Silicon Labs new HD IC's

[rbrucecarter5]

http://radioworld.com/article/silicon-labs-introduces-new-automotive-tuner-ics/24888

http://www.silabs.com/products/audiovideo/automotive-tuners/Pages/Si4768-69.aspx

 

[JohnnyElectron]

Two questions: did they include CQUAM encoding, and will they make the Shortwave reception available on a deluxe automotive version? That would be 'da bomb' if it did include those features.

 

[KeithE4]

Two questions: did they include CQUAM encoding, and will they make the Shortwave reception available on a deluxe automotive version? That would be 'da bomb' if it did include those features.

The overview shows that it's an FM-only device, while the PDF data sheet says it's AM and FM. No CQUAM, though. I'm guessing that Silicon Labs will update the data sheets in the future. They are rather incomplete.

 

[JohnnyElectron]

I got ahold of Silicon Labs, and they claim that in addition to HD-AM & FM, it also has capabilities (if used) for NOAA Weather Radio, Longwave and Shortwave. They are checking on CQuam capabilities for me as the salesman didn't know for sure on that.

 

[Tom Wells]

While we're wishing, I wish it had capability to implement a physical tuned circuit (or circuits) to add
a high-Q physical component intended to make the antenna "seem" reasonant, particularly for the MW band.
Most auto radios with an untuned input just seem lackluster on AM.
The sensitivity difference heard when adjusting the antenna match trimmmer cap on a "real" car radio
sure makes me long for one when I am stuck driving a vehicle that is deaf to AM MW.

 

[badjef]

They are checking on CQuam capabilities for me as the salesman didn't know for sure on that.

That means, "No".

Jeff in Sa-ra-so-ta!

 

[hubcity]

They are checking on CQuam capabilities for me as the salesman didn't know for sure on that.

That means, "No".

Two responses:

1.) Heh!

2.) You're absolutely right.

 

[Play Freebird]

While we're wishing, I wish it had capability to implement a physical tuned circuit (or circuits) to add
a high-Q physical component intended to make the antenna "seem" reasonant, particularly for the MW band.
Most auto radios with an untuned input just seem lackluster on AM.
The sensitivity difference heard when adjusting the antenna match trimmmer cap on a "real" car radio
sure makes me long for one when I am stuck driving a vehicle that is deaf to AM MW.

Another way to deal with this problem might be a high-impedance FET buffer/preamp that makes the short whip behave as a "voltage probe". My VW Jetta (with factory antenna mounted at the rear of the roof) apparently uses this approach and has the hottest AM sensitivity of any car I've owned -- so high that I hear static noise from the tires on some road surfaces. FM sensitivity seems on par with a quarter-wave whip, even though the antenna length is only 18 inches.

Of course, the drawback is a reduction in front-end overload immunity (and noise when I key the ham rig at full power), but it's not as bad as I expected.

This looks like an interesting short antenna project, has anyone here built one? I would like to try this out over the winter:

http://www.amrad.org/projects/lf/actant/

 

[tomservo]

Another way to deal with this problem might be a high-impedance FET buffer/preamp that makes the short whip behave as a "voltage probe". My VW Jetta (with factory antenna mounted at the rear of the roof) apparently uses this approach and has the hottest AM sensitivity of any car I've owned -- so high that I hear static noise from the tires on some road surfaces. FM sensitivity seems on par with a quarter-wave whip, even though the antenna length is only 18 inches.

Of course, the drawback is a reduction in front-end overload immunity (and noise when I key the ham rig at full power), but it's not as bad as I expected.

I've got the same style antenna on my Golf and can affirm the qualities you've mentioned.

Unfortunately the amplifier is in the base of the antenna and is subject to corrosion at the point where the antenna anchors to the car body. Mine's so bad the amp no longer works properly if it's below 55 or above 75°, and the make/loss/make/loss of the connection ruins AM reception when it does work.

Because I listen to the radio so infrequently now, and live within eyesight of pretty much the entire market's full power FMs, and literally under my town's only AM station, I have never bothered to fix it.

 

[badjef]

Another way to deal with this problem might be a high-impedance FET buffer/preamp that makes the short whip behave as a "voltage probe". My VW Jetta (with factory antenna mounted at the rear of the roof) apparently uses this approach and has the hottest AM sensitivity of any car I've owned -- so high that I hear static noise from the tires on some road surfaces. FM sensitivity seems on par with a quarter-wave whip, even though the antenna length is only 18 inches.

Of course, the drawback is a reduction in front-end overload immunity (and noise when I key the ham rig at full power), but it's not as bad as I expected.

