Another strange day in the little yellow Vag-A-Bond

Shepherd

Shepherd

Final Approach
Joined
Nov 24, 2012
Messages
5,424
Location
Hopewell Jct, NY
Display Name
Display name:
Shepherd
Yesterday was my first test flight after a long (3 months and 7 days), very expensive annual.
The plane is fine, it flies great.
But apparently my mechanic added stealth technology to the plane.
I am no longer visible to the radar at my home airport.
Flying a straight in approach from 10 miles out, starting at 4,500 ft, they insisted they could not see my clothe covered, metal framed airplane on radar.
This is now the 3rd airport where this has happened to me.
Any radar experts out there with an explanation why this is happening?
I really don't want to put in an electrical system, just so I have a transponder and adsb.
 
It’s likely caused by signal filtering by the receiver or software. You could build simple RADAR reflector to boost your RCS to overcome any signal filtering.
 
Shepherd said:
Yesterday was my first test flight after a long (3 months and 7 days), very expensive annual.
The plane is fine, it flies great.
But apparently my mechanic added stealth technology to the plane.
I am no longer visible to the radar at my home airport.
Flying a straight in approach from 10 miles out, starting at 4,500 ft, they insisted they could not see my clothe covered, metal framed airplane on radar.
This is now the 3rd airport where this has happened to me.
Any radar experts out there with an explanation why this is happening?
I really don't want to put in an electrical system, just so I have a transponder and adsb.
Click to expand...

no transponder or adsb you say? They may see you as a primary target but without a data tag they can’t decipher anything about you. Therefore they don’t know who or what you are.
 
Oh my gosh, the controller will need to look out the window and maybe use their binoculars. The old guys have no problem doing this, the young guys - I'm not so sure.
 
Shepherd said:
Yesterday was my first test flight after a long (3 months and 7 days), very expensive annual.
The plane is fine, it flies great.
But apparently my mechanic added stealth technology to the plane.
I am no longer visible to the radar at my home airport.
Flying a straight in approach from 10 miles out, starting at 4,500 ft, they insisted they could not see my clothe covered, metal framed airplane on radar.
This is now the 3rd airport where this has happened to me.
Any radar experts out there with an explanation why this is happening?
I really don't want to put in an electrical system, just so I have a transponder and adsb.
Click to expand...
And this started just after the Annual? What are the 3 Airports? Are they all in the same Approach Control's airspace using the same Radar.
 
Last edited:
Arnold said:
Oh my gosh, the controller will need to look out the window and maybe use their binoculars. The old guys have no problem doing this, the young guys - I'm not so sure.
Click to expand...

10 miles out in a cub? That would be difficult to see even with binoculars
 
luvflyin said:
And this started just after the Annual? What are the 3 Airports? Are the all in the same Approach Control's airspace using the same Radar.
Click to expand...
This has been going on since I got the plane.
Danbury (KDXR) and Lebanon (KLEB) were the first two airports where this happened. That was pre-annual.
I've never had this happen at KPOU until post-annual.
I really don't car, it's just weird.
 
Timbeck2 said:
no transponder or adsb you say? They may see you as a primary target but without a data tag they can’t decipher anything about you. Therefore they don’t know who or what you are.
Click to expand...
He said he was talking to them. @Shepard , how did things happen before the Annual? Did you call requesting Radar Service and they would identify you and say 'Radar Contact?
 
luvflyin said:
He said he was talking to them. @Shepard , how did things happen before the Annual? Did you call requesting Radar Service and they would identify you and say 'Radar Contact?
Click to expand...

With no transponder I never bother asking for flight following or radar services.
What typically happens is I call in to announce I'm in bound and then I spend the rest of the down hill ride answering where I am and my altitude until I get 2 or 3 miles out and they can eyeball me out the window.
 
Shepherd said:
This has been going on since I got the plane.
Danbury (KDXR) and Lebanon (KLEB) were the first two airports where this happened. That was pre-annual.
I've never had this happen at KPOU until post-annual.
I really don't car, it's just weird.
Click to expand...
Ok. All towered Airports. So I assume you are just talking to the Tower. It's possible POU and DXR are getting their Radar from different Radar Antenna's. I can think of nothing that could have happened to the plane that could cause this unless a metal prop was replaced with wood or their was something reflective in the plane that they took out. Maybe they made some change to their Radars and the timing with your Annual was just a coincidence. Temperature Inversions can affect Primary Radar returns. Another possibility is a Controller/Technicion pushed some wrong buttons inhibiting Primary Radar on his scope.
 
ATC radar operates in the 2.7 GHz to 2.9 GHz frequency band, which is just below S-Band which has a low end at 2.9 GHz. A passive marine radar reflector that covers X-Band as well as S-Band installed inside the fuselage behind the passenger cabin should light you up on ATC radar. They usually sell for around $350 and weigh about eight pounds. The Echomax 230 should work for you; it's cylindrical, 24" tall and 10" in diameter.

