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"pfjw@aol.com" <peterwieck33@gmail.com>: Jul 31 10:25AM -0700 On Tuesday, July 31, 2018 at 10:27:25 AM UTC-4, Mr. Man-wai Chang wrote: > > really short--probably tens of microseconds.  That helps a lot.   > And you are not wearing those handheld laser scanners like a VR > glass/helmet ...oh well... Um....   http://www.lasersafetyfacts.com/resources/Spreadsheet---laser-classes.pdf   Some useful information on laser classes.   And, yes, there are safety standards for VR glasses.   https://www.fi.edu/virtual-reality/product-safety-information   Peter Wieck Melrose Park, PA

"Mr. Man-wai Chang" <toylet.toylet@gmail.com>: Aug 01 11:09PM +0800 >> glass/helmet ...oh well... Um....   > http://www.lasersafetyfacts.com/resources/Spreadsheet---laser-classes.pdf   > Some useful information on laser classes.   Thanks   > And, yes, there are safety standards for VR glasses.   > https://www.fi.edu/virtual-reality/product-safety-information   Thanks.   -- @~@ Remain silent! Drink, Blink, Stretch! Live long and prosper!! / v \ Simplicity is Beauty! /( _ )\ May the Force and farces be with you! ^ ^ (x86_64 Ubuntu 9.10) Linux 2.6.39.3 不借貸! 不詐騙! 不賭錢! 不援交! 不打交! 不打劫! 不自殺! 不求神! 請考慮綜援 (CSSA): http://www.swd.gov.hk/tc/index/site_pubsvc/page_socsecu/sub_addressesa

"pfjw@aol.com" <peterwieck33@gmail.com>: Jul 31 10:19AM -0700 Gonna chime in on the out-of-sync thing. Here in the office, I stream WRTI on the computer, despite the wretched sound, as the radio is not reliable. I am 15' underground and dead-center in a city-block large hospital complex. But those few times I can get WRTI on FM, the stream is about 1/2 second behind the OTA signal. So something causing cross-talk, or something going out-of-sync and affecting OTA signal makes perfect sense.   Peter Wieck Melrose Park, PA

Terry Schwartz <tschw10117@aol.com>: Jul 31 10:59AM -0700 > Gonna chime in on the out-of-sync thing. Here in the office, I stream WRTI on the computer, despite the wretched sound, as the radio is not reliable. I am 15' underground and dead-center in a city-block large hospital complex. But those few times I can get WRTI on FM, the stream is about 1/2 second behind the OTA signal. So something causing cross-talk, or something going out-of-sync and affecting OTA signal makes perfect sense.   > Peter Wieck > Melrose Park, PA   In my house -- DirecTV is about 8 seconds behind broadcast.

dplatt@coop.radagast.org (Dave Platt): Jul 31 11:37AM -0700 > This went on for at least 5 miles, at least 10 minutes.   > It was nearly impossible to tell what was being said.   > How could this happen?   One possibility is that the station has one or more "repeater" transmitters on the same frequency, intended to increase its coverage area. The repeaters would be getting a feed of the stations's audio signal through some sort of dedicated link... and if this link is digital it might very well have a significant amount of latency and buffering.   If you were then driving through a "fringe reception" area, where your radio was receiving nearly-equal-strength signals from the primary tranmitter and a repeater transmitter, you could have heard an overlapping mix of audio from the two. FM receivers will typically "capture" one or the other signal, if one is stronger than the other by a couple of dB (the "capture ratio") but you can end up with a non-capture situation if both signals are very close in strength. The audio might have fluttered back and forth between the two as you drove, as the result of "picket fence" variations in the signal strengths of the two signals. Yeah, that would result in a rather unintelligible signal.   And... aha! Baltimore 88.1 is WYPR, and according to Wikipedia, they have a simulcast transmitter on the same frequency operating as WYPF in the Frederick/Hagerstown area. Westminster is just about equidistant from Frederick and Baltimore. WYPF's transmitter is in the forest just north of Frederick, while WYPR's is near Druid Hill Park is Baltimore.   So, that's my guess - fringe-area signal overlap, with one of the two signals having a one-second audio delay in its transmission path that the other signal does not have.

