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eHam Forums / Amplifiers / RE: Ameritron AL-82 Loud Bang
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on: March 17, 2013, 03:00:13 PM
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Tor: Did you notice ANY kind of indication that this poor solder joint/connection was arcing? I'm having a difficult time getting my head wrapped around your "solution."
No- I know the arc was somewhere in the power supply because I could see the flash through the left vent holes. But I never ran the amp without the cover off so I could not pinpoint exactly where it was coming from. Tor N4OGW |
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18
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eHam Forums / Amplifiers / RE: Ameritron AL-82 Loud Bang
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on: March 16, 2013, 07:34:01 PM
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Rule of thumb with MFJ equipment , ALWAYS inspect and repair the common cold/bad/no solder joints prior to plugging in , even if it is new and right out of the box.
No, this one was my fault! I had to unsolder/resolder the connections to the HV filter board when I replaced the caps. Tor N4OGW |
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19
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eHam Forums / Amplifiers / RE: Ameritron AL-82 Loud Bang
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on: March 15, 2013, 09:56:19 AM
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Bill: I hope you have indeed found your problem. If it was a sheet metal "bang" then there is one thing left to do.
When you reassemble the cabinet, etc., make sure there isn't any binding or pulling by the screws. As long as it goes together without any stress, the problem shouldn't reappear.
Yup will do. Lets hope it was as simple as that. Boy it really must have a flex point somewhere because it's pretty loud. But definitely no arc that I can see. I ran it tonight without any problems, cover tomorrow. Tor, sounds like yours is much different than mine, a lightning bolt like that will surely get you attention. Hope you can find where it's coming from. I think I found the problem. After checking the HV supply carefully the only potential problem I could see was a solder joint on one of the HV leads going to the filter capacitor board. It is a stranded wire and the connection didn't quite have enough solder. I fixed that and it started up without arcing. Tor N4OGW |
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20
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eHam Forums / Amplifiers / RE: Ameritron AL-82 Loud Bang
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on: March 08, 2013, 02:19:38 PM
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I'm not sure if they are "short" or "long". They were exactly the same size as the ones I took out. There is plenty of space between them and the chassis in the AL-1500, so I doubt that is the problem. It is not a minor arc, the first time it went off I almost fell over in my chair  I need to check again carefully to see if I can see evidence of where it arced. Tor N4OGW |
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21
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eHam Forums / Amplifiers / RE: Ameritron AL-82 Loud Bang
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on: March 08, 2013, 12:50:30 PM
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It should be easy to tell the difference between sheet metal and a HV arc- they usually sound rather different. I am curious what you find because I am having a similar problem with my AL1500: After about 10 years service, one of the HV caps failed: there was a bang and the fuse blew. When I checked the capacitors, it was obvious one had vented. I replaced all the caps and bleeder resistors. After the cap replacement it ran fine for a couple of months. Then completely at random there was another arc somewhere in the HV supply. I did see a flash through the vent holes on the left side of the amp, but with the cover on I couldn't locate the exact spot. Very loud, definitely not a sheet metal noise. This time the fuse didn't blow, but the protection circuit took the HV off line. I took it apart again, but couldn't find any obviously damaged capacitor or bleeder resistor. I also discovered the arc had destroyed one transistor in the QSK circuit. I replaced that and put everything back together. As soon as the HV turn on, another big bang  So now I need to take it apart again. Maybe I have a wire out of place that created the arc. One clue is that when it arcs the fuse does not blow like it did when one of the caps failed. But testing is difficult, because every arc takes out more components in the QSK board! Tor N4OGW |
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22
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eHam Forums / DXing / RE: Earning Honor Roll Using Others Stations
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on: March 01, 2013, 06:58:31 PM
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You are quite right... the dropping of that requirement has certainly added a lot of confusion; especially when trying to figure out where the spotting station on a cluster is actually located! Just because they have an 8 call, surely doesn't mean they are in OH, MI, or WV!! No more confusing than trying to figure out if the W8 spotter is in the easternmost tip of West Virginia (practically a W3) or the western most tip of Michigan's Upper Peninsula (practically a W0!) :-) Or a W5 just over the border from AL compared to a W5 just over the border from AZ...more than 1000 miles apart! Tor N4OGW (/5) |
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23
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eHam Forums / Amplifiers / RE: Second harmonic when operating 160m
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on: February 22, 2013, 10:47:13 AM
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But it would be an awkward Z on 10 MHz.
