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When the Customer Is Not Right

A yagi antenna with a specific frequency range can't be used as an ultra-wideband antenna.

A yagi antenna with a specific frequency range can't be used as an ultra-wideband antenna.

Is the Customer Really Always Right?

In my workplace, a common joke is: “Just let me know which laws of physics you want violated, and I'll work you up a budget.” This quote is originally attributed to a NASA engineer.

I asked the chief engineer how often we received requests that actually violate the laws of physics, and he said, “For the consulting projects, about once a week.” In a review of our most recent consulting projects, I found he was right.

Common Requests That Violate the Laws of Physics

A periodic request we receive is a design project asking for an antenna much smaller than what could conceivably handle the frequencies they want to receive. In one case, someone requested an antenna design for an antenna with the gain of a 10-foot dish in an antenna the size of a postage stamp. You can have an antenna the size of a postage stamp or the gain of a ten-foot antenna, but you cannot have both. There are times when an array of small postage stamp antennas is the solution.

The frequent real-world solution is for the person to get an antenna larger than they’d like to have a performance similar to their requirements. Or, due to budget, they get an antenna smaller than they’d like that doesn’t hit the lowest frequencies.

This customer-request dilemma should be contrasted to the situation where the engineering team doesn't know the operating conditions, thus contributing to the failure of the product in the field. For example, in one case, already-hot operating temperatures plus the Arabian Desert in the summer added up to temperatures darn near solder-reflow temperatures. FPGA components started to detach from the motherboard, leading to failure.

A log periodic antenna can only receive certain frequencies based on element length ... no amount of money will change the laws of physics involved.

A log periodic antenna can only receive certain frequencies based on element length ... no amount of money will change the laws of physics involved.

Human Errors and Ignorance

We get more exotic requests from people who don’t understand physics at all. One man wanted assistance designing a solar energy collector that let light in but didn’t let energy out. The design engineer let him discuss his idea with the intent of finding out why he thought this was possible at all. When he said it was the same energy source aliens used to run their space ships, and NASA was keeping it secret, he was politely dismissed.

We’ve received repeated requests for designing energy-harvesting antennas. Yes, you can harness the energy from radio waves, Wi-Fi signals and so forth. However, unless you are sitting right underneath the local FM station’s tower, you can’t collect much energy. The wireless energy collected is partially lost in the conversion to electrical energy. Thus energy harvesting is possible via receiving antennas, but it isn’t an economical way to power another receiving device. This is the reason wireless power systems typically require you to put your device on the surface that is charging it; and the benefit of that is eliminating the wires and plugs, not efficiency. Solar arrays located in space that beam down energy to receiving antennas on Earth would be efficient in part because there’s relatively little loss sending energy down from space and because they could be huge in the first place.

One common engineering joke is that hardware engineers assume software can solve everything while software engineers assume hardware can solve everything. When it comes to software-defined radios, many engineers assume that one single, simple antenna can be matched up with the all-purpose software-defined radio. In short, if the SDR can process anything, there must be an antenna that can receive anything, too. In reality, you can have one antenna that receives all signals but none of them without heavy interference or an array of antennas that receive a frequency range well.

There are bizarre requests that turn out to be failures in translation. One German customer seemed to want something that was out of science fiction when in reality, it was someone trying to translate low “free space path loss” from German to English as a technical specification. Free space path loss had been translated by Google into "it's the road you are traveling along, they are not charging you to travel on the road but it is costing you to travel on the road." This story is a result of my time working with Kent Britain, WA5VJB, of Kent Electronics.

The team commonly gets requests to design a very specific type of antenna with tight tolerances and performance specifications, only to be rebuffed when told how much it will cost.

We occasionally get requests to design something to stop government mind control signals. Those are almost always on a Monday morning as if they've mulled it over all weekend and then call the first business day. My boss honestly replies, "I'd love to help you, but I don't know what frequency they use. Have you tried something to block the signals? What do you use?" Note: it isn't always tin foil.

You Didn’t Buy That

Client: “I received the product. Where is the data?”

Me: “We sent the data sheet.”

Client: “No, we want the CAD files.”

Me: “We promised data sheets and technical specifications. That was included with the product.”

Client: “We want the manufacturing data and PCB files.”

Me: “We don’t sell how to make your products, we only sell the products. If you want custom design services including manufacturing data, you’ll have to pay for that—not buy an antenna.”

Laws Are Laws in Physics

Just because you can dream it up doesn’t mean you can achieve it, especially when the laws of physics are involved. With a good engineer, a real-world compromise in design can be achieved—if you have a sufficient budget.

This article is accurate and true to the best of the author’s knowledge. Content is for informational or entertainment purposes only and does not substitute for personal counsel or professional advice in business, financial, legal, or technical matters.

© 2017 Tamara Wilhite


Tamara Wilhite (author) from Fort Worth, Texas on February 28, 2017:

It is like someone saying I want something the size of a 2 gallon bucket but holds 5 gallons. You can have one or the other but not both.

Tamara Wilhite (author) from Fort Worth, Texas on February 28, 2017:

I've received requests to design antennas that cannot possibly be built, because the laws of physics determine how long the elements must be to receive a certain frequency.

Allie Backer on February 28, 2017:

Can u explain it to me better