Re: [Repeater-Builder] Motorola radios and Zetron 37 controller - additional
Maybe awesome radios, one should try and get hold of the programing software, it's a nightmare Marcus On Wed, Jun 23, 2010 at 3:03 AM, Tony KT9AC kt...@ameritech.net wrote: Sorry, and apologies for the extra email, just wanted the info to be complete. The 3 near the end is the range - 1=403-433, 2=not used, 3=438-470, 4=470-490, 5=490-512 Awesome radios. On 06/22/2010 09:59 AM, Tony KT9AC wrote: I think you mean M44GMC29C3AA's - tons for sale on eBay typically around $50 each. M = mobile 4 = 25-40W (20% duty cycle) 4 = 438-470 Mhz GMC = this series (actually German Maxtrac is where these came from) 2 = wideband deviation (5Khz, where a 0 would be 2.5Khz narrowband - not switchable, one or the other) 9 = expanded logic board - 16 channel typical, MDC1200, QCII, etc C = model revision AA = not used, just character filler Are you power cycling the radios or the Zetron? Tony On 06/22/2010 08:45 AM, Larry Horlick wrote: Is the Zetron that's locking up? I had a similar problem with a Zetron 45B. lh On Tue, Jun 22, 2010 at 5:53 AM, Joel ag...@cyberbest.com wrote: We have 2 repeaters that are more or less the same. One is on 2 meters and the other is on 440. They both exhibit the same problem, they lockup after a while and then need to be power cycled. They ran for years without issue. We have the Instruction manual for the Zentron controller, but nothing on the radios. The 440 radios are Motorola M44GM29C3AA's back to back. That's the only model number on the radios. Does anyone have any information on them? A Google search shows 2 Chinese sites having them for sale on e-bay, that's it. Seems strange. Any information would be greatly appriciated, Joe Loucka -- AG4QC
[Repeater-Builder] Re: Motorola radios and Zetron 37 controller
Hi Group, The first thing to monitor is the TX power does it drop when it locks up? After years the GM300's are prone to problems with loose connectors dealing with temp changes. Read the article on the repeater-builder's website concerning the GM300 and Maxtrac about the VCO adjustments also works for the Maratrac series. Ryan n3ssl
[Repeater-Builder] Re: Antenna Experience Needed!
If you look at many commercial sites, many are pretty close together. I am not saying that is good or bad, but apparently it works for them. Especially if it is on different bands. You can take a close up look at our repeater(s) install; http://disneycrazy.smugmug.com/Other/New-Repeater-Site/7943953_gF4Q3 We have 2 top mounted antennas (db224 and db420) at 300ft, a 2/440/1.2 Diamond and db224 on a side arm at 250ft and then db224 and db420 at 200ft (side arm mount). Close up pictures on all are on the site. The top mounted antennas are 2 side mounts that are HUGE in comparison to what db sells for side mounting those antennas. The vertical pipe is probably 6 to 8 OD. The arms are 3ft and then puts the db224 and db420 at 6ft apart at the top. Note-these top mounted antennas are not on a side arm you normally see cell phone antennas on. 73, Robert KD4YDC --- In Repeater-Builder@yahoogroups.com, n2len n2...@... wrote: I was given the opportunity of placing 3 repeater antennas at the very top of a 180 foot cellphone monopole tower. A horizontal arm mounted on the top of the monopole will allow the mounting of my 3 repeater antennas. Horizontal separation should be no less than 6 feet apart from each other. Here are my 2 questions: We will be mounting 2 meter, 220, and a 440 repeater antennas. 1: What do you recommend between a choice of either RFS or Telewave Superstation Master Type or DB224E Dipole type for top mounting? Pros and Cons of each. I heard many stories about cracking for both. Wind load... These antennas will be top mounted! Located in the Catskill Mtns, Snow Ice are problems. High winds etc 2: What do you feel about the pattern/reflection with having 3 verticals atop next to each other spaced say 6 feet apart? Thank you for your input: Len N2LEN
Re: [Repeater-Builder] Re: Antenna Experience Needed!
My vote would be for folded dipole arrays. Sinclair, Comprod, Telewave and Andrew make good ones. I have seen far too many failures with fiberglass collinear antennas - lighting and particularly internal failure causing untold noise generation to the repeater itself as well as to every radio service nearby. I've never seen a fiberglass one that stood a direct hit but have seen folded dipoles that did. I'd say at least a 3:1 failure rate, maybe higher. That said, any can fail. Chuck WB2EDV We will be mounting 2 meter, 220, and a 440 repeater antennas. 1: What do you recommend between a choice of either RFS or Telewave Superstation Master Type or DB224E Dipole type for top mounting?
[Repeater-Builder] Re: Antenna Experience Needed!
