What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

on board radar, home brewed installation?

B

Blw2

Well Known Member
Wondering if any of the crafty home builders, in the spirit of the very crafty old time scratch builders, have ever done anything with a radar installation in a home built. Maybe using something from an old marine unit for example...

I was talking to a coworker earlier in the week about the radar in his boat.... a Garmin "dome" system. He was saying he can read seaweed floating in the water....pretty good system it seems.
Anyway I was thinking about this then....

and then Thursday night at the local airport's pilot association meeting, the discussion went to ads-b vs onboard radar, and the time delay.
and so I was thinking about a home-brewed radar install again...

Not something I'm trying to figure out how to do, just a curiosity.
 
"Big" jet wx radar gives you 80-120 miles, minimum. That's 10-15 minutes to make and execute the plan with ATC. Also helps keeps one 20 to 50 miles from hail and lines of cells.

Terminal area work- deciding to go or not or approach or not- there is way less margin for any mistakes.

Gain and tilt are as important as range- not sure which marine units could be adapted and how you would learn a unit's capabilities and limitations safely.

Shorter range than 40 miles, definitely under 20 miles, puts you at risk of hail thrown from storms. Playing close with cells and radar is also a great way to load up with ice and lose comms in p-static all at once if you cut it too close.

RVs cover 20 miles in under 10 minutes, possibly half of that- not enough time to make a normal plan, to me, and not enough gap from real cells to execute it.

I'm happy enough using ADSB wx in RV G.A. it's a bit over-presenting and shows movement and growth but makes one keep their conservative distance the more you see what even five to 20 minutes' refresh update delay can do to you. Like a storm scope, you see enough to avoid, but not pick a route fully without ATC's help.

Radar allows execution, ADSB-In wx allows avoidance. I've never flown monochrome radar or shorter range units- just modern-jet, 4 color plus, large dish stuff.

My opionion is real radar and real weather also means real ice protection.
 
+1 on above. Also remember the resolution depends on antenna diameter. Multi engine planes have a lot of ‘free’ space up front. For an RV, you’ll need a draggy antenna pod and it still won’t be big enough for good resolution. And these things do put out some power. Please don’t cook your dog, or a neighbor!
 
Also radar my miss inform you as it want show what is behind the line of weather ahead. You may think you see a thin area in a squall line with a area showing just alittle vertical movement and try to work through it when in reality it is so server it blocks the radar from its normal range. thus giving a false signal.
 
It is unclear to me if the OP was talking about weather radar, which Garmin has for GA aircraft, or radar to see other aircraft.

In any case, the real issue for a single engine aircraft is where to put the radome. Some have done wing mounted pods that end up adding about a 12” diameter frontal area. To get more effective weather data, an antenna plate diameter of 10” about min size. That is impractical for an RV.
 
I was thinking weather... but either way
and not necessarily limited to RV's....
...and not necessarily even have to be a successful thing...
meant more of a general question..."have you ever seen or heard of anyone doing it in the past...?" type of question

Anyway, good points about range and other considerations. All things about radar I know very little about. I just know that there are some very crafty and resourceful people in the world... going back to the spirit in the early days of homebuilt aircraft where they would use ...i dunno...sewing machine parts, bicycles, and lawn mowers to cobble together flying machines.... and so I was just wondering if ever have any of these type of folks done something...
 
I presume (since you mentioned ADS-B in your post) you are talking about a long-range aircraft detection system.

Let's see...installation may be a challenge (as is the power requirement, but that's another topic), and there would be a definite weight penalty to the system. OK...let's assume you manage that part and get an onboard radar working.

Operation: As someone who operated an airpborne radar (F-15s), I can tell you that there is a definite learning curve to the process, and even when proficient the time required to monitor such a beast can be enormous. We didn't call the radar display "the drool cup" for nuthin'! I'm not even sure that maritime radar system is useable in the air, as it probably simply looks at a single elevation and does not have an adjustable elevation control. Scanning the sky in front of you in a fourth generation radar system (I doubt you have access to a 5th generation electronically scanned system) requires a lotttttt of time--time that could be better used looking outside for traffic, monitoring your nav or motor, or drinking a nice cup of Joe.

