DIY 1090MHz Ant suggestions in the net.

Browse thru our forum Other topics Antenna Category for all kind of hints.
Regards
to give you an inital hints what possible
https://discussions.flightaware.com/t/three-easy-diy-antennas-for-beginners/16348/3
Klaus

mrschultz2

I did try a 1/4 wave antenna out the window, in the attic, etc., all those trials only got half the number of aircraft.

Right now I'm seeing 950 messages per second and 101 aircraft listed in RTL1090.  I guess I should just compare to the public plots and see if there are any planes I'm not picking up.

The horizontal long wire does seem to be picking up in every direction, I was kind of surprised by that.  What I'm seeing matches pretty well the horizon I should be getting.

This house is too tall for me to climb up and install anything up high on the outside.  So I guess I'll just try a few more configurations in the attic and see if they do any better than the current one that shouldn't work yet still does somehow.  At least the effort of running the coax up to the attic wasn't a waste, shortwave is not as fun as it was 40 years ago, but this plane tracking is kind of addicting.

Truetrack

Well if you decide against buying a manufactured one
and try some homebrew (most are simple, no loading coils or condensers)
here are the types to look for.

1/4 wavelength GP, horizontal plane or radials
1/4 GP drooping Radials, e.g. 4 each at 45 degs
1/2 folded GP, Element returning to 'ground'
5/8 Sleeve GP, lower portion is covered by a 1/4 sleeve

J-Pole, feed point is a bit hit and try
OSJ-Pole, Open Stub J-Pole, short and actv long element placed also parallel but each open
ended into coax.

and then there is a variety of Collinear Multi Element Verticals with e.g. 5 to 8 elements
often made with Coax sections. All are kind of hung within a plastic tube.
To a certain extent - more elements - larger reception range,
They require more effort and exact equal cutting of element sections.
but that does not mean they are improving on short distance down to Airfield Ground
Scroll down to search
http://www.hamuniverse.com/jpole.html
http://www.qsl.net/py4zbz/adsb.htm#e
Making an inexpensive 1090MHz ADS-B collinear antenna
http://www.qsl.net/py4zbz/adsb.htm#e

http://www.youtube.com/watch?v=TkUYdCPFXXs

BTW apply a polar plotter to give you the achieved distances.




Klaus

mrschultz2

I can't see spending money on a manufactured antenna if I'm only going to get a few more planes than I'm getting now.

The spider antennas look like they might be fun to build, so I'll try one of those tonight.

Then maybe I'll try building a colinear one, I've got plenty of RG6 around.


mrschultz2

#6
The collinear antenna looked like a more challenging build so I did that one, 10 segments just fit in the attic.

So far it might be working better for planes in the 0 to 50 mile range, and worse in certain directions out farther, the chimney of the house seems to be blocking this antenna worse than the long wire so there might be a larger blind spot to the north west.

I'll let it run all evening and see what the range plot looks like.

Here's a picture of it:



FYI, I used these instructions:  https://www.balarad.net/

Used a razor blade to cut the sections exactly to size.

Update: tried moving it closer to the side of the house but that made reception worse, so tried going the other way a few feet closer to the center of the house than I had it in that picture.  This seems to be the best location, getting coverage from Washington DC to NYC, and down to about 300 feet above KPHL (7 miles away).

So, looks like this is what I'll go with, thanks all for the tips.

mrschultz2

I tried a few more locations in the attic but the best one was the 2nd.
Went out and got a Raspberry Pi and installed PiAware on it, now with MLAT and the new antenna I'm probably seeing twice as many aircraft as before.

The traffic this morning (large image):