Echomax EM230BRM 24 x 9.65 in. Passive Radar Reflector - SOLAS & MED - Walmart.com
 
Shepherd said:
That's the only thing that's been removed from the plane, so.........
I would have thought my new stainless steel exhaust system would blind them from afar.
Click to expand...
Well gee. There was a Radar Reflector in the plane and they took it out? I dunno about different reflectivity of different metals. I doubt it matters here. But size and shape can have effect
 
Not so many control towers or so much radar at little grass strips. Just sayin'.
 
Stan Cooper said:
ATC radar operates in the 2.7 GHz to 2.9 GHz frequency band, which is just below S-Band which has a low end at 2.9 GHz. A passive marine radar reflector that covers X-Band as well as S-Band installed inside the fuselage behind the passenger cabin should light you up on ATC radar. They usually sell for around $350 and weigh about eight pounds. The Echomax 230 should work for you; it's cylindrical, 24" tall and 10" in diameter.

Echomax EM230BRM 24 x 9.65 in. Passive Radar Reflector - SOLAS & MED - Walmart.com
Click to expand...


That seems a bit pricey and heavy. Inside the plane a reflector won't need the wx protection it needs exposed on a boat at sea.

One of these
https://www.defender.com/product.js...MIkO-mh_fY-gIVUMqGCh1p4ggTEAQYBSABEgLr1fD_BwE
would probably do as well.
 
Half Fast said:
That seems a bit pricey and heavy. Inside the plane a reflector won't need the wx protection it needs exposed on a boat at sea.

One of these
https://www.defender.com/product.js...MIkO-mh_fY-gIVUMqGCh1p4ggTEAQYBSABEgLr1fD_BwE
would probably do as well.
Click to expand...
I saw that, but don't know if the surface area is big enough for S-Band, which is much lower in frequency (longer wavelength) than the prevalent marine radar which is X-Band (8 - 12 GHz). Maybe something similar to the Davis reflector, but with larger diameter discs.
 
Last edited:
Stan Cooper said:
I saw that, but don't know if the surface area is big enough for S-Band, which is much lower in frequency (longer wavelength) than the prevalent marine radar which is X-Band (8 - 12 GHz). Maybe something similar to the Davis reflector, but with larger diameter discs.
Click to expand...


Well, S-band is about 12cm max wavelength, and the radius of that reflector is about 15cm, so that seemed to me like it should work okay, but I'm not a radar geek.

It'd be pretty easy to make a larger one to play with, though. Three discs cut out of cardboard, covered with Reynold's Wrap, and slotted so they'd slide together, held together with a little tape.
 
TCABM said:
It’s likely caused by signal filtering by the receiver or software. You could build simple RADAR reflector to boost your RCS to overcome any signal filtering.
Click to expand...
We used these in offshore fishing so bigger boats saw our profile and didn't run us over when we stayed overnight 60 miles offshore in the canyon very effective
 
If they removed a Davis reflector and they could see you before, I'd just buy another and put it back in.

The name of the game is having a big radar cross section, and the attached 2007 test shows the Davis scored poorly compared to other more sophisticated reflectors. The test was financed by the UK government Marine Accident Investigation Branch.
 

Attachments

  • Radar-Reflector-Test-2007.pdf
    1.4 MB · Views: 1
Whoa… I’m exhausted. Trying to follow posts like these make me forget ALL my troubles. Freakin hilarious. Just wanted to say thanks!
 
Stan Cooper said:
ATC radar operates in the 2.7 GHz to 2.9 GHz frequency band, which is just below S-Band which has a low end at 2.9 GHz. A passive marine radar reflector that covers X-Band as well as S-Band installed inside the fuselage behind the passenger cabin should light you up on ATC radar. They usually sell for around $350 and weigh about eight pounds. The Echomax 230 should work for you; it's cylindrical, 24" tall and 10" in diameter.

Echomax EM230BRM 24 x 9.65 in. Passive Radar Reflector - SOLAS & MED - Walmart.com
Click to expand...
Could you do the same thing by wrapping aluminum foil around a cardboard cylinder? Duct Tape, aluminum foil and cardboard are way less expensive if they would work. What do you radar experts say? Will it work?
 
William Pete Hodges said:
Could you do the same thing by wrapping aluminum foil around a cardboard cylinder? Duct Tape, aluminum foil and cardboard are way less expensive if they would work. What do you radar experts say? Will it work?
Click to expand...
Not an expert, but a corner reflector will give back a much stronger reflection than a cylinder which will, essentially, just reflect back along a fairly narrow line.

 
Capt. Geoffrey Thorpe said:
Not an expert, but a corner reflector will give back a much stronger reflection than a cylinder which will, essentially, just reflect back along a fairly narrow line.

Click to expand...

This is a really good video. Shepherd, you could build a corner cube reflector from 4 cardboard boxes with aluminum foil on three internal sides. 2 sides and the bottom of the top. I would think 8 x 8 would be good enough. I imagine you could build it for about 10 bucks if you got used boxes from a grocery store.
 
You must log in or register to reply here.
Back
Top