Re: [Repeater-Builder] Re: New wind generator group
It is designed as a technical group. Thank You, Ian Wells, Kerinvale Comaudio, 361 Camboon Road.Biloela.4715 Phone 0749922574 or 0409159932 www.kerinvalecomaudio.com.au ---Original Message--- From: skipp025 Date: 12/24/08 12:23:38 To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Re: New wind generator group Is it a technical or political group? :-) Hi there .Just a quick email to let you know that I have formed a new group on yahoo for discussion about wind generators. http://groups.yahoo.com/group/windgenerators
[Repeater-Builder] SuperSquelch-MK4 - Matt KC7GSA
Hi, Is Matt Krick, KC7GSA a member of this group? If so could he please advise if he has a board design for his SuperSquelch MK4. I have a need for a couple of these and before I design one if there is one already could a please request copy of it? Thanks for the info, and all have a Merry Christmas, midnight is only 10mins away here and still getting ready for the family to arrive. Regards Kevin, ZL1KFM. Get Skype and call me for free. sparc_nz Description: Binary data
Re: [Repeater-Builder] Re: OT: Radios and Coms in TV and Movies
Check this site it may have some useful info. SD http://harrymarnell.net/ --- On Tue, 12/23/08, Albert hitekgearh...@hotmail.com wrote: From: Albert hitekgearh...@hotmail.com Subject: [Repeater-Builder] Re: OT: Radios and Coms in TV and Movies To: Repeater-Builder@yahoogroups.com Date: Tuesday, December 23, 2008, 10:08 PM Wow Guys! This was exactly the kind of information I was looking for. I always think it is neat to hear a little history from people who have been there and done that. I will have to go back and reread all of the posts to soak all of it up. Thanks again --- In Repeater-Builder@ yahoogroups. com, Albert hitekgearhead@ ... wrote: I was wondering if anyone had links to any websites that talk about radios used in TV and Movies. What got me thinking about this was that I had been watching the old TV show Emergency on Netflix. (remember squad 51, rampart hospital, etc.) I know some of the stuff is just props but I thought some of it might be real equipment that I don't recognize. For instance one of the characters (Roy) often carries an HT into the hospital when they drop off a patient. I think it is an HT220 since it has a telescoping antenna, but might be a MT500. Thanks
[Repeater-Builder] Re: Astron P/S question
Have you contacted Astron directly? I blew mine up, yup, dangling keys touching one of the transistors and the case will let the smoke out in a hurry...and have an incredible heating effect on the key. º Afterwards, I called Astron and talked to a tech. He was excellent and walked me through various tests on the unit and what were considered probable parts failures along with recommended replacements and upgrades. I did as he suggested and after the parts were installed, he again walked me through a post install test sequence to assure it was working. It does and has worked well ever since with zero issues. The unit is quieter, doesn¡¦t bang so obnoxiously on start up and maintains excellent voltage stability. One of the last posts regarding voltages and some of the others regarding the SCR triggered a recall that this was one of the same areas of discussion I had with the tech about a year ago. May be worth a call, they seemed very nice and accommodating when I called in and may have had calls on what you are trying to remedy. A side note about the common transistors used on many of the Astrons, like the 20 and 50RM¡¦s I have, work great in the Motorola R100 repeater. If your R100 runs warm even without transmitting, power supply fails, or seems to act strange at times, try changing out the two power transistors mounted in the heat sink. Most will slide right out, some have a dab of over zealous solder to remove but the reward is a cold heat sink until it is put to work and even then, at a much reduced heat than before. Travis AA9NV --- In Repeater-Builder@yahoogroups.com, n9wys n9...@... wrote: For the learned group here. I know there has been some discussion on one the list regarding Astron Power supplies. Unfortunately, searching hasn't revealed what I am looking for, so I pose my query here and apologize in advance if this was a subject that was discussed at length in the past. I will describe my problem in detail, so forgive me for being so verbose right off the bat; but I figure if I provide a lot of info now, it will avoid a lot of question and answer exchanges later in order to get an understanding of my problem. I have a UHF ham repeater system (TKR-820 as transmitter, MICOR SpectraTAC receiver and comparator, Astron RM-70 Power Supply, and Crescend 150W P/A) that is experiencing issues with the power supply. Seems that when the repeater is on the air for any time (for example, over three minutes key-down) the power supply blows a fuse. The first time this happened, I changed out the P/S with a MICOR supply I had from a 100W continuous duty station. It also blew THAT fuse. The Astron supply that blew the fuse had two bad diodes in the rectifier, so that was repaired. There was nothing found wrong with the Motorola