Made yagi antenna with 5mm copper pipes on wooden reaper. Without aliexpress amp nothing worth. With the preamp it is picking some more ground messages. But not fully and also some times aircrafts vanishes and comes back.
Tracking site says 6 aircrafts are standing there (btw the site itself doesn’t track/show all aircrafts fully)
I have few doubts regarding folded dipole on yagi. I am presently using two cut pipes as driven element one for + and other for -. Using cut pig tail cable with connector to connect with inline amp (50 ohms cable I think) and then on the amp output using another pig tail(50 ohms) and connecting it to RG6. Which then runs for around 40ft to the Nooelc mini dongle.
I don’t have 50 ohms cable. Will there be any chance of improvement in reception if we use folded dipole? What should be the folded dipole length?
I am not able to find the calculations for it and hence I just cut DE element into two as an interim arrangement.
Antenna I made with wooden reaper. Copper pipes 5mm diameter with 15 directors (1326mm).
Site used for calculation: VHF/UHF Yagi Antenna Design - K7MEM
The quality of that amplifier is most likely the most limiting factor if the yagi works well.
What is your reception range with the yagi currently?
(compared to your FlightFeeder)
Initial tests showed that it was able to get 50NM more than FA antenna towards that direction. FA antenna was 20ft above this antenna! In another direction when Yagi was pointed, it was picking up low altitude flights around similar 50NM range before FA picked which was 20ft higher picked it. But I will try to increase the height of this Yagi and will compare side by side and will let you know.
What voltage are you feeding to the amplifier? It’s indicated on the product page 8-10 V is the optimum.
What you are trying to do is really hard.
That’s very nice, means that it’s working but the airport is just too much out of view and it might just not be possible to get good reception from the airport.
I found 6V to be optimum voltage. If it is increased to 7.5 or decreased to 4.5 then dump1090 is not decoding any aircrafts or decodes very few.
Manual gain at 38-40 seems to be best. AGC some times works better and some times worse.
My terrace is flat roof. So keeping the Yagi here and there picks some places of runway/ramp but not all. It is like some 2-3 places which covers some part of Airport. Offcourse not everything will be coming and only some strong signals might be coming.
In Jetvision blog they have mentioned that they live 30kms away and used their 27 element yagi to get ground traffic from Munich airport. There will be some buildings in between them and the airport. Still they are managing. So I thought to try. Quality of their antenna can’t be compared with mine but my distance maximum is 5-6kms.
Thousands of default configurations are using AGC myself included. If FA thought AGC did not work than they would include user interface to change/optimize it.
For instance yesterday evening I was receiving over 160 aircraft with positions. Positions per second were over 1100/sec. My RSSI less than -3 was less than 10%. I normally don’t do this well but am proving a point that AGC does indeed work, maybe not as well as an optimized gain but until FA gives me that optimization tool it will remain AGC. My guess is that FA doesn’t really care about this issue at all, so neither do I.
With “doesn’t work at all” i’m saying it’s a fixed setting of 55 most of the time, not actually automatically changing gain.
Of course there are situations where using a gain of 55 works just fine.
For example when there are no amplifiers involved.
With a Flightaware Pro Stick Plus at -10 (AGC) and an FA antenna on the roof with the cable being quality and less than 5m you will lose planes that fly at 5000 ft AGL and less than 10 miles away.
You will likely have gaps in your track.
People with their antenna at the airport need to change the gain if they want to actually observe aircraft at the airport.
Now there are occasions where there is a constant noise producing large enough signals for AGC to actually change gain.
So in that case it can be actually changing gain.
Well it’s likely you have interrupted tracks on your local maps for low flying traffic closer than 10 miles.
If you don’t mind that, then great, no need to change gain.
As for the optimzation tool, FA provides their stats.
You can run 49.6 for a week for example and then compare Monday with the previous Monday and check the position count for each range.
If you gain something for every or almost everyday, then the gain is better.
That’s a great optimization tool.
I guess that brings us to what is an “optimization tool”. I am thinking long term so maybe query the SDR and get what gain settings are possible. Set a schedule for each gain setting to run say for a week then move to the next gain setting and sit for another week, (wash, rinse, repeat) etc, etc.
Provide consolidated stats on webpage (skyview?)
Maybe assign a score to each gain setting.
Should be accessible via gear menu like Syview.
No downloads or command line needed/wanted.
User selectable gain is then used by app.
Should have an “auto” mode for the very faint of heart.
No other setting gets as much press here as gain yet it remains a mystery to most users.
No other setting has a much potential of increasing both the accuracy of the data as well as the scope of the data collected. It too will be ignored by too busy staff.
I also note the great work on gain done by some of you was completely ignored in the latest release. Disappointing to say the least.
hi bob, i’ve been at this for a year now and i’ve spent more time with gain than any other topic or issue. if only the weather and airline schedules and seasonal foliage etc., would cooperate and provide us with a constant input (even if it were every monday the same, every tuesday etc) then setting the gain would be easy. since we can never guarantee a constant input level we can never fully optimize the gain.
I decided to test for an overloaded front end (as best as I could) so I sorted by RSSI with the strongest at the top of the chart. I then came back to the map view and watched the message count of the just sorted high signal strength aircraft. We have helicopters flying around the Falls and Lower Niagara (less than 8 NM). Usually there at least two in the air at all times. That didn’t help because there is too much swapping with transitioning aircraft going to Toronto overhead. So I sorted on map view for closest and watched the age. Didn’t see any that even had a 1 nevertheless a 2 second age.
SOOO, I do not know how to do this because in the RSSI view we constantly have signals < -2.0 but it still reports the message. I think that < -2 is an overload but it still reports. So how big is too big?
Well you can only speculate on message that were too strong to be received.
You can’t receive messages stronger than about -1.5.
Messages stronger than -3 are counted as strong messages.
So if most aircraft you see are at -2.5 you have lots of strong messages but you might be receiving all of them.
It’s likely though that you are missing at least the stronger messages sent by those aircraft.
Signal strength varies quite a bit.
You can’t detect overloaded message well, that’s why you estimate the overload by counting the messages that are not quite so strong that they are overload.
There are quite a few threads about gain, if you want to understand it, it should be possible.
(one of the threads: Thoughts on optimizing gain)
But i can appreciate that really understanding the issues around gain requires quite detailed knowledge of how the receiver works.
Many people seem to want some automatic adjustment of gain.
And while it might not produce the optimum result, it should work reasonably well in most situations.
I carefully watched a flight come in to Niagara Falls, paying close attention to dotted track. I did notice on two occasions where the dotted lines happened and can only be explained by overload of front end as they happened within 10NM of my location.
Ahhh, the ultimate ADS-B receiver. Maybe some enterprising person would like to step up and make a little money on the side. But not me. sounds like too much work for this hobby and for marginal gain (couldn’t resist )
Yes, at Nigra Falls 2 to 3 helicopter circling is a daily routine. I get them from Toronto easily (aerial distance about 30 nm), both at 1090 mhz and 978 mhz.
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