Since we are on the topic of FM

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Brett Buck

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Since we are on the topic of FM
« on: 28 Nov 2009, 12:26 am »
    Apropos of the tuner thread, I ordered one of the little Sony tuners and am awaiting delivery. But, I figured it needs an antenna, so I got out my jumbo collection of antennas and started trying them again. When I came to this one:

http://www.amazon.com/gp/product/B000F477AC/ref=cm_cr_mts_prod_img

    I was very surprised to find that not only did it seem to get decent signal strength, it also almost completely eliminated my multipath problems with all the tuners I have. I just mounted it out the window temporarily, mostly blocked by the walls of the building, but with a clear shot at the KCSM antenna. To my tremendous surprise, it actually works perfectly with any of my tuners, even the FM-3 that, while a audiophile delight on a clean signal, is hardly the most selective or multipath-rejecting thing in the world. No background hiss, no (or at least not too much) sibilance, perfectly acceptable. This is the *only* antenna that has ever worked for me, and that's after a whole lot of experimenting.

     Brett

p.s. And, aside from the "burning dust" smell, after sitting untouched in my closet for ~2 years, my FM-3 has been running for about 8 hours no with no issues and not even the tiniest bit of drift - it was even still tuned correctly from the last time, didn't budge. And perfect dial tracking to the extent I can tell. Not too shabby, those guys had a pretty good idea what they were doing and the alignment procedure in the plans must be pretty good, too.

WGH

Re: Since we are on the topic of FM
« Reply #1 on: 28 Nov 2009, 01:00 am »
I know how you feel, receiving noise free FM is a real joy. I have struggled for years and have found a more directional antenna works better in my urban location. The Sony XDR-F1HD with it's terrific front end also helps to eliminate all the noise too.

I tried the FM Stereo 1/2 wave dipole outdoor antenna and it did not work at either my house or my shop. The tall buildings, 3-phase power lines, and construction cranes a few blocks away probably has something to do with my reception. The antennas that work for me are the Winegard HD6000 PROSTAR 1000 FM Antenna from Solid Signal. I also have a Antennacraft FM6 6 Element FM Antenna, also from Solid Signal, waiting in the wings for when KXCI gets their low powered digital transmitter repaired.

Wayne
 

avahifi

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Re: Since we are on the topic of FM
« Reply #2 on: 28 Nov 2009, 01:42 pm »
Does anyone have information about the audio output circuits in the Sony tuner?  I have not had time to take mine apart yet.

Regards.

Frank Van Alstine

Charles Calkins

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Re: Since we are on the topic of FM
« Reply #3 on: 28 Nov 2009, 03:47 pm »
I gave up on tuners and antennas. Now I listen to FM radio stations that are available through Squeeze box server. All kinds of different generes are available from all over the world. Haven't tried all of them but the ones I do listen to come in loud and clear. Much better than a tuner and antenna.


                                                     Cheers
                                                       Charlie

gerald porzio

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Re: Since we are on the topic of FM
« Reply #4 on: 28 Nov 2009, 05:23 pm »
Much better than a tuner and antenna.

In your location. Let's not generalize.

Brett Buck

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Re: Since we are on the topic of FM
« Reply #5 on: 29 Nov 2009, 01:44 am »
Does anyone have information about the audio output circuits in the Sony tuner?  I have not had time to take mine apart yet.

Here's some detail, maybe enough to figure out where to cut into the circuit and replace it with something else, were someone inclined:

http://www.ham-radio.com/k6sti/xdr-f1hd.htm

   Brett

oneinthepipe

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Re: Since we are on the topic of FM
« Reply #6 on: 29 Nov 2009, 02:50 am »
Does anyone have information about the audio output circuits in the Sony tuner?  I have not had time to take mine apart yet.  Regards.  Frank Van Alstine
 

Frank: 

There is some discussion on avsforum.   http://www.avsforum.com/avs-vb/showthread.php?p=16948329   


Quote from: narkspud;16837943
Throw in forced analog, and optical out, and I'm sold.
 

Quote from: m. zillch;16838057
Yes, forced analog, I forgot that one too.  Optical out is nice only in that optical digital transmission isn't susceptible to extraneous hum and noise from EMI and RFI fields, however I think we have an example here with compressed digital HD Radio that's analogous to Sony's minidisc format (digitally compressed and not CD equiv.). Since the signal never was PCM stereo 44.1k/16 bit in the first place, the few units on the market that do have a digital out (Sangean?) are really just taking the analog decoded signal and internally re-digitizing it for you through an extra stage of A to D which you later have to convert back through D to A in your stereo system. That's two extra unnecessary stages of conversion that potentially can degrade the S/N ratio a few dB, for example.  Yes I'm aware that only higher end units have digital out but my contention is that it is for marketability  and not better sound quality. The signal is not being kept in the digital domain the whole length to your stereo as would be with a CD player's digital out.
 

Quote from: narkspud;16845431

(1) With the analog outputs, you're at the mercy of whatever god-awful DACs they've put in your HD Radio. 

(2) PCM is lossless. As long as you maintain the sample rate and bit depth, there's no quality change whatsoever in converting from a PCM-based lossy codec to PCM itself. 

(3) The analog trip from the radio to the receiver is fraught with peril. It's generally better to stay digital as long as you can. 

