Small plastic roof mounted car antennas: why?

[upstate29651]

I may be a purist, but I DESPISE the "euro-styled" stubby plastic roof mounted antennas found on most new cars these days (either than or the "upscale" looking "sharkfin" design). What happened to a standard metal (encased in a plastic sheath) "whip" antenna, or even the rear window mounted ones? These new antennas do not hold up well at all to normal driving conditions, getting bent & twisted in a short period of time.

So which of all of these kinds of antennas do the best job at locking in & securing a signal? I can't help but think the old school whip would work best, but I want to hear your thoughts!

G

 

[ddsparxx]

Satellite radio antennas? I've seen such antennas on Chevy Silverado pickups and wondered if they were used for FM.

 

[pianoplayer88key]

All I ask of the antenna+radio on my next car (which'll be my first btw - mid 90s to mid 2000s Honda Civic is one make/model/age that I'm considering) is to be able to get armchair copy on a 2 µV/m AM signal in the middle of the day with a 20 V/m signal 10 kHz away, without any splatter or desense and with better audio than the analog on an HD signal.   Also, an Si475x-style signal strength meter would be nice (even though that means I'd have to get an aftermarket radio). As for why I'm wanting a sensitivity of < 2 µV/m, I'd rather have 2 or more stations fighting for the same frequency at noon in summer, than find a blank spot on the dial. I would also want similar performance on FM - KVYB-103.3 Santa Barbara, CA isn't the only FM station over 200 miles away that I want to be able to listen to. KZPO-103.3 Lindsay, CA (266 miles, 280 watts, 800m HAAT, 1756m ASL), also comes to mind, but I guess I'll just have to stream that one. Alternately, is there any AM station with a comparable format to KZPO whose frequency isn't occupied closer to San Diego, CA?

 

[KeithE4]

All I ask of the antenna+radio on my next car (which'll be my first btw - mid 90s to mid 2000s Honda Civic is one make/model/age that I'm considering) is to be able to get armchair copy on a 2 µV/m AM signal in the middle of the day with a 20 V/m signal 10 kHz away, without any splatter or desense and with better audio than the analog on an HD signal. Also, an Si475x-style signal strength meter would be nice (even though that means I'd have to get an aftermarket radio).

I think I'd be more concerned about the engine & transmission, especially on a car that old. ;D

 

[radioman148]

There was nothing better than the old whip antennas on the cars from the 60s thru the 80s if you were an AM DXer.

 

[rfry]

All I ask of the antenna+radio on my next car (which'll be my first btw ...)

Just curious as to how your next car can also be your first?

As for an AM band analog sensitivity of "2 µV/m" for that car radio+antenna -- where could you drive that car where the ambient r-f noise in the AM broadcast band would not be considerably higher than 2 µV/m?

Are you equating a receiver with an input sensitivity rating of 2 µV* as able to produce "armchair copy" if the arriving field intensity is 2 µV/m?

Note that actual r-f input voltage delivered to a receiver depends on much more than the arriving field intensity.

* receivers are rated for the conducted r-f voltage appearing across their antenna input terminals (measured in volts), not the arriving, radiated field intensity (measured in volts/meter).

 

[pianoplayer88key]

Keith, I plan to pay cash (not take out a loan) for the car, and best-case scenario dictates I only would have a few thousand bucks available with which to buy the car.

Rich, maybe I was a little ambitious when I mentioned the 2 µV/m figure. I do realize that in urban environments my sensitivity will be limited by noise. BTW I haven't measured with a field strength meter, but I'm guessing that the noise level in L.A. metro area is about 10 mV/m - based on David Eduardo saying that most people there won't listen to signals weaker than that. I'm not in L.A. so I don't expect the noise level to be that high. In rural areas east of where I am, I've heard several stations on portable radios from twice as far as Radio-Locator's 150 µV/m signal during the day, including KALL-700 North Salt Lake City, UT. Yesterday I drew a path from them to me on the enlarged M3 map (which I pasted together). I tried using the chart to calculate their field strength, but ran out of chart near the end of the 8 mS/m portion of the path just before I got to the Coachella Valley.
In the absense of excessive noise, I still would rather have multiple stations fighting for the same frequency than have blank channels. Maybe I wouldn't require 2 µV/m sensitivity to do that. I've read in an online PDF that co-channel protections are such that when a class A station is involved, another station's 5 µV/m contour cannot overlap the A's 100 µV/m contour. Also I came across another article that has a chart showing the atmospheric noise around 1 MHz being around 1 or 2 "Fa(dB)", exceeded 99.5% of the time - would that be dBµ? In any case, I'd want the radio and antenna (especially if I replace whatever comes with the car) to be sensitive enough to take advantage of times and places when the noise level is very low.

