FlightAware Discussions

An Introductory Note About DIY Antennas

I laughed but with my more serious hat on, it does mention a supply voltage and an amplifier.

In case anyone is even considering buying this… don’t!

Damn, does not post to Germany :smile:

To be fair, it might just be a typo, it says 5Dbi, on a smaller picture and probably is fine for watching TV :wink:

Read the text now, there actually are active dvb-t antennas with inbuilt amplification, but they do not look like this, maybe someone copy-pasted different stuff together…

Yep…and digital, note the transitions.:rofl:

Hello everybody,

i started my little project on participating in the tracking network two days ago.
I am using a Raspberry P3 together with the FA Pro Plus stick (the blue one) and a simple indoor antenna which is for the 1090 MHz frequency range optimised out-of-the-box

All works fine with the FA Image. The receiver antenna i have placed on a cookie can (similar as shown above in my home office room on 2nd floor close to the window.

So far it is working, the range i usually get is constantly up to 100 NM with some peaks going to 150NM or 200 NM

The graphs are showing an average ADS-B signal level in average of -16 with a peak level of -1.2 over 24 hours.
Is there something to suggest for improving this except getting an outdoor antenna (which is currently not possible)?
Does the size of the can has an impact? Any thoughts on where at the window? Higher or lower?

I am living in Germany close to Frankfurt, so the peak number of aircrafts over the day is >100, in reality i’m ok with it.

Thanks

@foxhunter

Just to get an idea what maximum range you can get with an outdoor antenna:

What is the Maximum Range I can Get?

Even if the antenna says 1090 MHz, most of the time it’s not optimized for that frequency.
Almost all such antennas are falsely called 1090 MHz antennas.

For whip antennas, i haven’t encountered a case where the performance didn’t improve when cutting them to length:
How to improve performance of whip antenna of DVB-T

If you are using one of the nooelec antennas, those are very very bad. (unlikely with your range)

Thoughts on optimizing gain

Welcome to the hobby.

As @abcd567 said, you need an outdoor antenna to get maximum range.

If you look at the bottom of this page you will see your statistics and that of your 24 neighbouring Flightaware receivers.

Over a day you received 1,205 flights and 62,430 positions.

Over the same day seltsam (12 miles from you) received 3,924 flights

and

backi (who is 19 miles from you) received 845,103 positions.

If you have a good, external antenna that is not shadowed by terrain, buildings etc and your receiver/coax/filter/amplifier etc are appropriate you should be able to receive similar numbers.

Everything you compromise in the antenna/receiver/coax/filter/amplifier will reduce those numbers.

Have fun,

S.

Thanks for your input.

I thought already about the gain optimization, but unsure if this makes differencies.

The setting in piaware-config.txt says “rtlsdr-gain max” on the receiver configration. Is this the setting to be changed?

For the antenna i am mid-term planning to get an outdoor version, maybe DIY.
But we are close to a location move, depending on the new home i can mount it somewhere.

The antenna i am using is this one, mounted on a metal cake box:

@SweetPea11
I saw this already. I’ve set up my environment on Thursday evening with lots of experiments running through the house with the device and the antenna.
My wife already asked me if i took any kind of drugs :rofl::rofl:

Maybe the next project will be a DIY antenna, but this might take a while

I’ve had that exact antenna and built a whip of the proper length.
It’s not optimized for 1090 MHz, it seems everyone does this false advertising for the whip antennas.

You can either cut the whip or unscrew it and replace it with a piece of wire of the correct length.

Not significantly. Most of the mag base antennas are dubious at best. While they are quick to setup, they will be outperformed by just about anything.
In terms of height, higher is almost always better.

I’ve just left Frankfurt and writing from the ICE591!

You should be able to do a lot better than that. Have a look at the stats of your nearest

@wiedehopf

Thanks, never thought about that. I will check it, but before damaging it, i would rather try a DIY cantenna or something like that.

As i am close to EDDF (west of it) maybe that’s the reason why i am currently satisfied. Peak times show 100 aircrafts. What i do not get are aircrafts coming from east approaching, they are too low (or my antenna :stuck_out_tongue_winking_eye:)

Wow, saturday morning, many people woke up :slight_smile:

@geckoVN
Thanks for your input. Will try to improve. As stated, it’s a hobby and i like such challenges.

Forgotten to mention another funny fact:

If you look on the polar distribution where i got the most signal and the highest range is the opposite direction of the window where the antenna is located.

I would have expected that the view out of the window would be better than the opposite.
The antenna is “looking” towards EDDF and not westwards as the polar view looks like

Two of my receivers currently have an indoor antenna.

They are about 1km away from each other.

The yellow trace has a cut-to-length magnetic base antenna that came with a receiver dongle.

The red trace has a PCB dipole

It is quite a dramatic difference just replacing the mag base antenna.

It is a hobby for most of us. Welcome to the hobby.

It is also a global hobby. I am in Melbourne, Australia where is has just got dark on Saturday evening (1745 AEST, 0745 UTC).

The coverage map of all the Flightaware feeders is here.

S.

Sure, but i got up at 4am local time (due to our noisy neighbours) and not much traffic. Neither in the air, nor in the Forum.

Thanks for your suggestion. I’ve seen this antenna on eBay as well and i did not expect such a gain.
Will try it DIY first and then move to this one probably.

A quick spider is equivalent to the PCB antenna.
At least that’s my experience.

You can actually build a spider directly on the dongle if you want.
Similar to this antenna:
Three Easy DIY Antennas for Beginners

Yes, that’s what i thought about already
Maybe a project for a rainy day.

I just went up and move the antenna a bit. Even this gives a gain in signal and as a indirect effect longer range.

Looking forward for this DIY thing…

I was just running the small one liner from your wiki entry “optimizing gain” and it gives me this value:
"Percentage of strong messages: 7.804"

What do i do with this information now? any good or bad? What should i change from software perspective beside the antenna thing?
Or shall i start with the antenna first?

Advise on that is in the same post as the command.
If you have close by traffic that vanishes near you, reducing gain can help.
Right above the command is the link on how to change gain, does that link not work?

Changing the antenna you’ll have to have a look at gain again.

Yes, the advise is there, but maybe i have some issues understanding it, that’s why i was asking.

The close by traffic is stable and not vanishing, the trace is only interrupted the more far away the aircraft goes.

I think i leave this piece as it is and focus on the antenna first.

Thanks for your patient assistance with a noob having no idea what this is all about two days ago :slight_smile:

.

Trial Run Results for Three Types of Whip Antennas