micky <NONONOmisc07@bigfoot.com>: Jul 31 04:16PM -0400 In alt.home.repair, on Tue, 31 Jul 2018 07:50:24 -0700, Jeff Liebermann   >On Tue, 31 Jul 2018 07:12:49 -0700, Bob F <bobnospam@gmail.com> wrote:   >>Very likely an out of sync repeater. It looks like they have 2 repeaters. >>http://www.wypr.org/your-public-radio-fcc-public-file   You almost convinced me of this, but Jeff reminded me... and then what he said convinced me you are right too. > studio is in the Charles Village neighborhood of > northern Baltimore, while its transmitter is in > Park Heights.   It's about 1200 feet from TV Hill, where almost all the tv xmitters are.   > The station is simulcast in the > Frederick and Hagerstown area on WYPF (88.1 FM) and   This doesn't yet solve the current question but it does answer another I never posted.   WYPR's reception is strong in Baltimore and its suburbs, but west, northwest, north of the suburbs, or all 3, the reception is weak and it's actually easier to get the NPR station in DC, maybe 40 miles farther south. I wrote to YPR about this one time but they misunderstood my letter.   So a few weeks ago I was south of Hagerstown, which is 70 miles or so west of Baltimore, and amazed to get WYPR. Now I realize I was getting WYPF, only 20 miles away. I knew about that station but not that it was on the same frequency. There are occasional announcements about all the stations that play the same programming, but they don't include the frequencies.   > in the Ocean City area on WYPO (106.9 FM).   I've listened to that too when I'm in southern Delaware.   >stations. Since KYPR and WYPF are both on 88.1 and fairly close to >each other, my guess(tm) is that their transmit frequencies are both >phase locked to some common reference,   Is that because if they weren't, one could be a half wave out of sync, and where both could be received, one would cancel out the other?   But the syncing failed for 10 minutes? And it was working other times I was in on that same road.   It turns out I was only 27.6 miles from the WYPF transmitter: https://www.google.com/maps/place/39%C2%B029'31.4%22N+77%C2%B029'59.0%22W/@39.4957541,-77.2810124,11z/data=!4m5!3m4!1s0x0:0x0!8m2!3d39.492045!4d-77.499709?hl=en   And it's 25.2 miles from the YPR xmitter. Part of the time, since I was moving, the distances were even closer.   >adjusted for identical delays. In other words, they're setup for >simulcast. However, that's a guess(tm) because I'm in a rush and >don't have time to read exactly what they're doing.   Any other ideas since you're back.

jurb6006@gmail.com: Jul 31 01:56PM -0700 Hold on a minute here. You can't just throw 2 signals through the IF strip and then the limiter. the signal would be a mess and neither would be intelligible.   Or would it ? Do digital FM detectors have the capability to do that ? Pretty sure a quadrature detector doesn't. In fact the limiter stage would be one of the main things making a mess out of the signal. That assumes that no earlier stage has clipped.   It can't be the image frequency because the same thing would happen, plus the fact that even at 87.9, the bottom of the band, the image frequency is 21.4 MHz apart. So like 87,9 + 21.4 is 108.3 on a band that ends at 107.9. Or if converted the other way, 107.9 - 21.4, still off the commercial FM band.   Still only 1 carrier makes it to the detector unscathed. It may not seem logical but that means the only way is be 2 signals hetrodyning. That is not to say that there is not a carrier out there that doesn't belong.   Am I wrong here ? Two carriers ? Just how would that work ?