supply, other than the main fuse had blown. I took the PA back to Crescend, but they found nothing wrong with the P/A. The station was put back on the air with the repaired Astron supply. Was on the air for about two weeks, and failed again while I was talking to another ham. Went back to the tower and found the fuse blown again in the supply. I took the PA offline and brought it back to Crescend, told them of the issue with the P/S, and that I needed them to check the PA for problems. Their service tech called me and said he'd had the PA running on his workbench as we spoke, and had it transmitting for about 45 minutes with no problems - all operating within spec (~32A nominal - 38A max draw @ 165W output). After we talked some more, he said he'd leave it run all night. If it was OK, he'd ship it back. I got the PA back the following Tuesday. I put the station back on the air. In the meantime, I spoke with an engineer from Crescend who told me that they had some experience with RF getting into Astron supplies. so when I took the PA back to the tower, I put ferrites on the A+ and ground leads to the P/S from the PA. (There are about 10 wires altogether in the power cable going to the PA - two bundles of three A+, and four Grounds.) I put three ferrites altogether on the DC lines, and made three turns through the ferrites with each bundle. These were installed as close as physically possible to the power supply. I also put one turn on a ferrite for the entire bundle at the PA end. (Couldn't do more than that - was running out of cable length for hook-up.) I replaced the fuse again, and got the station back on the air. Worked for about 45 minutes (or long enough for me to be far enough away from the tower where I couldn't make a return trip that day) and promptly blew the fuse again. (Or so I suspect.) I haven't had a chance to go back to examine the cause of the failure this time - yet. Now - here's the WEIRD part. when I was at the tower with another tech and replaced the fuse the time before the last failure, we
Re: [Repeater-Builder] NHRC-Squelch Board
Bob, my impression (I did not make any measurements) was that the short squelch tail did not change any with the mod. I had a mixture of base station and mobile squelch modules in my base station repeaters, and the biggest problem I had was with the base station modules. One of the capacitors was completely missing in those modules (as pointed out in the mod instructions). Those modules with the missing capacitor were the ones with the worse problem when a noisy signal was dropping out intermittently with the multipath. My impression of the tail with a very weak signal was that the squelch stays open for about 200 msec when the signal goes away. I tried both the 3.3 uF and the 4.7 uF caps and could not tell much difference. Both worked out just fine. I did find several different layouts for the boards and had to verify the LSI chip part number and then trace the leads from the right pin back to the correct capacitor. But all responded OK to the capacitor when modified. 73 - Jim W5ZIT --- On Wed, 12/24/08, n...@no6b.com n...@no6b.com wrote: From: n...@no6b.com n...@no6b.com Subject: Re: [Repeater-Builder] NHRC-Squelch Board To: Repeater-Builder@yahoogroups.com Date: Wednesday, December 24, 2008, 12:46 AM At 12/23/2008 09:09, you wrote: For the GE Mastr II users following this thread, be sure to check the mod shown here: http://www.repeater -builder. com/ge/mastrIIsq uelchmod. html I have this mod in all the repeaters I have built and am very pleased with the operation. It resembles the dual squelch operation of the Micor in that it closes very fast with barely a click on a fully quieted signal, yet does not close during a mobile transmission that is picket fencing. I have not needed to use an audio delay module to have a very good sounding repeater with no long open squelch bursts. Any idea as to how much the short squelch tail is lengthened by this mod? Without the mod the G.E's short squelch is a bit longer than the Micor (~6 milliseconds for the Mastr II vs. ~2 for the Micor) Bob NO6B ,_._,___
[Repeater-Builder] Re: Astron P/S question
Laryn, If the power supply were a switching design, current foldback would occur. But, in the typical Astron RS-series linear supply, the firing of the SCR puts a bolted short on the output. As soon as the large capacitors on the output start to lose their charge, the regulator tries to maintain the output voltage by turning on the pass transistors to full conduction, quickly exceeding the current ratings of the transformer and rectifier diodes and blowing the fuse. Every time this has happened to an Astron RS supply (that I have personal knowledge of), it has blown the fuse. Every time. Odd that your experience is different. The fuse ratings are specified by Astron to ensure that they will blow under such conditions. Because of their (RS-series) relative instability in high-RF environments, I now install only Duracomm, Samlex, and Astron switching power supplies. Lightweight, very efficient, and very reliable. 'Nuff said. 73, Eric Lemmon WB6FLY --- In Repeater-Builder@yahoogroups.com, Laryn Lohman lar...@... wrote: snip Why is the fuse blowing? Shouldn't the crowbar firing cause simple current foldback? All of my Astrons do, and never blow fuses. My apologies if this has been brought up before... Laryn K8TVZ