Don't forget that radar sidelobe energy is dangerous; ionizing radiation from your wing will irradiate you and your passenger.
 
death ray?

While I don't recommend standing in front of an operating aircraft weather radar to keep warm, it is not "ionizing radiation". And the average power of airborne weather radars of my training (APS-42, etc) was about 25 watts. They operate at 9375 Mhz which is much less penetrating than your kitchen microwave.

The marine unit mentioned above likely puts out even less average power, so not a death ray. Receiver sensitivities are higher nowadays and less power is needed. Weapons related radar and jammer transmitters are another thing though. Don't ask me how I know.

I agree, the antenna/radome is a challenge. A twin could be made to accommodate a 24 inch phased array which would give a super picture. But as Bob said, a decent radome pod on a single might be pretty draggy.

Wing leading edge radomes following the normal wing contours with, then. mechanically phased elements go back to WW2. That type would be pretty easy now to do. It results in a vertical fan shaped beam that would be ideal for collision avoidance but not so hot for weather where a pencil beam to get vertical definition may be important.

ron
 
I am building an RV-14 that will replace the twin I'm currently flying which has a Garmin GWX-75 radar. Before I retired I flew a lot (300-400 hrs/year) in my twin for business. All single pilot. I depended on that radar and have fretted about having to give it up. I've come to realize that I simply will not need now that I don't have a schedule to keep and will be flying a slower airplane. Just one of those things you once depended on and don't want to give it up even though you don't need it anymore. Plus, landing and waiting things out may produce its own adventures.
 
Interesting question!

ADS-B nexrad on Foreflight, staying visual in the vicinity of nasty weather, and honoring the spirit of the underappreciated American genius Moses Rose seem to work for my kind of IFR flying.

Having "real" radar would presumably improve the scenario by opening up the prospect of flying in actual IMC in the vicinity of gross weather, but (a) It's hard for me to imagine a home-brewed system that I would trust to do that, (b) I think I would want FIKI to go along with that sort of activity, and (c) I'm sufficiently gunshy that I don't think I'd do FIKI in a piston-engine aircraft, period.

To me the more interesting home-brewed technology would be night vision.
 
moosepileit said:
Your searchlight would be of short range and small picture. If not using or covered by ATC WX radar assistance, stumbling into an attenuation type event, mentioned above would present differently than we see with larger antennae.

https://en.wikipedia.org/wiki/Southern_Airways_Flight_242

High chance of doing a Scott Crossfield.


https://www.aopa.org/news-and-media...tsb-releases-final-report-on-crossfield-crash
Click to expand...
The day Scott Crossfield bought the farm I was trying to get from Nashville, Tune to Raleigh - just a little hop over the hills. The Citation pilots who were briefing the same flight gave up and went back to their hotel. I decided to run under the cloud deck. I had to depart due South and was able to bend it around Southeast and then East later skipping from airport to airport and listening to AWOS along the route. It was pretty nerve wracking, especially at first, but the visibility never got worse than 3mi reported and the ceiling never below about 2k AGL. Crossed South of the mountains and North of Atlanta in improving conditions, picked up fuel in SC and cruised on up to Raleigh. Only heard about Crossfield that evening on the news. He went down maybe 50 miles North of where I crossed. It was a bad day to be flying IFR around there.

I didn't have ADS-B - nobody did then, tho I think Sirius XM was available - but I've used it since, VFR, to do some weather avoidance. Weather radar wouldn't have improved the experience. RVs are probably not the best planes to be doing IFR on convective days anyway.

Ed
 
This thread started back in September 2023. I missed reading it back then.

Having had a paying job working with RADAR and being a licensed ham, my concern about a homebrew RADAR for an EXPERIMENTAL airplane is how would one license the transmission of RF energy on a frequency or band when one creates this homebrew Wx radar?
 
You must log in or register to reply here.
Back
Top