(4) Once the analog gets to your receiver, if you're using Audyssey or some other such room EQ program, it's just going to convert it back to digital anyway, thus giving you two unnecessary conversions that DO cause significant quality loss. 

(5) SPDIF isn't a codec. It's an interface.
 

Quote from: m. zillch;16848273
Originally Posted by narkspud   

(1) With the analog outputs, you're at the mercy of whatever god-awful DACs they've put in your HD Radio. 

Well it gets rave reviews.

(2) PCM is lossless. As long as you maintain the sample rate and bit depth, there's no quality change whatsoever in converting from a PCM-based lossy codec to PCM itself. 

So converting from one codec to another is lossless no matter how many times you do it, D to D is always perfect. Nope, not buying it. Nor do I beleive the signal is kept in the digital domain as you claim. 

(3) The analog trip from the radio to the receiver is fraught with peril. 

Stop scaring the electrons! I give them adequate shielding and they do just fine where I live. 

It's generally better to stay digital as long as you can.  Even better would be if HDC was transmitted to the receiver itself, not that I know of any that can decode it, though. 

I'd need to see a circuit diagram to believe that the Sangean HD Radio keeps the signal in the digital domain entirely as you all claim before spitting out its digital out. As I said earlier I suspect it takes the decoded HDC signal, analog, and just re-digitizes it for you with a "whatever god-awful" A to D.


(4) Once the analog gets to your receiver, if you're using Audyssey or some other such room EQ program, it's just going to convert it back to digital anyway, thus giving you two unnecessary conversions that DO cause significant quality loss.  I the only one left that listens to stereo in "pure direct" analog stereo? Yes, only one stage of D to A, done, then only amplification and only two speakers (or headphones). 

(5) SPDIF isn't a codec. It's an interface. 

SPIDIF is a digital audio Format, hence the "F" (and can be used to describe a digital audio transmission line) and PCM is indeed a "codec". [read page 2] 
 

Quote from: m. zillch;16851268
Cost.   

People want digital outs on their portable MP3 players and iPod docks too, which are analogous compressed audio products that (for the most part) nobody stores music on in 44.1/16 bit PCM form, so what's the cheapest way to do this? Re-digitize the analog decoded MP3 sound with a dirt cheap A to D, and bingo, the public gets their "better sounding" digital out. I wish it weren't this way, of course. 

The same thing happened on Laser Disk machines regarding video outs. The public clamored to have the newer and better S-video jacks instead of the low life composite video RCA jacks. Thing is, the signal on the LD itself is a composite signal where the luminance and chromanance are combined from the get go so there's no way  to access them separately which is what makes s-video better with much less dot crawl and moire patterns. If the two are combined anywhere along the line the benefits of keeping them separate, as they are on S-VHS tapes, is lost. Manufactures solution? Put in a cheap comb filter which splits the luminance from the chromanance and give the customers their s-video jack. Hardly any customers were privy to the fact that for the best possible image the composite signal should be used, not the s-video jack, with a high quality external 3D digital comb filter instead.
   

hifigeezer

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Re: Since we are on the topic of FM
« Reply #7 on: 27 Jul 2012, 05:02 pm »
That Sony is out of production now.  I picked up a Sangean HD tuner because I have problems on many conventional tuners with IBOC noise caused by HD interference.  The Sangean was very quiet but did not image as well as conventional tuners.  I also tried the digital output of the Sangean into the DAC of my Logitech Transporter, which I think is pretty good.  The sound was the same, I think the limited bit rate is the problem.  I would like to have HD radio in my car but it causes many problems for high-fidelity listening at home.  I wouldn't buy any conventional tuner without researching first whether it will have IBOC problems.

lakeallen

Re: Since we are on the topic of FM
« Reply #8 on: 27 Jul 2012, 06:44 pm »
Hifigeezer,
I have the Sangean and found improvement running it to my Moon 100D DAC and upconverting the signal. It does improve the overall sound running it through the upconveting DAC.

pansixt

Re: Since we are on the topic of FM
« Reply #9 on: 27 Jul 2012, 07:32 pm »
I gave up on tuners and antennas. Now I listen to FM radio stations that are available through Squeeze box server. All kinds of different generes are available from all over the world. Haven't tried all of them but the ones I do listen to come in loud and clear. Much better than a tuner and antenna.


                                                     Cheers
                                                       Charlie

Charlie,
A couple of weeks ago I was preparing to listen to the special on Doc Watson on my local PBS FM station when I experienced an antenna glitch.

I stressed for a few minutes until I realized my Squeezebox has the Local tab on Net Radio and there was my station. It sounded great, but usually so does my Mac tuner.

James

Damn, I'm such a Slack Brain. I just saw the date on Charlies post. Oh well. Charlie I know you're still out there.

hifigeezer

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Have IBOC noise on your FM? Please do this
« Reply #10 on: 21 Aug 2012, 09:52 pm »

The FCC has established an "Interference Protection and Complaint Remediation" procedure to protect the reception of analog FM signals. It is documented starting at page 10 in http://hraunfoss.fcc.gov/edocs_public/attachmatch/DA-10-208A1.pdf .  This procedure is a bit complex, and it requires that you first contact the station that you believe is receiving the interference. The onus is on them to first try to work it out with the station supposedly creating the interference.