Radio Waves: September 1, 2023

Antenna Mania

I recently had a chance to try out a really cool looking — at least in the opinion of some — antenna for my truck. The brand itself doesn’t matter much as these are all similar in design: flexible rubber with some sort of spiral wire inside to, as the description says, optimize reception for both AM and FM bands.

Most modern cars and trucks have special antennas that barely stick out of the body, and rely on signal amplifiers to get good reception. And most do quite well, including the one on my son’s Chevy Cruze … that radio gets better reception than almost any car radio I’ve ever used. 

But my truck is a 1999 Silverado, with the old school antenna. The factory original sticking up 31 inches from the fender, it is optimized for FM frequencies but does quite well with AM too, including picking up the HD digital stream of KBRT (740 AM) from San Pedro. and occasionally getting the identification from KMZT (1260 AM) even though I can’t get the actual HD sound until I get closer. FM is similarly solid everywhere I drive.

But I couldn’t help wondering if the mini flex antenna — a “new generation” with a carbon-fiber base covering, built-in copper wire, and “optimized AM/FM reception by nearly 40%,” whatever that actually means — could live up to the hype and at least match or even beat my factory install.

Turns out, it couldn’t, and I realized that the 40% optimized reception means the reception is about 40% of what I used to receive with my original. 

Most people may not have noticed the difference in FM performance, but I have an HD radio head unit, and it likes a good clear signal. FM stations generally did come in well with little interference similar to the original, though a few stations were just missing, such as KFBG (100.7 FM) and KGB (101.5 FM), which usually come in decently due to the signal shooting straight up the coast from San Diego to San Pedro … at least on a clear day.

But the HDs were hit and miss, with more reception problems than ever. Even Go Country (105.1 FM) had trouble locking in the HD stream, and that is usually one of the most reliable where I like.

AM on the other hand, was an entirely disappointing experience. Static everywhere, even over flamethrower 50,000 watt powerhouse KFI (640 AM). KMZT could not even be heard, and mid-signal stations such as KLAC (570 AM), KABC (790 AM), and KHJ (930 AM) were essentially unlistenable.

To prove it wasn’t just weather or atmospheric conditions on the test day, I put my factory antenna back on and all the reception problems cleared up. Immediately.

I bring this up not to bash the manufacturer of the antenna I evaluated. Instead I want to highlight the fact that antenna design, including length and other aspects, is exceedingly important to good reception. AM likes an antenna as long as possible, FM seems to work well with — on a car at least — that 31 inches preciously mentioned. Something to do with wavelength as I recall — engineers, feel free to confirm or correct me.

Newer cars usually use special small antennas are just that: antennas designed to work with the car’s construction and electronics to optimize reception.

Home radios and stereos can suffer from the same issues, and reception there can often be improved for AM by rotating the radio or moving it away from other electronics to cancel out interference. For FM, if you can connect it to a house antenna just like most televisions used to be, you’ll hear stations from greater distances than ever before.

Of course all of this is moot if you listen via apps. But that’s another column …

Sound Science

Another new toy I recently evaluated is a special little box that turns my normal iPhone’s Car Play wired system into wireless. Not an amazing must-have, mind you, but really a nice thing if you do have it. When I start up the truck, the phone connects automatically and starts playing whatever I was listening to last.

Yesterday I was driving my dog Snoopy back from a check-up at the vet’s office, and Alt 98.7 FM came on. I really wasn’t paying attention, but it turned out it was playing through CarPlay via the iHeart app. How does it compare with the over-the-air signal?

I checked. While it does sound good on the app, over the air is vastly superior on a direct comparison. More open, more dynamic … just better.

This is not an indictment of apps, by the way. Some stations, including both over-the air simulcasts and internet-only stations sound absolutely phenomenal on apps. And Alt does sound fine. But the difference in quality was noticeable, and probably related to reducing bandwidth on the internet stream to allow more connections as well as cut streaming costs. Just a guess … again, engineers can feel free to confirm or correct me.

Where the apps excel, though, are areas of weak reception. As long as the internet signal is good, apps can work where AM and FM cannot. 

And while I am on the subject of Alt 98.7 … I mean this with love … The Foo Fighters and Maneskin both made more than one song each … just sayin’.

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