My choice would be the DB-224 type. Sid WA4VBC --- In Repeater-Builder@yahoogroups.com, Chuck Kelsey wb2...@... wrote: My vote would be for folded dipole arrays. Sinclair, Comprod, Telewave and Andrew make good ones. I have seen far too many failures with fiberglass collinear antennas - lighting and particularly internal failure causing untold noise generation to the repeater itself as well as to every radio service nearby. I've never seen a fiberglass one that stood a direct hit but have seen folded dipoles that did. I'd say at least a 3:1 failure rate, maybe higher. That said, any can fail. Chuck WB2EDV We will be mounting 2 meter, 220, and a 440 repeater antennas. 1: What do you recommend between a choice of either RFS or Telewave Superstation Master Type or DB224E Dipole type for top mounting?
[Repeater-Builder] Re: Motorola radios and Zetron 37 controller
This is a regular issue with many controllers, especially Trident Raiders several Comm Spec units, and Motorola MTR-2000 repeaters. Years ago Comm Spec supplied a small board that reset power to the controller to eliminate the problem. We installed power reset modules on all our repeaters, every 24 hours, power is reset to the entire repeater, usually about 3:00 am. CJD --- In Repeater-Builder@yahoogroups.com, Joel ag...@... wrote: We have 2 repeaters that are more or less the same. One is on 2 meters and the other is on 440. They both exhibit the same problem, they lockup after a while and then need to be power cycled. They ran for years without issue. We have the Instruction manual for the Zentron controller, but nothing on the radios. The 440 radios are Motorola M44GM29C3AA's back to back. That's the only model number on the radios. Does anyone have any information on them? A Google search shows 2 Chinese sites having them for sale on e-bay, that's it. Seems strange. Any information would be greatly appriciated, Joe Loucka -- AG4QC
Re: [Repeater-Builder] Re: Antenna Experience Needed!
Keep in mind the bandwidth of the antenna. lh On Wed, Jun 23, 2010 at 9:09 AM, Sid purvis...@yahoo.com wrote: My choice would be the DB-224 type. Sid WA4VBC --- In Repeater-Builder@yahoogroups.comRepeater-Builder%40yahoogroups.com, Chuck Kelsey wb2...@... wrote: My vote would be for folded dipole arrays. Sinclair, Comprod, Telewave and Andrew make good ones. I have seen far too many failures with fiberglass collinear antennas - lighting and particularly internal failure causing untold noise generation to the repeater itself as well as to every radio service nearby. I've never seen a fiberglass one that stood a direct hit but have seen folded dipoles that did. I'd say at least a 3:1 failure rate, maybe higher. That said, any can fail. Chuck WB2EDV We will be mounting 2 meter, 220, and a 440 repeater antennas. 1: What do you recommend between a choice of either RFS or Telewave Superstation Master Type or DB224E Dipole type for top mounting?
Re: [Repeater-Builder] Re: Antenna Experience Needed!
I'm assuming you mean the section of the particular band that a particular model will cover. 'Most' folded dipole arrays and collinear fiberglass manufacturers have models that cover the entire ham band in question, and then some. Chuck WB2EDV - Original Message - From: Larry Horlick To: Repeater-Builder@yahoogroups.com Sent: Wednesday, June 23, 2010 9:17 AM Subject: Re: [Repeater-Builder] Re: Antenna Experience Needed! Keep in mind the bandwidth of the antenna. lh On Wed, Jun 23, 2010 at 9:09 AM, Sid purvis...@yahoo.com wrote: My choice would be the DB-224 type. Sid WA4VBC --- In Repeater-Builder@yahoogroups.com, Chuck Kelsey wb2...@... wrote: My vote would be for folded dipole arrays. Sinclair, Comprod, Telewave and Andrew make good ones. I have seen far too many failures with fiberglass collinear antennas - lighting and particularly internal failure causing untold noise generation to the repeater itself as well as to every radio service nearby. I've never seen a fiberglass one that stood a direct hit but have seen folded dipoles that did. I'd say at least a 3:1 failure rate, maybe higher. That said, any can fail. Chuck WB2EDV We will be mounting 2 meter, 220, and a 440 repeater antennas. 1: What do you recommend between a choice of either RFS or Telewave Superstation Master Type or DB224E Dipole type for top mounting? -- No virus found in this incoming message. Checked by AVG - www.avg.com Version: 9.0.829 / Virus Database: 271.1.1/2957 - Release Date: 06/23/10 02:36:00
Re: [Repeater-Builder] Re: Antenna Experience Needed!
