A funny/cautionary tale (I hope) about an HD radio :)
mhardy6647
Posts: 33,909
in Electronics
I hope that this little story strikes some folks here as amusing -- I was amused, when all was said & done. I further hope that the very kind individual who enabled it won't mind my posting it! I share it mostly to illustrate my own audiophile foibles (as @SeleniumFalcon might put it).
Preface
We live in the deep boondocks for FM reception in general, although we're fortunate to have a good station (one of the VT public radio transmitters) not too far away and way up on top of a nearby mountian (Ascutney), in Windsor, VT. The local transmitter is WVPR-FM, broadcasting on 89.5 MHz. VPR maintains both traditional analog FM stereo broadcast and a three-channel HD radio OTA broadcast using WVPR. The three HD (hybrid digital, not "high definition") channels are: VPR News (also the analog channel on 89.5), VPR Classical (local and canned classical programming 24/7, which is also analog broadcast OTA on other frequencies (some of which we can receive), and BBC News 24/7.
We also live in a house with a metal roof... and I have been too lazy to erect a proper antenna. Laziness, as you'll see, is a leitmotif in this little tale. Our reception of VPR's analog signal is generally good, but sometimes it -- umm -- defecates the bed (so to speak), requiring occasional fiddling with the antenna.
In September, 2017, VPR had an open house at their new HQ in Colchester, VT, and Mrs. H and I trundled up there to see the place and meet some of the VPR folks. While there, I chatted with the broadcast engineers about the challenges of reception in the interesting terrain in NH and VT. They said that they have had good success with HD radios in problem locations, and even had a little display of various kinds of radios set up (including a sample of the "legendary" Sony XDR-F1HD radio). I guess they used to keep some "in stock" and sell them (at their cost?) to folks who needed one -- but that ship had sailed by Sept., 2017. Nonetheless, I became somewhat obsessed by the urge to try an HD radio or tuner to see if it was any better at our house (i.e., with the same itty-bitty indoor antennae I'd been using).
more to come...
Preface
We live in the deep boondocks for FM reception in general, although we're fortunate to have a good station (one of the VT public radio transmitters) not too far away and way up on top of a nearby mountian (Ascutney), in Windsor, VT. The local transmitter is WVPR-FM, broadcasting on 89.5 MHz. VPR maintains both traditional analog FM stereo broadcast and a three-channel HD radio OTA broadcast using WVPR. The three HD (hybrid digital, not "high definition") channels are: VPR News (also the analog channel on 89.5), VPR Classical (local and canned classical programming 24/7, which is also analog broadcast OTA on other frequencies (some of which we can receive), and BBC News 24/7.
We also live in a house with a metal roof... and I have been too lazy to erect a proper antenna. Laziness, as you'll see, is a leitmotif in this little tale. Our reception of VPR's analog signal is generally good, but sometimes it -- umm -- defecates the bed (so to speak), requiring occasional fiddling with the antenna.
In September, 2017, VPR had an open house at their new HQ in Colchester, VT, and Mrs. H and I trundled up there to see the place and meet some of the VPR folks. While there, I chatted with the broadcast engineers about the challenges of reception in the interesting terrain in NH and VT. They said that they have had good success with HD radios in problem locations, and even had a little display of various kinds of radios set up (including a sample of the "legendary" Sony XDR-F1HD radio). I guess they used to keep some "in stock" and sell them (at their cost?) to folks who needed one -- but that ship had sailed by Sept., 2017. Nonetheless, I became somewhat obsessed by the urge to try an HD radio or tuner to see if it was any better at our house (i.e., with the same itty-bitty indoor antennae I'd been using).
more to come...
Comments
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That Polk Audio HD radio mini system is super cool!
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I wish I would have bought 6 or 8 of those Sony XDR-F1HD's. I had a chance they cleared them out at BB for $77. Had I known.....
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I wish I would have bought 6 or 8 of those Sony XDR-F1HD's. I had a chance they cleared them out at BB for $77. Had I known.....
Ain't it the truth?That Polk Audio HD radio mini system is super cool!
Speaking of Polk products -- I espied a pair of these installed in the anteroom of one of their small "studio"/performance spaces.
I will get back to the story anon -- I do want to point out that there is a happy ending
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So... where was I? Oh, yes, Silver. Silver and gold...