[Repeater-Builder] Re: OT: Radios and Coms in TV and Movies
Actually, they did. By changing the PL tone that was sent from the 'med' radio, you changed what frequency the mobile transmitted on. WalterH --- In Repeater-Builder@yahoogroups.com, n...@... wrote: At 12/22/2008 10:21, you wrote: SNIP There was an Emergency episode where Gage DeSoto didn't like the instructions given by the orderly at Rampart over the med. radio (I believe they were told to use the defibrillator on someone they felt didn't need it), so they switched channels on that radio proceeded to get their instructions from St. Francis Hospital instead of Rampart. If that radio relayed through the squad radio I doubt they would have really had that capability. Bob NO6B
Re: [Repeater-Builder] Re: Astron P/S question
I don't disagree with you, but it seems odd to me. Doesn't Astron use the current fold-back feature of the 723? If they do, it should just foldback due to overcurrent. If they don't, well, the fuse is the only salvation. Chuck WB2EDV - Original Message - From: wb6fly wb6...@verizon.net To: Repeater-Builder@yahoogroups.com Sent: Wednesday, December 24, 2008 11:28 AM Subject: [Repeater-Builder] Re: Astron P/S question Laryn, If the power supply were a switching design, current foldback would occur. But, in the typical Astron RS-series linear supply, the firing of the SCR puts a bolted short on the output. As soon as the large capacitors on the output start to lose their charge, the regulator tries to maintain the output voltage by turning on the pass transistors to full conduction, quickly exceeding the current ratings of the transformer and rectifier diodes and blowing the fuse. Every time this has happened to an Astron RS supply (that I have personal knowledge of), it has blown the fuse. Every time. Odd that your experience is different. The fuse ratings are specified by Astron to ensure that they will blow under such conditions. Because of their (RS-series) relative instability in high-RF environments, I now install only Duracomm, Samlex, and Astron switching power supplies. Lightweight, very efficient, and very reliable. 'Nuff said. 73, Eric Lemmon WB6FLY
Re: [Repeater-Builder] Re: Astron P/S question
I think they do, but only if the supply is putting out current to the load and the current exceeds the value they've set for it. The crowbar firing definitely exceeds the current limit but it's so sudden and complete that the design and component values just cause the fuse to instantaneously blow. Bob M. == --- On Wed, 12/24/08, Chuck Kelsey wb2...@roadrunner.com wrote: From: Chuck Kelsey wb2...@roadrunner.com Subject: Re: [Repeater-Builder] Re: Astron P/S question To: Repeater-Builder@yahoogroups.com Date: Wednesday, December 24, 2008, 12:59 PM I don't disagree with you, but it seems odd to me. Doesn't Astron use the current fold-back feature of the 723? If they do, it should just foldback due to overcurrent. If they don't, well, the fuse is the only salvation. Chuck WB2EDV - Original Message - From: wb6fly wb6...@verizon.net To: Repeater-Builder@yahoogroups.com Sent: Wednesday, December 24, 2008 11:28 AM Subject: [Repeater-Builder] Re: Astron P/S question Laryn, If the power supply were a switching design, current foldback would occur. But, in the typical Astron RS-series linear supply, the firing of the SCR puts a bolted short on the output. As soon as the large capacitors on the output start to lose their charge, the regulator tries to maintain the output voltage by turning on the pass transistors to full conduction, quickly exceeding the current ratings of the transformer and rectifier diodes and blowing the fuse. Every time this has happened to an Astron RS supply (that I have personal knowledge of), it has blown the fuse. Every time. Odd that your experience is different. The fuse ratings are specified by Astron to ensure that they will blow under such conditions. Because of their (RS-series) relative instability in high-RF environments, I now install only Duracomm, Samlex, and Astron switching power supplies. Lightweight, very efficient, and very reliable. 'Nuff said. 73, Eric Lemmon WB6FLY
Re: [Repeater-Builder] Re: Astron P/S question
I have an old Bullet power supply built from a kit (anyone remember those?) that uses the 723. You can short the output time and time again and it simply folds back. No harm, no foul. That's why I was wondering. I've never tried that with an Astron (and probably won't now). Chuck WB2EDV - Original Message - From: Bob M. msf5kg...@yahoo.com To: Repeater-Builder@yahoogroups.com Sent: Wednesday, December 24, 2008 2:32 PM Subject: Re: [Repeater-Builder] Re: Astron P/S question I think they do, but only if the supply is putting out current to the load and the current exceeds the value they've set for it. The crowbar firing definitely exceeds the current limit but it's so sudden and complete that the design and component values just cause the fuse to instantaneously blow. Bob M.