Do you expect to EVER allow other, non-ham users, to multi-couple to this antenna? Plan carefully. If you anticipate to share, then the bandwidth become very important. For example, a Sinclair 210C Series antenna has a 36 mHz, 1.5:1 VSWR bandwidth, essentially covering the whole VHF high band. A Sinclair 222/224 Series has a 10 mHz 1.5:1 VSWR bandwidth. A Sinclair 229 has a 6 mHz, 1.5:1 VSWR bandwidth. UHF follows a similar set of numbers. If you expect to never allow other users on the antenna, then my comments are irrelevant. lh On Wed, Jun 23, 2010 at 9:36 AM, Chuck Kelsey wb2...@roadrunner.com wrote: I'm assuming you mean the section of the particular band that a particular model will cover. 'Most' folded dipole arrays and collinear fiberglass manufacturers have models that cover the entire ham band in question, and then some. Chuck WB2EDV - Original Message - *From:* Larry Horlick llhorl...@gmail.com *To:* Repeater-Builder@yahoogroups.com *Sent:* Wednesday, June 23, 2010 9:17 AM *Subject:* Re: [Repeater-Builder] Re: Antenna Experience Needed! Keep in mind the bandwidth of the antenna. lh On Wed, Jun 23, 2010 at 9:09 AM, Sid purvis...@yahoo.com wrote: My choice would be the DB-224 type. Sid WA4VBC --- In Repeater-Builder@yahoogroups.com, Chuck Kelsey wb2...@... wrote: My vote would be for folded dipole arrays. Sinclair, Comprod, Telewave and Andrew make good ones. I have seen far too many failures with fiberglass collinear antennas - lighting and particularly internal failure causing untold noise generation to the repeater itself as well as to every radio service nearby. I've never seen a fiberglass one that stood a direct hit but have seen folded dipoles that did. I'd say at least a 3:1 failure rate, maybe higher. That said, any can fail. Chuck WB2EDV We will be mounting 2 meter, 220, and a 440 repeater antennas. 1: What do you recommend between a choice of either RFS or Telewave Superstation Master Type or DB224E Dipole type for top mounting? -- No virus found in this incoming message. Checked by AVG - www.avg.com Version: 9.0.829 / Virus Database: 271.1.1/2957 - Release Date: 06/23/10 02:36:00
Re: [Repeater-Builder] Re: Antenna Experience Needed!
Larry is correct. My own personal hope and desire is that there will NOT be other users. Call me greedy, I suppose, but the less RF at the site, the better. However, the guy that posted the original question certainly needs to consider the possibilities. (Sorry, don't remember his name - short memory.) Chuck WB2EDV - Original Message - From: Larry Horlick To: Repeater-Builder@yahoogroups.com Sent: Wednesday, June 23, 2010 10:00 AM Subject: Re: [Repeater-Builder] Re: Antenna Experience Needed! Do you expect to EVER allow other, non-ham users, to multi-couple to this antenna? Plan carefully. If you anticipate to share, then the bandwidth become very important. For example, a Sinclair 210C Series antenna has a 36 mHz, 1.5:1 VSWR bandwidth, essentially covering the whole VHF high band. A Sinclair 222/224 Series has a 10 mHz 1.5:1 VSWR bandwidth. A Sinclair 229 has a 6 mHz, 1.5:1 VSWR bandwidth. UHF follows a similar set of numbers. If you expect to never allow other users on the antenna, then my comments are irrelevant. lh On Wed, Jun 23, 2010 at 9:36 AM, Chuck Kelsey wb2...@roadrunner.com wrote: I'm assuming you mean the section of the particular band that a particular model will cover. 'Most' folded dipole arrays and collinear fiberglass manufacturers have models that cover the entire ham band in question, and then some. Chuck WB2EDV - Original Message - From: Larry Horlick To: Repeater-Builder@yahoogroups.com Sent: Wednesday, June 23, 2010 9:17 AM Subject: Re: [Repeater-Builder] Re: Antenna Experience Needed! Keep in mind the bandwidth of the antenna. lh On Wed, Jun 23, 2010 at 9:09 AM, Sid purvis...@yahoo.com wrote: My choice would be the DB-224 type. Sid WA4VBC --- In Repeater-Builder@yahoogroups.com, Chuck Kelsey wb2...@... wrote: My vote would be for folded dipole arrays. Sinclair, Comprod, Telewave and Andrew make good ones. I have seen far too many failures with fiberglass collinear antennas - lighting and particularly internal failure causing untold noise generation to the repeater itself as well as to every radio service nearby. I've never seen a fiberglass one that stood a direct hit but have seen folded dipoles that did. I'd say at least a 3:1 failure rate, maybe higher. That said, any can fail. Chuck WB2EDV We will be mounting 2 meter, 220, and a 440 repeater antennas. 1: What do you recommend between a choice of either RFS or Telewave Superstation Master Type or DB224E Dipole type for top mounting? -- No virus found in this incoming message. Checked by AVG - www.avg.com Version: 9.0.829 / Virus Database: 271.1.1/2957 - Release Date: 06/23/10 02:36:00 -- No virus found in this incoming message. Checked by AVG - www.avg.com Version: 9.0.829 / Virus Database: 271.1.1/2957 - Release Date: 06/23/10 02:36:00
Re: [Repeater-Builder] Re: Antenna Experience Needed!
