Still waiting for an HD car radio converter

[Tom Wells]

I am ready to buy an HD converter, but will not consider ripping the factory radios out of my cars.

1. Such a converter should be in the antenna line,

2. Have proper trimming caps, in and out to preserve antenna tuning and sensitivity on AM,

3. Output RF analog stereo FM and analog AM modulated for the receiver to decode, on any chosen AM/FM frequency.

4. Have an audio output line, for use in vehicles with a line in.

5 It should have relay-switching to bypass all circuitry in the antenna line when off.

6. It should have the ability to blank the screen and/or turn off the backlight.

7. The best possible implementation would be an accurate slide rule dial, tuning knob, and a function knob for AM/FM/FM1/FM2.
With an analog meter, of course, so we can peak tune. ( this no. 7 is just kidding of course )


I have no use for any new step tuned radio for my car, and will not consider using such an AM radio unless it has variable bandwidth.
It does little good to manufacture converters useful to only a few late model makes.


Many car owners will not or can't replace original radios for a long list of reasons.

In the list of HD radio products this one is still missing, but the only one I'd have much interest in.

So, when is someone going to sell such a "universal" car HD converter?

 

[PhilJSmith67]

Why would you ever convert any HD Radio stream to anything in the AM band, except for maybe installing one of these converters in a '55 T-Bird with a stock tube-set radio? (good luck with that 6V electrical system!) The best AM section in any stock radio is never going to edge-out the FM section sound quality on the same receiver. Ever. I'm not talking about what the capabilities of AM vs. FM modulation are, I'm talking about the real world of car radios.

At least with FM, you could translate the HD Radio text to RDS. I believe there is an iPod modulator that does this now (puts artist/title on an RDS display).

 

[dumber than a box of hair]

http://www.diceelectronics.com/hd_integration.htm

Now available for some models of BMW, Mini Cooper, Toyota, Lexus, Scion, Buick, Cadillac, Chevrolet, GMC, Hummer, Pontiac, Honda and Acura. It plugs into the satellite radio input on the OEM head unit, will display the PAD data and will even include (for an extra cost) iPod integration as well.

 

[Tom Wells]

I have 4 old Plymouths and Dodges, the '65, '66, and '72 all with factory AM/FM radios where I have added line inputs, and
removed audio "shaping" capacitors which were added by the factory (bendix and motorola) because FM was only horizontally polarized in those days. They cut ALL the audio off with a .01 or some such right after the actual detector.
This was NOT in their AM designs at the time, and when I first got the FM for the '66, I wondered why the AM was so dull.
A quick check in Sams AR36 showed the offending cap. Out you go, and so with every other AM/FM factory radio since.
The idea then was to hide the FM hiss and make the FM as "mellow" as AM.
The Plum Crazy '65 Dart GT is my daily driver, and the AM has equal frequency response to the FM.
Properly tuned a little to the side, to prevent the frequency distortion of any IF amp too narrow to pick up all the sidebands when center tuned. Yes, when center tuned, any AM radio not revealing all the high frequency info available suffers from frequency distortion, by definition. Lacking this, and if the sidebands are equal (and not ISB) side tuning to provide full fidelity is LESS distortion, until you begin to
tune past "carrier within passband", then it gets ugly.

The 1971 Dart 340 GT has a wonderful Blaupunkt Richmond with DNR-switchable, and the hottest AM I could find in 1982 still with amazing high-end.

I 'd like to be able to switch such a converter between any of these, or the 1966 Belvedere II convertible.
So, there are many people such as myself, with "older" vehicles.

They should be able to get a converter that doesn't require them to add a line in.
I'd rather have the RF modulated output as the connection is one less.
I should be able to choose decoding of either AM-HD or FM-HD to either AM or FM analog.
Some people don't HAVE FM radios in their old cars yet.
Don't leave them out. It's a HUGE market.

 

[JohnnyElectron]

I have an HD Radio CAR Converter - and it has a lot to be desired - close, but no cigar. It is the Directed Electronics unit.

GOOD: FM Selectivity is superb. FM Sensitivity is slightly above average, but still not enough for rimshot FM stations. Display is pretty decent. $199, but was $99 (after I got mine) on sale WITH install at ABC Warehouse in Detroit area. RDS is nice feature.

BAD: Horrible distortion on RCA outputs for the first 10 minutes of operation. FM transmitter is slightly off frequency when used with AM stations, so you get sibilance!! AM sensitivity isn't that good - or maybe it's just HD that isn't 'good enough' on the AM band at 40 miles? Heat - runs at 97 degrees during 70 abient (measured). Can't keep it on analog only for a station that keeps going in and out of HD lock - AND their timing is off a tad - what a pain. There is some weird noise reduction / AGC / bandwidth 'digital program' going on with this unit that cranks down the volume when there is interference, so HD will blow your speakers when it locks in - strange AGC type issue that should be looked into.

