Long Range Signals-West Coast of Ireland

[daithi-lacha]

Hallo,i was looking at the Planefinder app. lately and was amazed to see planes west of Ireland at 15 west!Does anyone know who the contributor is and where are they based.I thought my own coverage was good but this is unbelievable. Shannon radar has radar coverage out to about 16 west. I know this because i have seen the radar screen but i would like to make contact with the above Boxer to get a few tips. I am located near Cork Airport at 450 feet asl with my antenna at 40 feet wit an amp. feeding Andrews 7/8 inch extremely low loss cable. Also, on the Flightradar App, what does EGHQ2, NET2,LFPO2 etc mean.Are these code names of contributors. Thanks.

[CoastGuardJon]

Hi there, I'm situated sw Cornwall with standard antenna sat on a flat roof on an old brake disc, at a height of about 220'asl.   I'm on top of 190' cliffs with a clear view out west over the Atlantic. With this, I pick up to 13 or 14 degrees west depending on aircraft height.   I'm hoping to soon erect an SSE1090 and a Radar Extender, both about 13' feet higher, and will compare range plots, but I'm expecting the main improvement to be to the east, currently obstructed by our n-s gable ridge.   The main thing to get the best performance is height (with a pre-amp if a long co-ax run is involved) in the clear of obstructions as these 27cms signals are line of sight.   You already seem to have sorted out a good antenna system though, so possibly no more improvement possible easily.   Do you have obstructions around - trees, other buildings etc.?    HTH

[tarbat]

As I've stated elsewhere, I wouldn't trust the aircraft positions on planefinder.net.  They use prediction techniques to "guess" where an aircraft is positioned, rather than using actual position reports.  So, these aircraft west of Ireland at 15 west could be "guessed" positions.

See previous post at http://www.airnavsystems.com/forum/index.php?topic=6477.msg70651#msg70651

[daithi-lacha]

Thanks for that tarbat.I was worried that i had made a mess of my set up. That projection technique they use is cheating. I knew that it was impossible to get that kind of coverage. Mind you, i have seen the actual coverage of the newly installed Cork Airport radar that cost several million and my own Airnav can see almost as much! Serious. There shouldnt be any comparison between both systems really but i was gobsmacked. Their radome and my antenna are at about tha same height. Regards daithi-lacha

[daithi-lacha]

CoastGuardJon thanks for that reply.I can see the contrails of planes at 15 west when the sky is clear.I follow them as they pass over my house and i can eyeball them until Shannon tell them that they are at 15 west. I have to climb the mast to see them of course but if i can see them how come the coverage drops off at 14 west? Short of making a directional antenna ,it is proving hard to capture planes at the all important 15 west. I am experimenting with a ships radar rotator but i will have to devote more time to it given the frequency involved. Tricky stuff trying to keep contact while rotating at about 20 revs per min. My latest in fill project is a standard Airnav (home made) antenna on a ground plane (fixed)with a rotating parabola reflector. Dont  forget guys that the standard Airnav antenna that you get from Airnav is a top quality antenna. I cant see why this rotating arrangement wont work. Another thing i have tried is to put a dipole for 1090 inside the shell of a downlighter such as found in warehouses etc. These are excellent parabolas but it is crucial to get the correct focal point. Diameter squared divided by 16 times the depth of the dish/downlighter will get you the focal point every time. Im not a believer of buying antennas as they cost too much, and its more fun to make your own. The downlighter will give great gain but of course in one direction only!  Regards daithi-lacha

[bratters]

Very interesting stuff daithi-lacha and thanks for sharing it with us.  Please keep us informed of your progress and experimentation.

[CoastGuardJon]

Hi daithi-lacha, With reference to the rotator, these are usually driven by low voltage DC motors, if reduced voltage is applied, they slow down proportionately, just need to make sure power supply is capable of necessary current, or use potentiometer to reduce.   An electronic voltage controller would be the ideal, before the directional controller.   On the subject of your loss of signal at 15W, at that distance the contrail would have to have spread to be visible, and I'll bet the plane is actually over the horizon and no longer visible?

I've just re-read your post and see your experimenting with a ship's rotating radar sytem not a basic antenna roator, but you could use this as an incremental rotator with reduced voltage if DC powered, which I would assume is the case.

[daithi-lacha]

Hi,daithi-lacha here enquiring if there are any Boxers in the Cork City area. Thanks.