Understood Chuck. Depends on the circumstances. I know of a couple of ham groups that have traded antenna space for tower space. The tower owner gave them free space provided he could multi-couple to that antenna. The new systems at the site would be responsible for filtering. It was a win-win and the ham guys paid nothing for a PRIME location. If you own the tower and never plan to expand then it's not an issue. My only reason for bring it up was to encourage everyone to consider all the options and ensure that they will not regret the model chosen. As I am sure you are aware, attaching a big antenna to a high tower is tons of work and not something that any of us would want to repeat unless necessary. lh On Wed, Jun 23, 2010 at 10:08 AM, Chuck Kelsey wb2...@roadrunner.comwrote: Larry is correct. My own personal hope and desire is that there will NOT be other users. Call me greedy, I suppose, but the less RF at the site, the better. However, the guy that posted the original question certainly needs to consider the possibilities. (Sorry, don't remember his name - short memory.) Chuck WB2EDV - Original Message - *From:* Larry Horlick llhorl...@gmail.com *To:* Repeater-Builder@yahoogroups.com *Sent:* Wednesday, June 23, 2010 10:00 AM *Subject:* Re: [Repeater-Builder] Re: Antenna Experience Needed! Do you expect to EVER allow other, non-ham users, to multi-couple to this antenna? Plan carefully. If you anticipate to share, then the bandwidth become very important. For example, a Sinclair 210C Series antenna has a 36 mHz, 1.5:1 VSWR bandwidth, essentially covering the whole VHF high band. A Sinclair 222/224 Series has a 10 mHz 1.5:1 VSWR bandwidth. A Sinclair 229 has a 6 mHz, 1.5:1 VSWR bandwidth. UHF follows a similar set of numbers. If you expect to never allow other users on the antenna, then my comments are irrelevant. lh On Wed, Jun 23, 2010 at 9:36 AM, Chuck Kelsey wb2...@roadrunner.comwrote: I'm assuming you mean the section of the particular band that a particular model will cover. 'Most' folded dipole arrays and collinear fiberglass manufacturers have models that cover the entire ham band in question, and then some. Chuck WB2EDV - Original Message - *From:* Larry Horlick llhorl...@gmail.com *To:* Repeater-Builder@yahoogroups.com *Sent:* Wednesday, June 23, 2010 9:17 AM *Subject:* Re: [Repeater-Builder] Re: Antenna Experience Needed! Keep in mind the bandwidth of the antenna. lh On Wed, Jun 23, 2010 at 9:09 AM, Sid purvis...@yahoo.com wrote: My choice would be the DB-224 type. Sid WA4VBC --- In Repeater-Builder@yahoogroups.com, Chuck Kelsey wb2...@... wrote: My vote would be for folded dipole arrays. Sinclair, Comprod, Telewave and Andrew make good ones. I have seen far too many failures with fiberglass collinear antennas - lighting and particularly internal failure causing untold noise generation to the repeater itself as well as to every radio service nearby. I've never seen a fiberglass one that stood a direct hit but have seen folded dipoles that did. I'd say at least a 3:1 failure rate, maybe higher. That said, any can fail. Chuck WB2EDV We will be mounting 2 meter, 220, and a 440 repeater antennas. 1: What do you recommend between a choice of either RFS or Telewave Superstation Master Type or DB224E Dipole type for top mounting? -- No virus found in this incoming message. Checked by AVG - www.avg.com Version: 9.0.829 / Virus Database: 271.1.1/2957 - Release Date: 06/23/10 02:36:00 -- No virus found in this incoming message. Checked by AVG - www.avg.com Version: 9.0.829 / Virus Database: 271.1.1/2957 - Release Date: 06/23/10 02:36:00
Re: [Repeater-Builder] Re: Antenna Experience Needed!
