Avionics Ground Bus kit

I'm pleased to announce a new product I developed for aircraft electrical systems.

It's called the AGB-1 Avionics Ground Bus, and it's a way for you to reliably and easily consolidate your low-amp avionics and lighting grounds in one place behind your instrument panel. Several well-known avionics experts advocate this type of remote ground bus.

After attempting to solder long bare wires to the back of a D-sub socket (a popular option in some circles) I realized that even with 35 years of experience soldering electrical components as a hobbyist, I simply could not trust my life to the connections I'd made using that method. I also looked at some rather scary ground buses that were actually built and installed in some people's airplanes. I decided that modern homebuilt airplanes (especially IFR-capable ones) deserve something far better - something that will give you not only ease of building, but reliability and piece of mind.

Over the past six months, I developed the AGB-1, and now my buddy Kevin and I are offering it to the homebuilt market. We've been told by our Beta testers that it's a vast improvement over other solutions that are avaiable.

It's available exclusively through our website at www.AvionicsGround.com. We hope you like it.

load capacity?

Hi Buck,

This seems like a tidy package, and would probably really simplify connecting the many grounds from headset and mic signals, and other low-power devices.

But with the PC-board foil as a way to carry loads to ground, and just two 14-gage wires to take all the loads to ground, I'm wondering what the actual load capacity would be. There are lots of things I have tied to ground that each have 14 ga and 16 ga conductors, carrying a few amps each. Is it OK to ask a pc-board foil to carry a 75W lamp load (6 amps)? What about an autopilot servo? Flap motor? A handful of these sorts of things and before you know it, you've got 25 amps going to ground through your 14 ga conductors???

Not sure how to get shields tied together around the whole package so it doesn't become a noise source? Most radio installations specify that the shields are grounded at the radio case and are floating everywhere else. I wonder if it is OK to ground all the shields at your box, and have the shields float at the radio and intercom as well as at the phone and mic jacks?

scsmith said:

Hi Buck,

This seems like a tidy package, and would probably really simplify connecting the many grounds from headset and mic signals, and other low-power devices.

But with the PC-board foil as a way to carry loads to ground, and just two 14-gage wires to take all the loads to ground, I'm wondering what the actual load capacity would be. There are lots of things I have tied to ground that each have 14 ga and 16 ga conductors, carrying a few amps each. Is it OK to ask a pc-board foil to carry a 75W lamp load (6 amps)? What about an autopilot servo? Flap motor? A handful of these sorts of things and before you know it, you've got 25 amps going to ground through your 14 ga conductors???

Not sure how to get shields tied together around the whole package so it doesn't become a noise source? Most radio installations specify that the shields are grounded at the radio case and are floating everywhere else. I wonder if it is OK to ground all the shields at your box, and have the shields float at the radio and intercom as well as at the phone and mic jacks?

Click to expand...

In defence of Buck, he says "reliably and easily consolidate your low-amp avionics and lighting grounds". He doesn't imply that all of your avionics could (or should) be connected with such a device.

It certainly has a role in distribution of low-current grounds, however, Fast-On tabs are the way to go for high-current devices.

We've done something similar at Vx Aviation, and we recommend the same thing "low current grounds or power distribution".

A perfect example is what Buck recommends... lighting buses. Use one for lighting grounds, and one for lighting power distribution.

Vern

Buck,

Nice job on a product to make wiring easier for people!

Looks like the d-sub connector is mounted upside down, though. Do you simply put wires in the connector with no way to secure them? I assumed you would run ground wires into a d-sub connector with a shell and then plug that into your box, but it doesn't look that way from the picture. What am I missing? Didn't see anything on your site showing a completed installation. Thx.

Hi Folks,

Thanks for the inputs. We definitely and clearly state in both our website and our assembly manual that this type of ground bus is to be used for low-draw items such as EFISs, EISs, instruments, nav radios, intercoms, LED lighting, and the like -- not flap motors, pumps, solenoids, comm radios and other higher-amp items. Basically, anything that uses a 20 AWG ground wire or smaller is OK. A total load of 20-25 amps for the unit is fine.

If you're familiar with Nuckolls' book, this product is suitable for use as the remote avionics ground bus that he features in his Z-diagams. D-sub pins are rated at about 3A each, and anything larger than that should be routed directly to the aircraft's central grounding point.

The goal of the AGB-1 is simply to provide a reliable way to make the smaller connections using a PC board -- instead of what, inevitably, turns out to be a big solder-blob on the back of a connector. Vern's also got a nice solution to this issue.

Intercom (mic/headset) grounds should be wired as specified by the maufacturer, in order to minimize the chance of gound-loop noise.

MCA said:

Do you simply put wires in the connector with no way to secure them?

Click to expand...

Hi Mark,

You are indeed looking at the back side of a male connector. It's permanently mated to a female PCB connector inside the case. When you're wiring your panel, all you do is crimp a male D-sub pin on each of your low-current ground wires, push each one into the connector, and they click into place. An extraction tool is used if you need to re-position or remove a pin later.

I'll try to get some photos of a finished installation on the site on the next few days.

Just as an FYI to add to this...Buck sent me one of these kits to review. It indeed is a VERY complete kit (yes, you still have to do some minimal work, but you are building and airplane after all). Indeed you won't be running high current stuff through it, but then again it wasn't designed for that. For what is designed for it is a very elegant little package.

Add to it that they seem to be taking John (from smoking airplanes) lead and providing a kit with every little piece you will need in order to utilize this device. Packaging is good, and so is the very thorough and detailed manual - complete with pictures and easy to follow instructions. Consider this my endorsement. For now Buck is going to sell these direct and I think that is a good thing. What I'm saying is it's good enough for me to sell!

Lastly, don't forget that Buck is one of us, although I am frequently jealous that he gets to play with some really cool planes without props!

My 2 cents as usual.

Cheers,
Stein

Concept diagram

I've had some questions regarding how the AGB-1 is to be used as low-amp remote grounding point, so here's a diagram that I hope explains the concept:



If there are further questions, I'll certainly try to answer them as clearly as I can. I'll also get some photos up shortly. Thanks to everyone for their interest!
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