 

[spunker88]

I was skeptical of those smaller sized antennas at first, but they seem to do just fine in the few Toyotas I have tested. The right length of metal is there, its just in a spiral spring like design covered in plastic. I always thought it was better to have the metal stretched out straight, like in traditional antennas but they seem to do alright.

 

[Tom Wells]

For AM, there is no substitute for getting a real whip antenna up in the clear, AND good RF grounding
everywhere in the car. Modern PWM super pwr audio amps often throw a lot of rf right in the AM band,
so it may not be posssible in a modern audio car system to really turn up AM without really awful noises.

Any attempt to make antennas smaller than optimum is simply less capture area, and cannot help.

The amazing thing is that whip auto radio antennas work as well as they do on MW, being SO much smaller than reasonant.

I'd suggest leaving the factory radio in a modern car, and getting a mid-60s vintage auto radio..then
take the detector output straight to a line input on the new car sound system.
Yes it should have its own separate antenna. Make sure the AM radio has an antenna trimmer capacitor,
and adjust it on the upper end of the AM dial...and there will be no lacking of sensitivity in a '60's AM car radio.
And you will be able to TUNE it, instead of being stuck on 10khz steps.

 

[IT_Guru]

There was nothing better than the old whip antennas on the cars from the 60s thru the 80s if you were an AM DXer.

I used to think the same thing until I got my 2008 Honda Accord. The AM/FM antenna is in the back window with the XM antenna mounted on top of the car. My car before that was a 1994 Chevy Cavalier with the whip antenna mounted on the front right fender. To my surprise, the factory radio in the Accord out performs the Delco AM Stereo/FM Stereo factory radio that was in the Cavalier. In NE Ohio halfway between Cleveland and Pittsburgh I can receive WLW from over 200 miles away during the day and in certain areas I can also receive WLS during the day. I only wish it had an AM Stereo receiver like my Cavalier did.

The worst antennas ever were in the 70's when GM mounted them in the windshield. I remember my dad had an Impala and it was a challenge to pick up the locals because of all the engine noise.

 

[upstate29651]

So what's the reasoning? Style? Cost? I can't believe it's that expensive to manufacture a whip vs. these tiny cheap plastic nubs.

G

 

[kilokat7]

I may be a purist, but I DESPISE the "euro-styled" stubby plastic roof mounted antennas found on most new cars these days

Are these really used for AM reception? Can someone with one of these vehicles confirm this? I always assumed (maybe mistakingly) that these were satellite radio antennas (for GM's OnStar network, Sirius, XM, etc.) and not for AM or FM reception.

 

[kenb]

Great topic... I wondered too. I drive a Buick Rendevous that has one of those crappy grid antennas in the front windshield on the passenger side of the car. At work, I drive a Ford Windstar van that has a crappy grid antenna on a rear side window (passenger side). In both cases, the AM reception is TERRIBLE. And, forget the FM reception too. As soon as I get away from the broadcast towers line of sight here in the valley, the stations fade out and all of the engine noise, turn signal noise, windshield wiper noise and etc. tend to dominiate with whistles and grinding sounds.
I thought about replacing the antenna on my Buick to an old style whip AM/FM standard antenna. Would it work, just plugging it into the back of the radio or is it not that simple (assuming I could get the cable to the back of the radio without dismantling the entire car)??? If it is possible to switch the antenna out, would it be best to leave it to a professional car radio installer or the Buick dealership? And finally, is it the fault of the original radio that came with the car with the wonderful in the steering wheel buttons for volume and changing stations and running the CD player-- would a new radio with using the existing in the windshield antenna be acceptable? The car is paid for, but I long for the reception of all the old standard car radios that I had in my previous cars going back to the 1960's. Comments?

 

[dave73]

The worst antennas ever were in the 70's when GM mounted them in the windshield. I remember my dad had an Impala and it was a challenge to pick up the locals because of all the engine noise.

GM was doing that around 1967 or 1968 with many of their cars. My parents had a 1971 Buick Wagon, 1972 Chevy Impala, & a 1973 Chevy Nova with the windshield antenna. For just my mom, a 1980 Chevy Malibu wagon, 1980 Oldsmobile Cutlass LS (eventually renamed Cutlass Supreme in 1983 or 1984), and another car I can't think of right now. They were ok, but they weren't as good for reception. GM discontinued those antennas around the 1984 model year, & went with the regular whip antenna (either on the front passenger fender, or on most late 80's model cars, the back around the trunk area). GM has since gone back to windshield antennas. My sister's 2000 Pontiac minivan has the updated windshield antenna. My Aunt Nancy's Cadillac (don't know the model) also has the same updated windshield antenna. Even my Aunt Dawn's 2000 Buick Park Avenue has the same updated windshield antenna.