You bet. My main repeater site is one that I purchased. The only one that can throw me off is my wife. LOL. Chuck WB2EDV - Original Message - From: Larry Horlick To: Repeater-Builder@yahoogroups.com Sent: Wednesday, June 23, 2010 10:24 AM Subject: Re: [Repeater-Builder] Re: Antenna Experience Needed! Understood Chuck. Depends on the circumstances. I know of a couple of ham groups that have traded antenna space for tower space. The tower owner gave them free space provided he could multi-couple to that antenna. The new systems at the site would be responsible for filtering. It was a win-win and the ham guys paid nothing for a PRIME location. If you own the tower and never plan to expand then it's not an issue. My only reason for bring it up was to encourage everyone to consider all the options and ensure that they will not regret the model chosen. As I am sure you are aware, attaching a big antenna to a high tower is tons of work and not something that any of us would want to repeat unless necessary. lh Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * Your email settings: Individual Email | Traditional * To change settings online go to: http://groups.yahoo.com/group/Repeater-Builder/join (Yahoo! ID required) * To change settings via email: repeater-builder-dig...@yahoogroups.com repeater-builder-fullfeatu...@yahoogroups.com * To unsubscribe from this group, send an email to: repeater-builder-unsubscr...@yahoogroups.com * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
[Repeater-Builder] Re: Motorola radios and Zetron 37 (reset timers for frozen controllers)
Re: Motorola radios and Zetron 37 (reset timers for frozen controllers) tracomm trac...@... wrote: This is a regular issue with many controllers, especially Trident Raiders several Comm Spec units, and Motorola MTR-2000 repeaters. I have yet to find any type of relatively complex software driven uP in controller operation that didn't freeze or fart (lock) up at some point in time. One would hope the mfgr hopefully included some type of dead-man or equivalent software-hardware reset timer. Years ago Comm Spec supplied a small board that reset power to the controller to eliminate the problem. For the TP-3200 Tone/DCS Panel... and they were smart/nice enough to provide the timer daughter-board as a free retrofit. We installed power reset modules on all our repeaters, every 24 hours, The Comm Spec supplied timer cycled more frequent. power is reset to the entire repeater, usually about 3:00 am. Is/was there any reason to cycle power to other portions of the repeater hardware? Joel ag4qc@ wrote: We have 2 repeaters that are more or less the same. One is on 2 meters and the other is on 440. They both exhibit the same problem, they lockup after a while and then need to be power cycled. Q: The repeater hardware (radios)? the Zetron Controller? both? Did/do you test to find out what is locked up (not working)? They ran for years without issue. We have the Instruction manual for the Zentron controller, but nothing on the radios. Joe Loucka -- AG4QC You shouldn't need much in the way of manuals to do the basic go, no-go testing. A received signal should indicate on both the RX Radio and the Zetron front panels. The Zetron should indicate valid tone/dcs codes and the Tx activity should be indicated on both the Zetron and TX Radio front panels. Step two depends on the answer(s) to the above question. s.
[Repeater-Builder] Tessco - free shipping promotion
My Tessco account rep emailed me that they're running a promotion this week - free shipping. So if you're thinking about buying a big repeater antenna or a reel of Heliax, save big money on truck freight if you order this week. --- Jeff WN3A
[Repeater-Builder] GE Power Supply 19A149978BP1
Anyone familiar with this beast? It was installed with a MastrII station, but it's putting out 16VDC. It's a newer supply 3RU/Black Front. Looking inside I'm not seeing many options for getting the voltage down. Repeater-Builder.com has a couple of references to the Power Supply in other manuals (EDACS Orion), so I'm guessing this was a replacement that someone stuck in at some point. Anyone who has dealt with one of these, or has a manual? Thanks Chuck n0nhj Glenwood Springs, CO
[Repeater-Builder] Counterfeit ICs
Hello again Sailors,
A friend sent this information to me and I thought it's well
worth passing along. I've removed some of the company name
specific portions.
Re: Counterfeit ICs
[pasted text below]
We had a meeting about this last week. The supply chain folks
were given some pretty strict guidelines on source of supply
and validating real parts.
One of our sister companies uses the xx chip for an XXX amp in
a xxx product. They suddenly had a zero percent pass rate on
temperature cycling...every single IC failed when it was taken down
to cold temperatures...catastrophically...it did not come back to
life. The company's internal sleuths discovered something peculiar
- the date codes on the failed ICs was 2008, but On Semiconductor
says they never built parts with date codes after 2006no new
parts have been made since 2006.
It was via the Sonoscan acoustical imaging technique that they were
able to determine some real differences between the new ICs and
genuine old ICs in the builds from the early 2000sthe ICs were
fake.
The fake IC process itself is fascinating. There is a demand for
old ICs and counterfeiters are more than happy to comply. Old
consumer products go to whatever country, and the solder melted
over a bonfire. Removal of the ICs is done by banging the boards
on the inside of a tin can. ICs are gathered together, and cleaned
in the river to get rid of campfire debris. If the part number is
identifiable, they'll sand off the top printing, spray on a coating
of blacktop, then re-print with a newer date code. In some cases,
they re-plate the leads to make them look new again.
This is if you're lucky - you actually get silicon die inside that
performs the function you want. Sometimes, they're brand-new plastic
packages, but with no functioning IC in them...those counterfeiters
are banking on you putting in an inventory for repair, then not
using them for a long time...then you'll forget who you bought
them from.
The campfire/banging process does damage to the bonding inside the
ICs and makes them fragile. It often introduces microfractures to
the housing, which will allow moisture ingress and the chip will
fail after only a few years.
The supply chain manager of xx company went on a hunt to
determine how these things get into supply. It's almost always
when someone's desperate for a part that's not in production any
more. They ended up giving us a list of known good suppliers who
have solid supply chains. Tyme Electronics, Newark, Future,
Digi-Key and TTI (parent company of Mouser) were all on the
good list. All of them have supplied fake parts, but once
they figured out how they got them, they fixed their systems.
Q components, Quest Electronics, Jameco, Richardson, and RFParts
have refused to acknowledge the problem, and for part numbers in
the catalog which are known to be obsolete, nearly all the
supplied parts measure counterfeit. We're allowed to purchase
from those suppliers, but only after jumping through a lot of
hoops...the part must be in current production, and the supplier
must permit us to inspect their sourcing process and we have to
perform inspections on every delivered lot.