I've got the same style antenna on my Golf and can affirm the qualities you've mentioned.

Unfortunately the amplifier is in the base of the antenna and is subject to corrosion at the point where the antenna anchors to the car body. Mine's so bad the amp no longer works properly if it's below 55 or above 75°, and the make/loss/make/loss of the connection ruins AM reception when it does work.

Because I listen to the radio so infrequently now, and live within eyesight of pretty much the entire market's full power FMs, and literally under my town's only AM station, I have never bothered to fix it.

If it is the same antenna, the Van Hool motor coaches had them also. The antennas would get broken by the low hanging tree branches. I took copper rods and used them in place of the original antenna and saved the company a boatload in replacements. It was a Bosch amplified antenna.

Jeff in Sa-ra-so-ta!

 

[pianoplayer88key]

While we're wishing, I wish it had capability to implement a physical tuned circuit (or circuits) to add
a high-Q physical component intended to make the antenna "seem" reasonant, particularly for the MW band.
Most auto radios with an untuned input just seem lackluster on AM.
The sensitivity difference heard when adjusting the antenna match trimmmer cap on a "real" car radio
sure makes me long for one when I am stuck driving a vehicle that is deaf to AM MW.

Another way to deal with this problem might be a high-impedance FET buffer/preamp that makes the short whip behave as a "voltage probe".  My VW Jetta (with factory antenna mounted at the rear of the roof) apparently uses this approach and has the hottest AM sensitivity of any car I've owned -- so high that I hear static noise from the tires on some road surfaces.  FM sensitivity seems on par with a quarter-wave whip, even though the antenna length is only 18 inches.

Of course, the drawback is a reduction in front-end overload immunity (and noise when I key the ham rig at full power), but it's not as bad as I expected. 

That definitely could be a major drawback, I'm sure.  I've sometimes wanted to listen to an AM station 400-500 miles away in the daytime (I've heard one from 626 miles away - 700 KALL North Salt Lake City received east of San Diego, CA), while within 1/8th mile or so of a 50kW first-adjacent (±10 kHz) non-IBOC station on the same azimuth.  (A possible example of the difference in signal strengths might be a 10-30 µV/m signal from the desired station, and a 30-100 V/m signal from the undesired station 10 kHz away; also using SSB may not be an option because of a 3-10 mV/m signal 10 kHz on the other side of the desired signal, not to mention I'd also like full C-Quam NRSC audio from the desired signal, without any blocking/splatter from the adjacents.) Would what you describe be sufficient for that, or would I need a better tuned circuit or something?  I wonder if there's something that would work with (and fit inside) either of my Tecsun (Si4734-based) radios (PL-380 and PL-606) to allow that?

 

[rbrucecarter5]

That definitely could be a major drawback, I'm sure. I've sometimes wanted to listen to an AM station 400-500 miles away in the daytime (I've heard one from 626 miles away - 700 KALL North Salt Lake City received east of San Diego, CA), while within 1/8th mile or so of a 50kW first-adjacent (±10 kHz) non-IBOC station on the same azimuth. (A possible example of the difference in signal strengths might be a 10-30 µV/m signal from the desired station, and a 30-100 V/m signal from the undesired station 10 kHz away; also using SSB may not be an option because of a 3-10 mV/m signal 10 kHz on the other side of the desired signal, not to mention I'd also like full C-Quam NRSC audio from the desired signal, without any blocking/splatter from the adjacents.) Would what you describe be sufficient for that, or would I need a better tuned circuit or something? I wonder if there's something that would work with (and fit inside) either of my Tecsun (Si4734-based) radios (PL-380 and PL-606) to allow that?

600 miles in the daytime was pretty easy with an old Delco from the 60's with a 60 inch whip. I would regularly listen to WNOE 1060 New Orleans in Abilene, TX.

GE Superadio 2's and (1)'s can do 600 mile daytime reception. I've got it on some Mexican stations like 640 from Houston. I suspect I am getting close to 1000 on 540 from Florida, but have yet to snag an ID I can positively copy. More exciting still is a possible daytime copy of KFI about 1400 miles away. There is definitely English language talk under the Mexican station that is NOT WWLS from OKC. Put a 5 foot box loop antenna on the radio and the band comes alive with 1000 mile plus reception during the day, but daytime reception of this sort is subject to extremely deep fades - so a station can be there and completely gone ten minutes later. More reliable is 700 to 800 mile daytime on the xtended band, I've had 800 mile plus reception for over an hour. But large loops like that are cumbersome to be sure, and definitely not mobile.

I've heard that some hams bottom load an AM whip to add more electrical length and do some incredible daytime AM reception in the high hundreds of miles.