Yes! I have stubs on many of my antennas because I do SO2R during contests. It does unfortunately make it very hard to use antennas on multiple bands. Tor N4OGW |
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25
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eHam Forums / Elmers / RE: Strange Propagation
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on: February 20, 2013, 09:41:35 AM
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Thanks for the input.
I don't understand why Kentucky was stronger pointing at me versus south and my strongest angle to him was 180 south and anything off that was either much weaker or lost completely?
Read what I wrote above again: the propagation was long path, which is east of KY. When he was pointing south, he had you in the null off the side of his yagi. When he pointed west, he had you off the back of his yagi and his signal came up. If he had pointed it towards the east he would have been even stronger. This is typical for most yagis- the deepest null is off the side of the antenna, not the back. Tor N4OGW |
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26
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eHam Forums / Elmers / RE: Strange Propagation
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on: February 19, 2013, 02:35:51 PM
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This sounds just like usual long-path propagation to me. It is not that unusual for beam headings to be a little different for very long paths. Something I haven't seen before...
This morning about 2.5 hours after sunrise.. AE4QK in Kentucky was about 5/1 pointing S from my QTH in Hawaii - barely readable SP to the N/E.
He had a call in CA and moved his antenna from FL he said to CA direction. That increased his audio noticeably and was about a 5-3 - very clear. So I thought.. I'll turn my antenna N/E for SP and I'll hear him better.. Nope.. it was worse - readable but very weak.
From his qth, the long path heading is about due east. If he had his beam towards FL, you would actually be off the side of his beam. When he pointed it west, you were off the back. Most beams have a deeper null towards the side, so when he moved that away from you his signal came up.
So when he pointed in my direction I could hear him better but I needed to keep my antenna pointing towards the South for the best reception??
(In the past - usually when the East Coast turns their antenna towards me - I lose them. This was different. Usually the best signal was when they pointed East or South East.)
Was today just strange propagation...?
About 1 hour after sunrise I had EA3JR in Spain who was 5/1 on a dipole with 100W and I was 5/7 to 5/8 pointing South with Hex Beam and about 600W.
I'm glad to have a path.. I'm just trying to understand it.
Currently I say.. "Long Skewed Path".. Possible Greyline assistance?
Your hex has a very wide pattern so it will be really hard distinguish between a signal coming from S or SW headings. Plus with your antenna close to a roof and with other antennas nearby the pattern could be somewhat distorted. Do you have a balun on it? Without a balun the pattern there could be further distortions of the pattern. You might be able to get a more accurate heading to a station by pointing the NULL of your beam towards the other station and turning it until you get the minimum signal. Tor N4OGW |
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27
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eHam Forums / DXing / RE: EP3SMH
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on: February 18, 2013, 01:03:58 PM
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I received a qsl from SMH in 2009, I sent direct with maybe $2?
Note that the inflation rate in Iran is very high, something like 25% recently.
Tor
N4OGW
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29
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eHam Forums / Station Building / RE: Array Solutions Power Master II vs. Telepost LP-100A
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on: February 05, 2013, 11:16:43 AM
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I've owned a Bird 43 wattmeter for years, and have decided to purchase either an Array Solutions Power Master II or the Telepost LP-100A.
Any comments, as to "Pros" and "Cons" of each. It appears that both are very accurate traceable to NIST standards, but am looking for user comments as to user-friendliness, reliability, the included software for interfacing to a PC, customer support, etc. - i.e. overall satisfaction.
Tnx,
Don W9CW
I have a LP100 and like it a lot. A great feature of the LP100 I think the others don't have is the ability to calculate impedance. That was very useful when I was shunt-feeding my tower on 160...my antenna analyzer was useless because of BC interference. Tor N4OGW |
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30
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eHam Forums / HomeBrew / RE: Surface mount anyone?
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on: January 31, 2013, 10:54:35 AM
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I recently built a SDR-Widget kit here (see http://www.yoyodyneconsulting.ca/pages/SDR-Widget.html). Soldering the LQFP144_20 CPU was a challenge! With this kind of part it is basically impossible to solder to individual pins. But it can be done using just a good soldering iron, solder, and solder wick. Basically: 1) tack the chip down on two sides. Getting the pin alignment perfect is what matters, don't worry about bridging pins. 2) run solder down each rows of pins- get plenty on, again don't worry about solder bridges. it will look terrible after this step. 3) suck off all the excess solder with solder wick. Just the right amount of solder will remain on each pin! There are some videos at Sparkfun explaining this technique. It is great if you just have a few parts and don't want to build/buy stuff for reflow soldering. Tor N4OGW |
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