Here's the article that they referred us to for how to identify
fake parts:
http://www.circuitsassembly.com/cms/component/content/article/159/9937?fbc_channel=1#{%22id%22%3A0%2C%22sc%22%3A%22http%3A%2F%2Fwww.facebook.com%2Fxd_receiver_v0.4.php%22%2C%22sf%22%3A%22loginStatus%22%2C%22sr%22%3A2%2C%22h%22%3A%22loginServer%22%2C%
And yes, all of the xxx company's Operating Companies (xx)
that work in electronics have the acoustic imaging system by
Sonoscan.
Here's Sonoscan's original article detailing this hard-to-identify
blacktop that thoroughly emulates the original IC package
(caution - 10 megabyte file, don't download unless you're on a
high speed link)
http://www.smttech.com/pdf/Engineered-Blacktop-Material-Analysis-SMT-Corporation-PP-08-27-09.pdf
A more brief article on the new blacktopping material:
http://www.idofea.org/new_site/index.php?option=com_contentview=articleid=97:new-counterfeiting-blacktopping-technique-threat-is-a-qc-game-changercatid=29:generalinfoItemid=3
A more general article on how to identify counterfeit parts
(including an X-ray photo of a package that had no die in it):
http://www.empf.org/empfasis/2007/Nov07/tech_tipsr-1107.html
When dissected, what they found is that the die attach
inside the package was severely compromised, with only 25% of the
die actually thermally in contact with the package. With enough
heating/cooling cycles and/or vibration, these chips were destined
to fail prematurely even without thermal cycling. The thermal
cycle simply allowed their earlier discovery.
Other interesting things that have been found: so-called new old
stock parts with more legitimate date codes - that were still
counterfeit.
They also cautioned you
[Repeater-Builder] Quantar Simulcast Issue
I'm looking for some Quantar engineering level help re: an interesting simulcast issue. I live in an area where I can hear several of high band our simulcast Quantars. The whole thing was installed and set up by Motorola including GPS stabilized time bases. I'm monitoring with a true monitor: wide band IF and little limiting. When the dispatcher drops a dead carrier I hear little in the way of hetrodyne or grunge as it should be. However, when the dispatcher drops alert tones I hear a hetrodyne that decreases in frequency over the duration of the tone. My guess is that the tone is somehow pulling one of the VCOs in a Quantar exciter because of a lack of DC restoration in the modulator: a capacitor is charging and slightly shifting frequency. I consider this to be abnormal and undesirable behavior - especially in a $y$tem of thi$ caliber. I haven't done any field tests yet. I suppose I can set up 2 service monitors: one to receive in the AM mode and the other to provide a reference carrier and then send tone to each transmitter, in turn. That, at least would let me isolate the problem to one, two, ?? radios. Has anyone else experienced a problem like this? Any Motorola engineers out there? Our local tech is also baffled so I'm reaching out for ideas. Thanks, Bill Powell
Re: [Repeater-Builder] Quantar Simulcast Issue
Are the cables coming from the GPS reference are the same length at both sites? Also if these are VHF it could be that the reference frequency (channel spacing) is 5 kHz, if that is the case a harmonic of a paging tone might get past the audio pass band filtering 300 - 3000 Hz typically and is fooling the PLL divider. On Wed, Jun 23, 2010 at 1:01 PM, wmhpowell w...@att.net wrote: I'm looking for some Quantar engineering level help re: an interesting simulcast issue. I live in an area where I can hear several of high band our simulcast Quantars. The whole thing was installed and set up by Motorola including GPS stabilized time bases. I'm monitoring with a true monitor: wide band IF and little limiting. When the dispatcher drops a dead carrier I hear little in the way of hetrodyne or grunge as it should be. However, when the dispatcher drops alert tones I hear a hetrodyne that decreases in frequency over the duration of the tone. My guess is that the tone is somehow pulling one of the VCOs in a Quantar exciter because of a lack of DC restoration in the modulator: a capacitor is charging and slightly shifting frequency. I consider this to be abnormal and undesirable behavior - especially in a $y$tem of thi$ caliber. I haven't done any field tests yet. I suppose I can set up 2 service monitors: one to receive in the AM mode and the other to provide a reference carrier and then send tone to each transmitter, in turn. That, at least would let me isolate the problem to one, two, ?? radios. Has anyone else experienced a problem like this? Any Motorola engineers out there? Our local tech is also baffled so I'm reaching out for ideas. Thanks, Bill Powell Yahoo! Groups Links
[Repeater-Builder] Re: Quantar Simulcast Issue
wmhpowell w...@... wrote: I'm looking for some Quantar engineering level help re: an interesting simulcast issue. Does it have to be Quantar? I live in an area where I can hear several of high band our simulcast Quantars. The whole thing was installed and set up by Motorola including GPS stabilized time bases. All that and $3 can sometimes get you a decent latte. I'm monitoring with a true monitor: wide band IF and little limiting. When the dispatcher drops a dead carrier I hear little in the way of hetrodyne or grunge as it should be. Hopefully meaning the carriers are close to each other and not moving around a lot. However, when the dispatcher drops alert tones I hear a hetrodyne that decreases in frequency over the duration of the tone. During the tones present or after the tones go away? My guess is that the tone is somehow pulling one of the VCOs in a Quantar exciter because of a lack of DC restoration in the modulator: a capacitor is charging and slightly shifting frequency. Why would you guess that? I consider this to be abnormal and undesirable behavior - especially in a system of this caliber. How about any Simulcast System... I haven't done any field tests yet. I suppose I can set up 2 service monitors: one to receive in the AM mode and the other to provide a reference carrier and then send tone to each transmitter, in turn. That, at least would let me isolate the problem to one, two, ?? radios. Not where I'd first go/test... Has anyone else experienced a problem like this? Yes Any Motorola engineers out there? Can I be an Authorized Kenwood Service Station and Dealer Instead? Or is a retired from Motorhead Field Service person OK? Our local tech is also baffled so I'm reaching out for ideas. Thanks, Bill Powell Keyboard player for Lynyrd Skynyrd? Getting serious for a hopefully brief moment... How is the tx audio making it's way to the repeater/base stations? Have you checked and compensated for group delay on those paths? Got milk? s.
