feedback.pdxradio.com » Politics and other things

I just acquired an XDR-F1HD today.....

(11 posts)
  • Started 3 years ago by motozak3
  • Latest reply from Alfredo_T

  1. motozak3

    vacuum tube
    Posts: 4,469

    This is truly a magical box.

    For the first time ever I am hearing KXXO and KPPK in full stereo, and with almost no static or multipath. They sound almost like local stations in this area, despite being between 40-70 miles away in either case. Earlier tonight I was hearing the Indians chanting on KTNN, out of Window Rock, AZ on 660, which, dear readers, my Grundig can't even pick up!

    That's primarily why I got this rig.

    The IBAC reception's there when I need it, I guess. Too bad I can't force it into analogue-only reception. (Is there some hack for this box like there reportedly is on the Sangean?)

    By and large, the XRD-F1HD is probably one of the best analogue rigs I have used.

    (Pocketradio beware!!)

    Posted on December 3, 2010 - 01:48 AM #
  2. skeptical

    vacuum tube
    Posts: 5,958

    I thought it was the new prosumer Canon 3-D videocamera. Imagine my disappointment that is was actually radio related.

    Posted on December 3, 2010 - 01:53 AM #
  3. Those HD Radio receivers are quite impressive on analog AM and FM in terms of sensitivity and selectivity. Actually got WGN 720 on the Accurian receiver along with making some of my best FM DX catches ever. Never heard KTNN 660 as of yet but I keep trying for it even though I don't have much success.

    Posted on December 3, 2010 - 02:10 AM #
  4. motozak3

    vacuum tube
    Posts: 4,469

    You should have tried an hour and a half ago, KTNN was blowing in nice and loud down here with the aid of my Selectatenna!

    Is KXXO even transmitting an IBAC signal? They didn't seem to be when I was in the area earlier this year, when observing on a slightly off-tuned analogue rig.

    Posted on December 3, 2010 - 02:26 AM #
  5. KXXO is not digital should know their transmitter is darned near in my backyard! 660 is kind of a problem here because of another station from Calgary that booms in rather than KTNN.

    Posted on December 3, 2010 - 02:55 AM #
  6. jr_tech

    vacuum tube
    Posts: 4,058

    Great! I have used one for several years for (mostly) FM DX ... my classic high end FM tuners with custom if filters don't get much use anymore!

    "Too bad I can't force it into analogue-only reception. (Is there some hack for this box like there reportedly is on the Sangean?)"

    See K6STI website:

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

    Posted on December 3, 2010 - 12:04 PM #
  7. RadioBuggie

    vacuum tube
    Posts: 4,507

    Yes:
    Pocketradio...BEWARE!!

    Posted on December 3, 2010 - 12:51 PM #
  8. Alfredo_T

    vacuum tube
    Posts: 5,240

    I was able to find a datasheet for the front-end IC used in this radio. It is a TEF6730, made by Philips/NXP. See http://tec.icbuy.com/upload/database/2007-08/0708080942520003895001186537372.pdf Scroll down to page 45 for an applications circuit, designed for an automotive application. It would not surprise me if the circuit inside the Sony looks a lot like this, with the exception of some changes in the antenna circuit to accommodate a loop antenna for AM.

    My observations from skimming the data sheet and reviewing the schematic are:

    • Using the application circuit and the noise reduction features of the companion SAF7730 DSP, the FM sensitivity is 1.1 uV (measured at the antenna). This is accomplished without the use of any external RF preamplifiers.
    • Using the application circuit and an audio bandwidth of 2.5 kHz, AM sesitivity is 50 uV (measured at the antenna) for a 26 dB signal-to-noise ratio.
    • The FM front-end is tuned by a single tank circuit, using external components (coils and varactor diodes).
    • The FM and weather-band mixers are image-reject types, which is why this design can get away with using only a single pre-selector stage.
    • The AM front-end is not tuned; instead a band-pass filter, using external components is used to bring in the entire band of interest. This design can get away with doing this because of the high IF frequency.
    • The IF output is 10.7 MHz, regardless of whether reception is AM, FM, or weather band.
    • The AM section is designed to handle longwave, mediumwave, and shortwave (up to 26.1 MHz).

    CAUTION: The 1.1 uV sensitivity figure is a "marketing number." That is, NXP doesn't say anything about the signal-to-noise ratio of the demodulated audio when the RF input level is so low.

    Posted on December 3, 2010 - 02:54 PM #
  9. jr_tech

    vacuum tube
    Posts: 4,058

    "CAUTION: The 1.1 uV sensitivity figure is a "marketing number." That is, NXP doesn't say anything about the signal-to-noise ratio of the demodulated audio when the RF input level is so low."

    K6STI reports measuring the XRD-F1HD at:

    50-dB quieting sensitivity, mono 13.5 dBf
    50-dB quieting sensitivity, stereo 13.5 dBf

    The specs on my Yamaha 950 are, for example:
    Usable sensitivity _____________ 9.3 dbf (o.8uv)
    50-dB quieting sensitivity, mono 15.1 dBf (1.55uv)
    50-dB quieting sensitivity, stereo 37.7 dBf (21 uv)

    The Sony performs very well for not having an RF stage!

    Posted on December 3, 2010 - 05:52 PM #
  10. motozak3

    vacuum tube
    Posts: 4,469

    Here is a block diagram of the 6730 chip as I believe it to be implemented in the sony box, http://ukradio.info/XDR-F1HD/TEF6730.jpg , from the page at http://ukradio.info/XDR-F1HD/ . Apparently this chip also covers Japanese FM and OIRT with a little bit of coaxing. Receiving SW on this thing sure would be nice. I imagine such usage would probably require significant changes to the receiver's firmware, if that's even possible. (I wonder if anyone's ever teird doing that.....)

    @jr_tech--

    Thanks for that above link. I might try that one of these days when I am feeling more confident in my abilities with a soldering iron. ;o)

    Edit add:
    I also found an interesting memory backup hack using a cell phone battery, http://ibit.com/HDRadio/ . Using a suitable 12VDC-120 VAC inverter, suitable line/aerial connections and under-the-dashboard mounting hardware, I could see working an F1HD into a rather nice add-on to a car stereo (assuming the stereo possesses an RCA-plug auxilliary input, like the Kenwood I have in the Bronco.)

    Posted on December 3, 2010 - 08:21 PM #
  11. Alfredo_T

    vacuum tube
    Posts: 5,240

    It appears that you can have DigiKey order one of the "flavors" of the SAF7730 DSP chip for you (cost is about $22.00), but they don't provide any documentation for it! This seems pretty peculiar to me! I am really curious how the writers of the ham-radio.com review for this radio knew about the different FM IF filters that are implemented in the DSP, given that the documentation appears to be hard to find, if not a trade secret.

    The front-end chip is controlled through a protocol called I2C. I2C signals are pretty easy to generate: there are two lines, a clock and the data. The clock typically runs in the range of 100 kHz to 400 kHz, although in practice, there is usually not a lower frequency limit. You use the clock to load different registers in the device, bit-by-bit. It would not be too difficult to program a PC's parallel port or a microcontroller to generate these waveforms (when I worked at Lattice, we had a program that used the parallel port to communicate with the I2C interface of one of our chips). Some modification or bypassing of the MW front-end filter would be required to receive shortwave or longwave. The narrow bandwidth of the AM IF would work well on shortwave. The only unfortunate thing is that the analog AM feature of this receiver module does not handle selective fading very well because it does not use a synchronous detector (according to the review at hamradio.com).

    Posted on December 6, 2010 - 12:43 PM #

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