It COULD be a good option: Add analog-only switch, add analog AM stereo, add stereo indicators for analog FM and AM, add heatsink to tuner section, correct RCA audio distortion and off-frequency issue with HD-AM. Add 15 minute buffer like XM radios? Have a manual AM bandwidth setting to keep it wide when desired.

It is a viable option, but I don't know if I would buy it again - I wish it was more like the revised Sangean tuner.

 

[Tom Wells]

I have an HD Radio CAR Converter - and it has a lot to be desired - close, but no cigar. It is the Directed Electronics unit.

GOOD: FM Selectivity is superb. FM Sensitivity is slightly above average, but still not enough for rimshot FM stations. Display is pretty decent. $199, but was $99 (after I got mine) on sale WITH install at ABC Warehouse in Detroit area. RDS is nice feature.

BAD: Horrible distortion on RCA outputs for the first 10 minutes of operation. FM transmitter is slightly off frequency when used with AM stations, so you get sibilance!! AM sensitivity isn't that good - or maybe it's just HD that isn't 'good enough' on the AM band at 40 miles? Heat - runs at 97 degrees during 70 abient (measured). Can't keep it on analog only for a station that keeps going in and out of HD lock - AND their timing is off a tad - what a pain. There is some weird noise reduction / AGC / bandwidth 'digital program' going on with this unit that cranks down the volume when there is interference, so HD will blow your speakers when it locks in - strange AGC type issue that should be looked into.

It COULD be a good option: Add analog-only switch, add analog AM stereo, add stereo indicators for analog FM and AM, add heatsink to tuner section, correct RCA audio distortion and off-frequency issue with HD-AM. Add 15 minute buffer like XM radios? Have a manual AM bandwidth setting to keep it wide when desired.

It is a viable option, but I don't know if I would buy it again - I wish it was more like the revised Sangean tuner.

Trying to understand here, does it seem like the FM transmitted frequency is not exactly what you've selected,
or the AM conversion to FM seems mistuned on the AM analog detection?
Presumably AM HD detection is exactly what it is expected to be, right?
Does it have trouble decoding AM HD until the tuning problem goes away?
Finally, how is the "straight AM" reception on the radio when the converter is off?
Does it maintain feedline impedance properly for incoming AM signals so I can enjoy full sensitivity of
my existing radio, or does it shoot sensitivity in the foot?

Is it intended that this become the only-and-primary tuner once installed or designed to fully switch in a bypass when off?

Does it inject stray data noise into weak AM signals?

 

[JohnnyElectron]

(see replies with "-")

Tom wrote:
Trying to understand here, does it seem like the FM transmitted frequency is not exactly what you've selected,
or the AM conversion to FM seems mistuned on the AM analog detection?

- Yes it seems like the FM modulator isn't right on frequency - but it's noticeable only on the AM-HD news talk stations as sibilance.

Presumably AM HD detection is exactly what it is expected to be, right?

- Well, I expected HD-AM coverage to be a little 'longer-range' than what it is. In the COL, you're okay, but that's about it for AM-HD. Forget about DXing AM-HD at night - you might get their station ID, but rarely can you decode HD-AM audio.

Does it have trouble decoding AM HD until the tuning problem goes away?

- Same decoding across the board. I did find that the switching power supplies (cigarette lighter) supplied by cellphone chargers and XM sat rad will wipe-out HD-AM on even the locals!

Finally, how is the "straight AM" reception on the radio when the converter is off?

- You can hear the 'click' of the antenna relay when you switch the converter off. You must have the converter off if you wish to use your tuning on your indash radio again. In dash performance is the same with the converter off - disabled with it on for all practical purposes.

Does it maintain feedline impedance properly for incoming AM signals so I can enjoy full sensitivity of
my existing radio, or does it shoot sensitivity in the foot?

- I can still get WLS-AM in stereo AM at night in Ohio on my in-dash, so it hasn't reduced the sensitivity hardly at all.

Is it intended that this become the only-and-primary tuner once installed or designed to fully switch in a bypass when off?

- Nope -but you must switch it off to engage the antenna relay to revert to the indash.

Does it inject stray data noise into weak AM signals?

- The tuner is in a metal case, and far enough from my 'fender antenna' that it doesn't feed noise back in; however, my tableop HD-AM radios has a problem keeping the AM loop far enough away from the radio itself as it does induce noise.

- Contact me for any more questions.
73's
John