RE: [Repeater-Builder] Quantar Simulcast Issue
Are the cables coming from the GPS reference are the same length at both sites? Maybe I'm missing something here, but how the heck would the length of the cable from the reference oscillator to the transmitter/exciter matter? It's just the frequency reference (10 MHz or whatever) for the synthesizer; it has no effect on delay, phase, amplitude response, or anything else related to the modulated audio. Also if these are VHF it could be that the reference frequency (channel spacing) is 5 kHz, if that is the case a harmonic of a paging tone might get past the audio pass band filtering 300 - 3000 Hz typically and is fooling the PLL divider. This seems like a longshot. I think Bill's original guess is most likely on the right track - a DC offset problem. I'm assuming the transmitters are being modulated through a non-DC-coupled input to the modulator? Maybe look for a coupling cap with high leakage. Another thought is asymmetrical clipping of the audio. --- Jeff WN3A
Re: [Repeater-Builder] Quantar Simulcast Issue
Propagation delay in the coax. Get a dual trace oscilloscope and feed it with a 10 MHz GPS, off of a Tee and into 2 different lengths of coax. I could see the DC offset thing if the audio was coupled with a 1uF cap at one site and a 0.1uF at the other. Maybe I'm missing something here, but how the heck would the length of the cable from the reference oscillator to the transmitter/exciter matter? It's just the frequency reference (10 MHz or whatever) for the synthesizer; it has no effect on delay, phase, amplitude response, or anything else related to the modulated audio. Also if these are VHF it could be that the reference frequency (channel spacing) is 5 kHz, if that is the case a harmonic of a paging tone might get past the audio pass band filtering 300 - 3000 Hz typically and is fooling the PLL divider. This seems like a longshot. I think Bill's original guess is most likely on the right track - a DC offset problem. I'm assuming the transmitters are being modulated through a non-DC-coupled input to the modulator? Maybe look for a coupling cap with high leakage. Another thought is asymmetrical clipping of the audio. --- Jeff WN3A Yahoo! Groups Links
Re: [Repeater-Builder] Quantar Simulcast Issue
wmhpowell wrote: I'm looking for some Quantar engineering level help re: an interesting simulcast issue. I live in an area where I can hear several of high band our simulcast Quantars. The whole thing was installed and set up by Motorola including GPS stabilized time bases. I'm monitoring with a true monitor: wide band IF and little limiting. When the dispatcher drops a dead carrier I hear little in the way of hetrodyne or grunge as it should be. That means that the transmitters are on the same frequency... that's good. Do they start out this way, or do they start out a little off and then settle to perfectly quiet? Systems which don't keep the transmit oscillator running can have the former effect. However, when the dispatcher drops alert tones I hear a hetrodyne that decreases in frequency over the duration of the tone. What's the frequency of the hetrodyne? Subaudible flutter? Audible beat note? If this was an audible artifact that only was really noticeable with pure tones, I'd suggest that the audio phasing isn't set up correctly... but since it changes over the duration of a single tone, it is more likely something pulling the frequency of one or more of the transmitters rather than audio phase. My guess is that the tone is somehow pulling one of the VCOs in a Quantar exciter because of a lack of DC restoration in the modulator: a capacitor is charging and slightly shifting frequency. That's a good guess, as is the other guess posted that one of the PLLs is coming unlocked due to a harmonic of the modulating tone. Another possibility: are you using tone remote keying? Perhaps the keying tone is leaking through to one of them and unlocking its PLL briefly and then you're hearing it come back into lock. I consider this to be abnormal and undesirable behavior - especially in a $y$tem of thi$ caliber. Agreed, but you're 99% of the way there it sounds like, so a minor problem in the scheme of what can go wrong with simulcast. I haven't done any field tests yet. I suppose I can set up 2 service monitors: one to receive in the AM mode and the other to provide a reference carrier and then send tone to each transmitter, in turn. That, at least would let me isolate the problem to one, two, ?? radios. If you can key one at a time with the tone, you should be able to see if the transmit frequency wanders on one of them differently than it does on the others. If you don't have a monitor that is sufficient to measure the error, then yes, using a second service monitor as a low-power generator to heterodyne against is a good idea. But you'll want to receive in FM mode. Has anyone else experienced a problem like this? I haven't... usually I hear systems that simply start off frequency when they key and take a fraction of a second for everything to be on-frequency. In the system I built for my ham repeaters, I run the transmit PLL 100% of the time for just this reason. Matthew Kaufman