Ooops, my mistake, that was Burl "Snowman" Ives, reflecting on Yukon Cornelius (or was it his brother, Don, the Soul Train guy?). But I digress...
In 2018, a nice fellow here at the Polk forums listed a Sangean HDT-1 HD Radio tuner for sale here on the forum. I fairly leapt at the chance to acquire one and give it a go (I am, if nothing else, a late adopter...), so I bought it. The seller shipped it promptly and well packed, and I was pleased to receive it. It was, as advertised, absolutely pristine. I excitedly unpacked it, hooked it up, and gave a quick listen. Seemed to work fine.
Then, I got distracted by something shiny or a squirrel or something and... time passed.
generic image of an HDT-1
PS I won't mention the seller's name, but it's a matter of public record here -- and I DO WANT to make it abundantly clear that he, and the transaction, were great. Absolutely no complaints about the transaction! I would be the problem... 
Mostly that laziness thing.
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Re: Sangean and HD Radio, I recently ordered one of these for my desk and I've been happy with it for the price: https://www.amazon.com/Sangean-HDR-16-Radio-FM-Stereo-Portable/dp/B01BY7YIOQ
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Weeks or months passed... at some point, I probably got frustrated with multipath listening to VPR on the big-boy hifi upstairs, so I got the Sangean HD tuner out and hooked it up properly. Fired it up, set the clock, tuned to 89.5 and selected HD channel 1. The signal came booming in, loud and clear and clean and quiet (in terms of background). I settled down to listen to... whatever it was. After a little while, though, the "HD" symbol would start to flash and the radio would drop back to standard (analog) FM. A little while longer, and the analog signal would start to flutter and fade and, eventually... nada.
Well, that's odd -- but 1) I don't know anything about HD FM (in a practical sense, that is) and 2) our environment is... interesting. Around this same time, we had added another 3-ish kW of solar panels to the house -- on the roof of the garage -- right over the tuner and its (still very much indoor) antenna. These were modern solar panels -- not those stone-aged ones from 2010 on the main part of the house -- with micro-inverters and WiFi monitoring of output and such. All kinds of digital kr@p, you know? And it was daytime. Maybe all that nonsense was bjorking the HD signal, or the operation of the tuner in general?
Unfortunately, these notions were all testable, and test I did, although none too time-efficiently. I tried listening at night, or in a different part of the house, or... well, you know, that kind of stuff. Not double-blind, though
When all was said and done, it seemed to have some sort of intermittent but time-dependent thing going on -- when cold, it worked perfectly, but give it a couple of minutes to "warm up", and it would, like an old soldier, just kinda fade away...
Well, that sounded to me like a component "breaking down" as it warmed up, and I KNOW how to troubleshoot & isolate such issues -- with a can of "circuit chiller" ("FreezeMist" was the trade name, at least back when my father was still doing TV repair for a living).
And another year, or so, passed...
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June 2021. A pandemic has come and (largely) gone. We finally donated 15 months' worth of treasures to our church's much delayed but usually semiannual rummage sale. I started organizing and cleaning up (my) junk in the basement during a week of hot weather (it is cool in the basement). I started fiddling around with the three pairs of KLH Six loudspeakers here (another story, for another time). Oh, and I reanimated a pair of roadside-find AR-4x speakers (did I mention that I am easily distracted) -- and, then again, there's (still) that Sangean HD tuner.
That Sangean HD tuner.
Mind you, something like 2-1/2 years had passed, and not only had I not tried troubleshooting it as described above, I hadn't even popped the top and looked inside. I mean, heck, maybe there's something loose inside -- it did get shipped, you know?
One June day, I popped the top.
I figured I'd look for anything broken or loose, or -- you know -- funny looking. Everything looked quite serious Nothing looked loose -- but looks can be deceiving.
I noticed several "wiring harnesses" with multi-connector terminations here and there. They were all a bit small and delicate looking, and I have short, fat fingers so I got myself a chopstick and gingerly but firmly pushed on them all to (re)seat them, in case they were... you know... loose.
Nothing seemed particularly loose, but hope springs eternal.
Not being an optimist I didn't even think about putting the cover back on it, but I MacGyvered up a short wire antenna and plugged it in (in the basement) and tuned to 89.5 MHz.
... and it worked.
... and it continued to work, for more than a few minutes.