 

[Darth_vader]

"The worst antennas ever were in the 70's when GM mounted them in the windshield. I remember my dad had an Impala and it was a challenge to pick up the locals because of all the engine noise."

I have one in my 87 Bronco, a copper-wire dipole embedded in the glass. Never had any problem with it, wired into my XDR-F1HD. Not even when I have it switched into Ibiquity mode driving about town! The long-after-market Kenwood radio I have in there is another story, but then, I really got that one for its CD/MP2 player and line inputs anyways. Its MW/FM tuners are crap to begin with, aerial notwithstanding.

The windshield itself was also an aftermarket job done by whomever owned the Bronco before I, since (as far as I know) Ford weren't putting those in their cars by that time, if ever.

 

[radioman148]

I had a 73 Buick. Worst antenna ever. It was in the window and reception was terrible.

 

[cyberdad]

I has an '82 Cutlass with a windshield mounted antenna that worked pretty well.  Not great, but nowhere near as bad as I expected.  Currently, I have a '99 Buick Le Sabre (with 257,000 miles). I bought it new and drove it all over the U.S. And Canada east of the Rockies as a company car.  Lots of long road trips.  Antenna is mounted in the rear window and the factory installed Delco radio is a "DX stud" on both AM and FM. Who knew? I certainly  never expected a great DX unit out of this.

This car's road trip days are long over, but it still runs great and the radio still works great.

Meanwhile, Mrs. Cyberdad has a Mercedes ML 350. Fancy (looking) factory radio, with the stubby plastic antenna. But as I've posted previously, the AM is terrible. Even the Bose audio is awful.  FM, however, is another story.  The radio/antenna grabs/holds FM signals with the best of 'em.  Good (if unremarkable) audio as well.  The unit also includes weather band, and does a fine job with that also.

 

[radioman148]

I has an '82 Cutlass with a windshield mounted antenna that worked pretty well. Not great, but nowhere near as bad as I expected. Currently, I have a '99 Buick Le Sabre (with 257,000 miles). I bought it new and drove it all over the U.S. And Canada east of the Rockies as a company car. Lots of long road trips. Antenna is mounted in the rear window and the factory installed Delco radio is a "DX stud" on both AM and FM. Who knew? I certainly never expected a great DX unit out of this.

This car's road trip days are long over, but it still runs great and the radio still works great.

Meanwhile, Mrs. Cyberdad has a Mercedes ML 350. Fancy (looking) factory radio, with the stubby plastic antenna. But as I've posted previously, the AM is terrible. Even the Bose audio is awful. FM, however, is another story. The radio/antenna grabs/holds FM signals with the best of 'em. Good (if unremarkable) audio as well. The unit also includes weather band, and does a fine job with that also.

Those factory installed delco radios on 60s GM cars were fabulous for AM DX. Especially if you had the ouside whip antenna from back then. They picked up everything.

 

[Signal]

I've got the standard factory radio with whip antenna in my 1999 Ford Ranger.

 

[pianoplayer88key]

I know of someone who, using a 2006 Ford Ranger's radio and whip antenna, heard 8.5kW 650 KGAB from Orchard Valley, WY (near Cheyenne) until he crossed the Mississippi River in St. Louis, 792 miles away. Also, using the same radio, he heard 50kW 640 KFI Los Angeles to just east of Willcox, AZ (50 miles W of the AZ/NM border, 506 miles from KFI) and 50kW 700 KALL North Salt Lake City, UT, into the western part of New Mexico, probably over 617 miles away. He also heard 250-watt non-dir 690 KWRP Pueblo, CO, 193 miles away about 40 miles into Kansas on I-70.

Would the car radios from the 1960s, for example, be much better at midday AM DX than that?
For example, using a portable radio and tuned loop antenna, I've been able to hear 50kW 680 KNBR San Francisco, CA (445 miles), and 50kW 700 KALL North Salt Lake City, UT (626 miles), at my house, in spite of being only 32 miles from 77 kW 690 XEWW Tijuana, Baja Calif Norte. With a reasonably selective and sensitive car radio and antenna, should I expect a better signal from KALL with less splatter from XEWW?