dplatt@coop.radagast.org (Dave Platt): Jul 31 02:46PM -0700 In article <6b6bc94f-58dc-45d0-accd-db46a91c776f@googlegroups.com>, >Hold on a minute here. You can't just throw 2 signals through the IF strip and then the limiter. the >signal would be a mess and neither would be intelligible.   The signal does tend to be a mess, but you can end up with semi- intelligible audio, especially if you're moving, and the relative strengths of the two signals are varying a lot.   >Am I wrong here ? Two carriers ? Just how would that work ?   Well, here's how I see/understand it.   Both RF signals come through the front end and the mixer. The signal entering the first part of the IF strip is a down-mixed (10.7 MHz) combination of the two, with the relative IF strengths of the two being proportional to the corresponding RF signal strengths.   As this "combination" signal goes through the first part of the IF strip, it's amplified linearly... nothing distinguishes the two signals.   The interesting thing happens when the amplified IF signal is strong enough to limit. This is where the stronger signal wins (usually).   If one RF/IF signal is a lot stronger than the other (say, 10 dB or more), it's the one which limits. The detector/discriminator "sees" only this signal - the other one's contributions are too small to be detected - the detector is fully "captured". You hear the audio from this signal.   If the difference is smaller (say, 2 dB), the stronger signal limits and "captures" the detector and you hear its audio. However, the presence of the weaker signal in the detector input can perturb the detector enough to have some audible effect... an increase in distortion, or a faint "growling" sound. In the ham FM-repeater community we call this "doubling". As the difference between the signals grows less, and you fall towards the detector's "capture ratio threshold", the doubling growl/distortion grows worse.   When the two signals are of nearly the same strength, neither signal is detected properly... you either hear silence, or nothing but doubling growl/buzzing.   Now, consider the case the OP was talking about, where he's driving (not stationary). Under these conditions, the RF paths from the transmitters to his radio are constantly changing. It's quite common for there to be a large amount of signal-strength variation, from moment to moment... variations of 10 or 20 dB or more are not uncommon, due to multipath cancellations and reinforcements, reflections and diffractions, etc.   When listening to a single transmitter of sufficient strength, you don't notice this at all - with enough IF gain, the detector still gets a fully-limited signal and there's no noise.   When listening to a single transmitter with a weaker signal, you hear "picket fencing" - bursts of noise and distortion each time the signal strength drops too low, and the detector no longer gets a clean, limited signal.   Now, throw in a second transmitter, also weaker, in a different direction. The signals from the two transmitters will be picket-fencing in a completely un-correlated manner, because they're coming from different directions.   At one instant, one may be strong and the other weak, and you hear the first signal. A moment later, you've moved 50 feet, and the opposite is true - A is weak, B is strong, and you hear B. Somewhere in between those two locations, the signal strengths were nearly equal, neither captures the limiter, you hear neither cleanly (just silence, or a burst of noise and buzzing, or etc.).   In effect, the audio ends up "chopping" back and forth between the two transmitters' signals, at a rate of anywhere up to multiple times per second, with noise and distortion thrown in during the chopping.   That is, I think, what the OP was hearing. I've heard essentially the same effect when crossing the boundary between the service areas of two different (utterly unrelated) FM stations on the same channel. In this case the audio programs were completely different - one was not a delayed version of the other - but the RF issues were the same.

Jeff Liebermann <jeffl@cruzio.com>: Jul 31 05:37PM -0700 On Tue, 31 Jul 2018 16:16:40 -0400, micky <NONONOmisc07@bigfoot.com> wrote:   >>>http://www.wypr.org/your-public-radio-fcc-public-file   >You almost convinced me of this, but Jeff reminded me... and then what >he said convinced me you are right too.   Well, I did make a few minor mistakes. The terms "repeater", translator", and "simulcast" have very specific meanings, which I managed to mangle. Part of the problems is that I don't know what WYPR is doing with both transmitters on 88.1MHz. Are they simulcast transmitters, or is WYPF a repeater? Dunno and still to lazy/busy to do the research.   >This doesn't yet solve the current question but it does answer another I >never posted.   Sorry, but my crystal ball is being overhauled and I can't provide answers to unasked questions without it.   >WYPR's reception is strong in Baltimore and its suburbs, but west, >northwest, north of the suburbs, or all 3, the reception is weak...   These might help: <https://radio-locator.com/info/WYPR-FM> <https://radio-locator.com/cgi-bin/patg?id=WYPR-FM>   <https://radio-locator.com/info/WYPF-FM> <https://radio-locator.com/cgi-bin/patg?id=WYPF-FM>   <https://radio-locator.com/info/WYPO-FM> <https://radio-locator.com/cgi-bin/patg?id=WYPO-FM>   Notice that the Google Maps are gone, thanks to a Google fee increase.   >So a few weeks ago I was south of Hagerstown, which is 70 miles or so >west of Baltimore, and amazed to get WYPR. Now I realize I was getting >WYPF, only 20 miles away.   If they were really simulcasting (phase locked RF and audio), you would not be able to tell which one you were listing to.   >was on the same frequency. There are occasional announcements about all >the stations that play the same programming, but they don't include the >frequencies.   They should include the frequencies with the station identification. We have several local conglomerations of stations that take quite a while to identify all the stations that are simulcasting the same programming. For example: <https://www.kdfc.com/listen/kdfc-coverage-maps/> However, each of the 5 transmitters are on different frequencies.   >>phase locked to some common reference,   >Is that because if they weren't, one could be a half wave out of sync, >and where both could be received, one would cancel out the other?   Yep, or something like that. Without phase locked simulcasting of the transmitters, there would be a large number of dead spots and possibly some low frequency heterodyne tones.   >But the syncing failed for 10 minutes? And it was working other times >I was in on that same road.   The fact that you were moving is important. If the signal levels from each transmitter was roughly equal, you would be moving through zones where one or the other transmitter is stronger and "captures" the transmitter with the lesser signal. Since you were moving, the strongest transmitter will switch back and forth between the two stations erratically. Since something failed on the audio delay system, every time your receiver switched between the two stations, the audio would change accordingly.   >https://www.google.com/maps/place/39%C2%B029'31.4%22N+77%C2%B029'59.0%22W/@39.4957541,-77.2810124,11z/data=!4m5!3m4!1s0x0:0x0!8m2!3d39.492045!4d-77.499709?hl=en   >And it's 25.2 miles from the YPR xmitter. Part of the time, since I was >moving, the distances were even closer.   So, it's likely that the signal levels were roughly the same, which is ideal for creating the problem.   >Any other ideas since you're back.   Nope.   -- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558

