HD-BLADE vs. Potato: Can a spud bring the goods?

Why pay for antennas when you can grow them? There’s an article at WikiHow that claims that a plain old potato can do just as well as a commercially made antenna. We decided to test it against our HD-BLADE antenna to see if that’s true. If it is… we’re in trouble.

This is an ordinary potato bought from the grocery store. It cost under $1.00 and was left at room temperature for a day or so, mostly because it never got put in the refrigerator where maybe it should have gone.

We started with a length of Solid Signal RG6 cable and added CoaxMax connectors to the ends. After all the testing was done with the HD-Blade we stripped the end off and exposed a 3″ length of bare copper. The dielectric and braid were covered using electrical tape to avoid short circuits and the performance of the wire was tested by itself.

We then rather unceremoniously jammed the copper into the business end of the potato (although we’re not 100% sure it was the business end, it sounds good when you say it that way) and attached the cable with a little electrical tape like the WikiHow article. The potato/antenna was then tested three times and the results averaged.

Testing parameters

In theory, the parameters shouldn’t matter as long as they are consistent but we’ll publish them here so you know that we were trying to be as scientific as possible.

All testing was conducted at our West Coast Operations Center outside of Los Angeles, California. Testing was conducted indoors with both antennas vertical at a height of one meter from the floor and pointing exactly toward Mt. Wilson where most LA area broadcast signals originate.

The test instrument was a Solid Signal DIGIAIR-PRO ATSC meter set to measure digital signals. With a 75 ohm terminator, the instrument measured 31.3dBμV (displayed on the instrument as dBuV) corresponding to -77.45dBm. This represents its lowest observable signal level.

The cable used for testing was a Solid Signal custom 3 foot RG6 cable with solid copper center conductor. It had previously been tested for continuity and signal and is believed to be representative of a typical well-made cable. The same cable was used for all testing.

The TV used for ATSC channel scans was the Insignia NS19E310A13.

The antennas tested were:

HD-BLADE Antenna from Solid Signal
Potato/antenna

All testing took place during the same one-hour interval with sunny skies and no noticeable obstructions, at a distance of roughly 90km from Mt. Wilson, at an elevation of approximately 450m above sea level.

ATSC Channel scans

All three antennas were placed in the same position and a regular ATSC channel scan was run. Only digital channels were scanned. Channel number totals include subchannels.

HD-BLADE: 68 Digital Channels

Bare Wire: 9 Digital Channels

Potato: 47 Digital Channels

It’s obvious that the bare wire doesn’t do a whole lot, but the performance of the potato was fairly surprising. It didn’t hold up to our HD-BLADE but there’s no doubt that the little tuber was pulling its weight and frankly it performed better than the Clear TV antenna we tested. The next step was the signal meter to see how the potato did in scientific testing.

Signal Meter test results

All observed measurements have been converted to dBm to correspond with TVFool.com’s benchmark readings for those frequencies. With the exception of the bare wire measurements, any frequency measurements that were close to the meter’s lowest observable level of -78.5dBm were discarded.

The data showed that in some frequencies, the potato performed surprisingly similarly to the HD-BLADE, while other channels saw performance roughly between that of bare wire and that of the HD-BLADE. Bare wire performed uniformly poorly, with any differences in signal most likely due to the testing environment.

Frequency (MHz) Bare Wire HD-BLADE Potato
177 -75.05 -70.15 -69.75
183 -75.05 -72.15 -74.55
189 -75.35 -65.15 -65.45
213 -76.25 -66.85 -70.15
533 -77.55 -67.35 -75.45
557 -77.35 -68.75 -70.25
563 -76.95 -68.25 -68.15
575 -77.45 -63.25 -64.15
581 -77.95 -63.55 -67.15
587 -78.25 -63.25 -72.45
593 -78.25 -72.25 -75.85
599 -78.05 -61.95 -71.85
605 -78.25 -57.85 -68.65
623 -78.05 -65.55 -68.35
641 -76.85 -71.95 -69.45
647 -76.85 -69.15 -73.05
671 -77.65 -71.75 -76.55
677 -77.25 -65.35 -69.75
683 -77.45 -71.55 -73.15

 

Conclusion

It’s not likely that you would want to use a potato as an antenna for very long. Aside from the obvious issues with mold and decay, it’s likely that its performance would degrade as the moisture content of the potato went down, eventually leading to the potato providing no benefit. However, we were quite frankly shocked by how well it performed in the short run. The relatively high acidity and moisture content of a potato makes it a good conductor of electricity and the skin seems to provide no barrier to RF transmissions.

In seriousness, though, a potato is a poor substitute for an antenna. During our tests, the cable kept falling out and there were several cases where we threw out test results where we saw extremely poor performance, even lower than bare wire. There are several hypotheses for this. It’s possible that air began to surround the center conductor and didn’t allow it to make full contact with the potato, and it’s equally possible that the electrical tape that was covering the braid and foil was not enough to insulate completely from short circuits. That said, it makes for an interesting demonstration in the short term and who knows… a little spud might hold you over while you’re waiting for the real antenna to arrive.

Advantage: Solid Signal

 

About the Author

Stuart Sweet
Stuart Sweet is the editor-in-chief of The Solid Signal Blog and a "master plumber" at Signal Group, LLC. He is the author of over 10,000 articles and longform tutorials including many posted here. Reach him by clicking on "Contact the Editor" at the bottom of this page.