Re: [Repeater-Builder] Quantar Simulcast Issue
DCFluX wrote: Are the cables coming from the GPS reference are the same length at both sites? This wouldn't matter at all. For frequency, it has no effect, and if the GPS 1pps is being used for audio phase this would just offset the phase as though the transmitter itself were moved by the same number of feet (and/or its feedline increased by that amount)... not audible at all, as audible artifacts only start after a few *miles* of phase error. Also if these are VHF it could be that the reference frequency (channel spacing) is 5 kHz, if that is the case a harmonic of a paging tone might get past the audio pass band filtering 300 - 3000 Hz typically and is fooling the PLL divider. I like this guess,... that the paging tone (or tone remote keying, as I suggested a moment ago) is causing one to come unlocked. Matthew Kaufman
[Repeater-Builder] Re: Quantar Simulcast Issue
--- In Repeater-Builder@yahoogroups.com, wmhpowell w...@... wrote: I'm looking for some Quantar engineering level help re: an interesting simulcast issue. ... Thanks, Bill Powell -- When you say this system was set up and installed by Motorola - does that mean a 'factory direct' Motorola project or a local dealer? Is the baffled tech a shop tech or a Motorola employee [e.g. S.T.]? You say the system is GPS stabilized - do you mean what Motorola refers to as GPS Simulcast? If so, the transmit path would originate at a prime site where voted receive and/or dispatch transmit audio would be routed to a CSCI or USCI, then to an SDA, then to a Premysis TeNSr channel bank into DSM-II cards, then over T-1 paths to each remote site where channel banks with corresponding DSM cards connect to the wideband simulcast Quantar tx inputs. The GPS reference clocks, typically from Trak, provide 5 MHz reference to the Quantar stations and 1PPS timing to the DSM's which automatically time align the transmit audio. This is a proven working product. The hypothesis regarding lack of DC restoration in the modulator would suggest a design issue which is highly unlikely given the number of succcessfully fielded Quantar simulcast systems. If you are going to investigate this issue you should begin with the most current version of the Motorola GPS Simulcast manual: 6881098E65. On the other hand, it this system was implemented by a local dealer using some other form of simulcast distribution such as Harris SynchoCast - there could be any number of issues. In any case - proper Quantar programming, netting, and Mod-comp adjustment are critical. Audio phasing and level optimization is best verified using a DSA [Dynamic Signal Analyzer] such as the Agilent 35670A.
RE: [Repeater-Builder] Quantar Simulcast Issue
Propagation delay in the coax. Propagation delay doesn't affect anything on the reference output side of the GPSDO. The phase of the reference oscillator can vary -- the synthesizer doesn't care about the phase of the reference oscillator, only the frequency. Likewise, the VCO output isn't synchronized in any way to the reference oscillator as far as phase goes. Get a dual trace oscilloscope and feed it with a 10 MHz GPS, off of a Tee and into 2 different lengths of coax. Well, yeah, I know what propagation delay is, but I don't see where the phase of the reference has an effect on anything. Are you thinking that the transmitter's RF carrier needs to be launched with phase coherence at each site? --- Jeff WN3A
Re: [Repeater-Builder] Quantar Simulcast Issue
Well if the transmitters are running at the same frequency but at a different phase it is reasonable to expect that there would be some point where the 2 transmitters are at close to the same power level, but 180 degrees out of phase which should cancel out the receiver or at least make interesting noises. Well, yeah, I know what propagation delay is, but I don't see where the phase of the reference has an effect on anything. Are you thinking that the transmitter's RF carrier needs to be launched with phase coherence at each site? --- Jeff WN3A Yahoo! Groups Links
Re: [Repeater-Builder] Quantar Simulcast Issue
DCFluX wrote: Well if the transmitters are running at the same frequency but at a different phase it is reasonable to expect that there would be some point where the 2 transmitters are at close to the same power level, but 180 degrees out of phase which should cancel out the receiver or at least make interesting noises. Yes, but this effect doesn't cause the reported problem. Matthew Kaufman
