this is, WOW !


#1

I just moved my Rpi to the atic ,where i had already a home made GP on it.

each ring is 25KM ,so last ring is 200KM , i get atm data from planes OUT of that area.
While my testing area was on balkony, i had perfect view to the east, far in to germany ,but now i receive a 360 degrees area.

  • so happy with my litle toying now *

#2

WOW indeed !!

What is your antenna?


#3

simple ground plane ,with 8 radials, mounted on atic,
Antenna is made from high grade SAT cable, hot element is simply midle core of cable itself, and and radials are pieces of paperclip, sticked in shielding …
simple, easy, cheap, works perfect.

and ,uh, now comes the real fun part.i use a cheap TV amp.
dont have the stuff to get ON roof of atic, but i guess when i have my SAT LNA ready (PSU that is), signal should be much beter, and when i ever am able to get antenna on roof.
oh, i am also 190 meter or so above sea level, so ya, my house is on a prety high location.

ps.
Farest plane till now tracked, 390KM…


#4

It’s location, location, location! The higher the better for line of sight communications!

Great job!

–bob k6rtm


#5

ooh, i am not ready yet.
still working on my amp to get running, well.
as sayd i use a simple TV amp (25-950mhz) ,but performce still nice on 1090mhz
most SAT LNA’s work from 950 to 2200 mhz, but need 15V DC
bcouse my DC injector is for DVB-T, i need to mod the coil and de voltage (still stuck at the coil)
so the performance should go up when i get it work correct (hope asap)

still much to to here, but i am prety proud for my work and homemade stuff.


#6

In my case every ring is 50km, last one is 400 km


#7

wow, impresive.
you must be on a good location to.
well, i guess you have better gear as me… !


#8

Thanks :slight_smile:

Location is not bad, but in fact nothing special, average 5 floor building. This is how it looks from my roof.


#9

I just hooked up a cheap inline satellite amplifier (this one) which seems happy enough with a 12V injector (this one, amusingly the injector cost more than the amp), so it might be worth just trying with your existing injector and seeing if it works? The 15V figure is mostly a max value for passing the supply to the LNB as far as I can tell, between the LNB using voltage as a polarization control and whatever resistive drop they expect to deal with over longer cable runs, 12V is probably well within range for the amp.

Adding the amplifier and tweaking the SDR gain seems to have given me +20NM range (out to about the maximum I can reasonably expect - 200NM / 370km) and +20% messages … and some headscratching over dump1090 CPU use…


#10

Instead of hooking up all these preamps, consider plugging your dongle directly to antenna and use active USB extension to connect with PC. I myself use 20 meter long USB and it works perfect, no signal loss at all !


#11

hehe, yup, that the same amp as mine.
bcouse of high price on injector, i try mod mine.
and ya, the dongle gain is a pain to set, to high, and i see nothing, to low, i get less.


#12

Well…
i guess the big stick on the right is the adsb antenna
and as far i can see, much open terain, i gues even more as here.
i realy should try sneak on the roof and put a antenna on it…


#13

Correct, that stick is co-linear antenna made of 9 x 1/2 wave dipole elements.
You should definitely sneak on the roof and mount your rod there :slight_smile:


#14

i use a homebew GP here, bit to lazy to make a coco xD
but if the improvent is that high, wel, i can give it a try, got enough cable left here.


#15

Build the CoCo. I promise you won’t be upset with it. Take your time building it!

http://www.balarad.net


#16

to many designs found.
i found this, (what has good mesurments on lengt) http://f5ann.pagesperso-orange.fr/Antennecolineaire/index.html
and ofcourse http://www.balarad.net/

and as backup https://www.youtube.com/watch?v=TkUYdCPFXXs hehe
need to calc shortfactor on the satcable, but i recall it was 0.8.


#17

Try first with the easy one from youtube link. If it works well, you’ll consider making the solid one like this nodomainname.co.uk/Omnicolin … linear.htm I did exactly that way and it was worth it. Easy one took me an hour with almost no cost whereas the solid one required more effort and involved certain costs. The difference between both in terms of performance is only a couple of percent but every percent matters at least for me.

Have fun :slight_smile:


#18

[quote=“lankosher”]

youtube colo is based on the balarad design i just saw. xD


#19

The two most important factors seem to be
Height - to get the best unobstructed view to the horizon
Lack of interference from nearby transmission towers - like cellphone stations - filters can fix this, still looking for one at an excellent price.

The coco is a good idea, but it can be difficult to get an optimum design - If the velocity factor of the co-ax is not whats expected, and the elements are cut to the wrong length then the ‘sensitivity donut’ will tilt up or tilt down rather than just going out sideways from the antenna (I bought a bulgarian coco off ebay)

Your amplified simple antenna should be good for 220-240Nm (410-450km)


#20

i think that range is correct, dunno the math for nM vs km, but 360KM should be doable in good conditions.