Time for the acid test Again, without putting the top back on, I took it upstairs & hooked it up to an unused input on that dump-find Yamaha 5.1 HT receiver thingy up there.
... and it worked.
and it continued to work.
Gingerly, and without much confidence (I think I mentioned that I am not an optimist), I unplugged it (!) and put the top back on, and hooked it back up again and turned it on.
... and it worked.
and it continued to work.
and it still continues to work.
My best guess is that one of the connectors was loose enough to cause the observed symptom -- maybe as the P/S warms up, something expanded enough to change how snug one or more of the connections was, resulting in a gradual but inexorable loss of function. I dunno.
This is, FWIW, my best guess as to the guilty party (circled, see arrow)
-- but, of course correlation does not imply causation, so I really don't know why... but I sure was (am!) tickled to have a working HD tuner.
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Nice, glad to hear it's working now!
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yeah, me, too... of course, I feel like a moronic sloth.
It sounds good, too -- a little Kodachrome-y (brighter than life, so to speak) but great stereo and kind of intense bass compared to any of the other tunas in the house (which does include a couple-three
pretty good ones, albeit no Accuphase-level stuff).
I am currently using it with a rather nice base-loaded ss whip FM antenna made, as I understand it, by the OEM for the Magnum Dynalab FM whip antenna (these guys, IIRC: https://www.metzantennas.com/marine-antennas-leisure/ ). Of course, I have it leaning unobtrusively in a corner, next to one of the Frankenaltecs.
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Glad you got it working. Plenty of room inside to put some nice audiophile grade coupling capacitors in the output stage. If a service manual was available, that is.
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SeleniumFalcon wrote: »Glad you got it working. Plenty of room inside to put some nice audiophile grade coupling capacitors in the output stage. If a service manual was available, that is.
I cannot imagine the SM is (available) -- but I also figure that sussing out the (analog) output stage wouldn't be too difficult.
To the best of my knowledge, no one ever tweaked these as they did the aforementioned Sony (at least, to the point of a cottage industry developing).
I haven't really listened to it as an analog tuner. I do note that the (analog) output is "hotter" than the (mostly) vintage tuners here, so one's ear is drawn to it in a non-level-matched A/B comparison irrespective of how it sounds. I also suspect that the bass has been phattened up a bit for emphasis -- although I can't guarantee that any of my reference points (nor WVPR's transmitter or audio chain) have "flat" bass response. I do know (i.e., I recall anecdotally) that many classic FM tuners had LF response specs that only extend(ed) to 30 or even 50 Hz.
[EDIT] Sangean, AFAIK, still sells an HD tuner; the HDT-20. It is not inexpensive. I think it's reputed to be "better" than the HDT-1, but in what way(s) I don't know, nor have I ever encountered an HDT-20 in the wild.
EDIT: Pretty much an information gulch on the interwebz re: the HDT-20, although I did (finally) find it on Sangean USA's site https://www.sangean.com/products/product.asp?mid=198&cid=3 The HDT-20 is still available from the rainforest products supplier online and Wally World, too -- nothin' about it on any Sangean site, though. This is reputed to be a photo of the innards of the HDT-20. Must be the Gertrude Stein signature model.
There's no "there" there.
I did stumble across a technical (!) review of the HDT-1, though, including this (on-topic!) tidbit.The audio output network consists of 2.2kΩ in series with 10 µF for each channel, with .001 µF across the RCA jacks.
Post edited by mhardy6647 on -
I bet that 10uF is the Leonidas of improved fidelity.
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Hmm... maybe a coupla nice 10 uF oilers in there?
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Some of the Russian PIO capacitors are good sounding and not too terribly expensive. Nice and warm like a Moscow sauna.
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SeleniumFalcon wrote: »Some of the Russian PIO capacitors are good sounding and not too terribly expensive. Nice and warm like a Moscow sauna.
Yup, the coupling caps in my Fisher 500C are Russian (maybe even Soviet) PIOs.
(and not that I can find a photo of the underpinnings now...)
Here's the outside of it -- the 500C's currently a shelf queen but it is fully restored and is a nice sounding bit of hardware. The Sansui 1000A under it -- well, it is semi-rehabbed. I bought it for a good price but have never turned it on, and I don't have the heart to gut it for the OPTs (which are reputed to be quite good).
DSC_9817 by Mark Hardy, on Flickr