"pfjw@aol.com" <peterwieck33@gmail.com>: Aug 01 05:13AM -0700 Y'all are making this far too complicated and inventing explanations other than a simple sync issue within the station itself. Could be as simple as a tech replacing a piece of equipment and dropping a jumper into the wrong jack. 10 minutes later - after the phones started ringing off the hook - it got fixed.   William of Occam suggested that we eschew needless complexity.   Peter Wieck Melrose Park, PA

N_Cook <diverse@tcp.co.uk>: Jul 31 06:31PM +0100 On 31/07/2018 16:34, Terry Schwartz wrote: >> a conductor break. Makes you wonder where all that plasticiser migrates >> to, presumably us , quite a bit.   > It outgasses..... to atmosphere. Just like the buildup of haze on the inside of your windshield after a hot summer. That's your dashboard, vinyl, carpeting, wire insulation, powder coated parts, upholstery, foam, virtually everything in your car's interior except the metal itself, condensing on the glass and every other surface. Good reason to keep the air flowing thru the vehicle as you drive, minimize the inhalation of those compounds. Gotta love that new car smell.   Do you happen to know what the oily or slimy stuff is, that coats old very flexible cables such as telephone movable extension cables, a bio-film or plasticiser like chemical ?

Terry Schwartz <tschw10117@aol.com>: Jul 31 10:56AM -0700 My assumption has always been household cooking grease. Any hard surface that doesn't purposefully get cleaned regularly in a house where actual cooking takes place seems to accumulate airborne cooking grease. It soaks into soft surfaces, but creates an oily film on everything else.   Used to make a lot of service calls into houses in certain ethnic neighborhoods. Bring TV sets back to the shop... first thing we did was wipe them down with glass cleaner. The ammonia in it worked much better than the "409" type cleaners of the day against cooking grease. Some sets were so greasy there was a real risk of dropping them on the way out of the house. Sometimes the line cords were literally furry with grease and accumulated dust. And the high voltage sections, even worse.   You may be referring to something else... that was just my observation.

The Real Bev <bashley101@gmail.com>: Jul 31 12:34PM -0700 On 07/31/2018 10:31 AM, N_Cook wrote:   > Do you happen to know what the oily or slimy stuff is, that coats old > very flexible cables such as telephone movable extension cables, a > bio-film or plasticiser like chemical ?   We used to see a lot of icky goo back when we were digging through stuff at electronic surplus stores. The military used "cosmoline" on a lot of stuff it wanted to protect (or maybe still does). Core dump complete.   -- Cheers, Bev Red ship crashes into blue ship - sailors marooned.

"Ian Field" <gangprobing.alien1@virginmedia.com>: Jul 31 09:33PM +0100 "N_Cook" <diverse@tcp.co.uk> wrote in message news:pjpo2r$380$1@dont-email.me... > the blue body gone hard with age and causing stress to cable and then a > conductor break. Makes you wonder where all that plasticiser migrates to, > presumably us , quite a bit.   If you're going to use a Cooper Tools iron - keep a cheap Antex X25 iron ready to hand for all the times it'll need repairing.

Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net>: Jul 31 05:54PM -0400 On 07/31/2018 03:34 PM, The Real Bev wrote:   > We used to see a lot of icky goo back when we were digging through stuff > at electronic surplus stores.  The military used "cosmoline" on a lot of > stuff it wanted to protect (or maybe still does).  Core dump complete.   Including surplus jeeps. ;) (Car Talk nostalgia.)   Cheers   Phil Hobbs   -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics Briarcliff Manor NY 10510   http://electrooptical.net http://hobbs-eo.com

Fox's Mercantile <jdangus@att.net>: Jul 31 05:57PM -0500 On 7/31/18 3:33 PM, Ian Field wrote: > If you're going to use a Cooper Tools iron - keep a cheap Antex > X25 iron ready to hand for all the times it'll need repairing.   I bought a Weller WES51 back in 2001, it's been in constant service since then. I have a second WES51 I use occasionally (off site.)   The WES51 was a replacement for the TCP that I'd had since 1985. It dropped dead while I was at a field service site, so I didn't bother to "What's wrong with this?" at the time. I just bought a new station. After I got home, I fixed the TCP. it still works and is the "other" back up iron that's home in the garage now rather than in the shop.       -- "I am a river to my people." Jeff-1.0 WA6FWi http:foxsmercantile.com

