- Two rsignals at same time, 88.1 where - 2 Updates
- Weller magnastat soldering iron problem - 3 Updates
| Jeff Liebermann <jeffl@cruzio.com>: Aug 01 08:27AM -0700 On Wed, 1 Aug 2018 05:13:48 -0700 (PDT), "pfjw@aol.com" >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. I doubt if more than few listeners heard the problem. In order to hear both transmitters switching back and forth, the listener would need to be: 1. Roughly equal distant from both stations or in an area where the signal strengths are about the same. 2. In a moving vehicle, train, bus, or whatever. 3. Have a cell phone handy with which to phone the station. 4. Have a web browser handy to lookup the phone number: <http://www.wypr.org/contact-us> 5. Be sufficiently experienced with such problems to be able to explain the problem to the low technical level person who answers the phone, and at a high level should someone be available that understands the problem. 6. Be able to explain why the various OTA station monitors show that everything is just fine and both transmitters are on the air. 7. Be able to explain why so few other people have called in the problem. I've found that stations do not act on such things unless there are a large number of calls, or they get a call from a sponsor. >William of Occam suggested that we eschew needless complexity. He was wrong. Todays fashion is to target one's writing to the lowest level of intelligence and expertise that one might expect the document to be read. If someone is writing for a engineers with FM broadcast experience, it would look very different if they were writing for the GUM (great unwashed masses). The best advice I've seen is to write for those that are competent in their field of expertise, not necessarily in yours. In this case, the problem isn't very complicated to understand if one has some experience with FM capture effect, simulcast techniques, FM simulcast, repeaters, translators, FCC FM 60dBu contours, digital vs analog FM receivers, and possibly how HD Radio works. I didn't mention the possible HD RADIO problem because I thought it was unlikely. Yet the symptoms are similar. WYPR broadcasts on 88.1 (main FM channel), 88.1-1 (HD1 news and talk), 88.1-2 (HD2 BBC world news), and 88.1-3 (HD3 classical music). During commercial breaks and other interruptions, stations sometime fill in the dead air with audio from one of the digital sub-channels. There is a delay between the main analog FM audio and the delayed digital version, in this case on HD1. Stations with this arrangement usually have some way to adjust this delay so that switching between the analog audio and HD1 does not result in an obvious delay. If the listener is in a moving vehicle, and has the radio switched to HD1, the signal will drop out on HD1 in fringe areas causing the receiver to revert back to the main FM audio. This is particularly irritating because many HD Radio receivers do not have a setting that forces the receiver to stay on HD1 and not switch to the main analog channel. It's possible that this might have been the problem, but I can't tell from here without more details. So, what have we learned here? 1. Simple explanations are fine for the GUM but not so useful if you want to understand what had happened and how it works. 2. If you want to understand something, you have to dig deep, really deep. 3. RF is magic. 4. Nothing is simple. 5. If something seems too complicated, ask questions or Google for understanding. Don't just complain that it's too complexicated. -- 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 09:28AM -0700 On Wednesday, August 1, 2018 at 11:27:52 AM UTC-4, Jeff Liebermann wrote: > >wrong jack. 10 minutes later - after the phones started ringing off > >the hook - it got fixed. > I doubt if more than few listeners heard the problem. Or, every listener did, as the problem was within the station and not due to some wild concatenation of unusual forces. The entire premise of a complicated answer requiring vast research is that it ain't necessarily so. What I am suggesting is that an acorn falling from a tree does not require the sky to be falling, Chicken Little notwithstanding. Sometimes, it is simply (and merely) an acorn. Peter Wieck Melrose Park, PA |
| Jeff Liebermann <jeffl@cruzio.com>: Aug 01 08:54AM -0700 On Tue, 31 Jul 2018 17:57:48 -0500, Fox's Mercantile <jdangus@att.net> 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. In about 1975, I bought a large box full of Weller WTCPT, WTCPL, TC-201, etc soldering irons, bases, cords, parts, and goodies. I think I paid about $20 for everything. I've never bothered to count, but I think I've rebuilt about 10 irons out of the pile, and probably have parts for 5-10 more. A big irritation is that I have buy tips and sponges. I have at least one iron on every workbench, including the kitchen table. These are not the best irons available, but they seem to last forever and are fairly easy to fix when they decide its time to break. Along the way, I've purchased a few imported soldering irons. They're much cheaper than Weller and do work well enough. Rather than give my friends one of my good Weller irons, I give them the imported irons. As for the original problem, I can't tell what's broken from here. An ohmmeter will tell if it's a broken cable, bad switch contacts, or blown heater. The little plastic twist locks sometimes fall apart. Check for intermittent connectors where the cord enters the base. My guess(tm) would be the contacts. Unwrap the yellow kapton tape. The plastic shell will fall apart. Clean the contacts. If the contacts are badly pitted, file down the peaks. Re-silver if necessary. Replace the tape, reassemble, check for continuity, and you're done. <http://bama.edebris.com/download/weller/wtcpl/WTCPL%20Tech%20Sheet.pdf> -- 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 |
| Jeff Liebermann <jeffl@cruzio.com>: Aug 01 09:13AM -0700 >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 ? It depends on the age. Today, most PVC and rubber cables use phthalates or ortho-phthalates as a plasticizer to soften the plastic and make it flexible. Before about 1930, it was castor oil or vegetable oil. Yech. <http://wwwcourses.sens.buffalo.edu/ce435/2001ZGu/Phthalate_Plasticizers/PhthalatePlasticizersReport.htm> (Yes, I know the formatting sucks, but the info looks good). There are also non-phthalate plasticizers introduced: <https://www.eastman.com/Pages/ProductHome.aspx?product=71072819> The SDS data says it's 98% bis(2-ethylhexyl) terephthalate which makes me wonder why they claim it's non-phthalate. -- 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 |
| ggherold@gmail.com: Aug 01 09:23AM -0700 On Tuesday, July 31, 2018 at 11:34:07 AM UTC-4, 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. Huh, I always wondered where the 'haze' on the inside of my car window came from. Thanks. George H. |
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