N_Cook <diverse@tcp.co.uk>: Aug 01 08:51AM +0100 On 31/07/2018 23:57, Fox's Mercantile wrote: > new station. > After I got home, I fixed the TCP. it still works and is the "other" > back up iron that's home in the garage now rather than in the shop.   My one came via auction from one-time Ferguson production line at Gosport, England. Jane in 1986 melted here name and date on the front plastic. I only switch it on when required, heat-up time allows me to check I'm to mentally check the IC is in the right wat round or whatever. One tip that certainly avoided the barrel cracking at the hot end, transistor tab mount insulator, one above and one below the flange of the 3 fixing screws, may have helped such long service. I make my own long conical tips from believed Solon ancient iron tips cut down and salvaged magnastat fitted over a stub of copper clinker boat clenching nail.

N_Cook <diverse@tcp.co.uk>: Aug 01 08:54AM +0100 On 31/07/2018 18:56, Terry Schwartz wrote:   >> Do you happen to know what the oily or slimy stuff is, that coats old >> very flexible cables such as telephone movable extension cables, a >> bio-film or plasticiser like chemical ?   I recently dumped a box of telephone stuff ,been in a shed for 20 years, perfectly ok when put in there. All the leads were this manky gooey coating, no cooking in my shed of coarse. I'm reminded of the black goo in tape recorders/VCRs when a rubber band perishes to goo, and all the other bands get the same contagion and fail , but not necessarily to sticky goo

jurb6006@gmail.com: Jul 31 01:58PM -0700 >"Aren't drug store pyrex glass tubes used for smoking rock cocaine? "   I can see it now...   "Dude, you gotta load that kush into this beam power tube, it's a blast".

The Real Bev <bashley101@gmail.com>: Jul 31 02:03PM -0700 >>"Aren't drug store pyrex glass tubes used for smoking rock cocaine? "   > I can see it now...   > "Dude, you gotta load that kush into this beam power tube, it's a blast".   Is everybody here too young to know what a drugstore tube tester is? Damn! The drugstore testers were crap; you needed to go to the REAL electronics store and use the REAL tube tester if you were serious.   I hope the guy is trying to put together an old one, complete with its proper complement of replacement tubes. We shouldn't forget our history.   -- Cheers, Bev Horn broken. Watch for finger.

Ralph Mowery <rmowery28146@earthlink.net>: Jul 31 06:20PM -0400 In article <pjqiqb$ksl$1@dont-email.me>, bashley101@gmail.com says... > electronics store and use the REAL tube tester if you were serious.   > I hope the guy is trying to put together an old one, complete with its > proper complement of replacement tubes. We shouldn't forget our history.   Many were set so that a tube that was on the low end of being good would show up as bad. More sales that way.   It always paid to plug in the new tube just to see how well it tested. If not much difference, keep the old one.

Fox's Mercantile <jdangus@att.net>: Jul 31 05:59PM -0500 On 7/31/18 4:03 PM, The Real Bev wrote: > I hope the guy is trying to put together an old one, complete with its > proper complement of replacement tubes.  We shouldn't forget our history.   That's exactly what Terry is up to.     -- "I am a river to my people." Jeff-1.0 WA6FWi http:foxsmercantile.com

Terry Schwartz <tschw10117@aol.com>: Jul 31 04:16PM -0700 On Tuesday, July 31, 2018 at 5:59:23 PM UTC-5, Fox's Mercantile wrote: > Jeff-1.0 > WA6FWi > http:foxsmercantile.com   Thanks Jeff.   I am filling the drawers : https://www.flickr.com/photos/32165280@N02/albums/72157674341385913   32 tubes to go.   Terry

The Real Bev <bashley101@gmail.com>: Jul 31 08:08PM -0700 On 07/31/2018 04:16 PM, Terry Schwartz wrote:   > Thanks Jeff.   > I am filling the drawers : https://www.flickr.com/photos/32165280@N02/albums/72157674341385913   > 32 tubes to go.   Excellent!     -- Cheers, Bev When your only tool is a hammer, everything looks like a thumb.

bruce2bowser@gmail.com: Jul 31 10:14PM -0700 On Tuesday, July 31, 2018 at 5:03:10 PM UTC-4, The Real Bev wrote: > electronics store and use the REAL tube tester if you were serious.   > I hope the guy is trying to put together an old one, complete with its > proper complement of replacement tubes. We shouldn't forget our history.   A lot of this stuff is down-right microscopic today. Or will be pretty soon.

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