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Re: Equipping an Electronics Lab on the Cheap by Ed Nisley KE4ZNU
¿ªÔÆÌåÓý(Laugh) I know what you mean.? Most of my customers didn't care, as long as they couldn't be held liable or would have to pay out of pocket.? I was just a service provider, not an employee so I really didn't count.? Something happened to me... unless they could be sued, it might mean not having to pay for the work. I could tell all sorts of horror stories about places I went in,
but that's not even close to topic. (Regarding test equipment... I miss the
scope that got fried.? Relatively portable, fairly wide analog
bandwidth and dual trace, and had a built-in multimeter.?
Purchased used/surplus and it was reliable up until that day.? I
think it was an HP... and I've found that HP and Tek boat anchors
to be pretty reliable, as long as you kept them cool.)
On 5/6/19 12:57 PM, Robert Alexander
wrote:
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Re: Equipping an Electronics Lab on the Cheap by Ed Nisley KE4ZNU
I worked for a company that didn't care much for lock out tag out procedures until one guy almost got killed. Management changed their attitude pretty quick then. Robert Alexander From my iPhone 8
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Re: Kit-Projects ND6T Ubitx AGC
That actually has a much more appropriate response curve! I feel like the issue now is more related to signal density then anything else. As in with that 10¦¸ Resistor we are finally getting an appropriate response :) How does it perform as an AGC in that wireup? I guess that is the "real" test anyway. -- Tim Keller - KE2GKB |
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Re: Equipping an Electronics Lab on the Cheap by Ed Nisley KE4ZNU
¿ªÔÆÌåÓýI didn't have a lock... and the company didn't provide one -
considered a tag to be sufficient.? That was back in the late 80s,
as I remember.? Tagging and locking were considered "Government
regulations harming my business!!!" by a lot of companies in this
area.? It sometimes caused friction. BTW... it's offensive to add insult to injury.? It was THEIR responsibility, or their employees, to respect the tag... not my 'fault' because one was too stupid to think or read.
On 5/6/19 12:22 PM, Robert Alexander
wrote:
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Re: Equipping an Electronics Lab on the Cheap by Ed Nisley KE4ZNU
That is why you lock out and not just tag it. Robert Alexander From my iPhone 8
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Re: Equipping an Electronics Lab on the Cheap by Ed Nisley KE4ZNU
¿ªÔÆÌåÓýThe Radio Shack unit I had (the only meter I ever destroyed - by
the output of a 50hp PWM servo drive that had too much of an AC
component on a DC voltage) was really rugged (I replaced it with
the same model).? When the thing blew, it popped internal fuses
and shut down the drive, and the only thing that happened was
smoke coming out of the lead holes.? Needless to say, I was one
unhappy camper about that. The better units often come with a plastic (insulative) cover or sleeve which helps to contain things like that - they're always a good idea to have on.? (Flukes are pricey but awesome units, I could never afford the model I liked, which had a computer interface.)? I think that sleeve helped to contain the 'pop' (It was quite... audible). Talking about having equipment blown up... I did have a scope blown up one time - working on a CNC machine and was doing some special tests in the control.? Stupid nut of an employee pulled the tag from the breaker and flipped it on - sparks and smoke everywhere (fried what was left of their control too).? The company refused to do anything to the stupid jerk, and refused to replace the (portable) Tek scope he destroyed - he almost fried me too (I did get a small burn on my shirt from a spark).? His argument "I need to punch some holes NOW!!!" - even though the machine was NOP and tagged out.? That was the last time I went in that plant. (The company said because nobody else saw it, that they wouldn't do anything about it, it was my word against their employee!? They also implied that they were going to charge me for a replacement control - even though the jerk did say out loud in the presence of others "but I had to punch some holes!!!")
On 5/6/19 9:00 AM, Jim wrote:
One thing to keep in mind with a DVM is it¡¯s safety rating. Should a transient voltage hit the meter you want the meter to be able to interrupt the internal fault and protect the user with adequate insulation in the probes, leads, and case. At minimum you should look for a Cat 1 rating. Here is some info from Fluke>> |
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Locked
Re: bad news and a bit of good news.
¿ªÔÆÌåÓýThat hurts (I've been there)!? I lost all of my equipment (except
for one radio and some parts) back in 2010, when someone got angry
at a letter to the editor I'd written and torched my electronics
workshop/home laboratory.? (I'm still working on recovering.)?
I've also had vehicles destroyed in accidents, and because of the
county (never informed me of the court date when a woman hit me
head-on while driving in the wrong lane - she got the ticket for
it but it was all dropped "because you didn't show!!!") took a
total loss on the vehicle.? (A clue about my driving skill and
history - over 1.2 million miles driven with no at-fault accidents
in the last 35 years.) I hope you can find the resources to get back on your feet very
soon.? The longer you have to wait, the more it hurts. Good luck!? I'm hoping the best for you - and that the impact to your life becomes minimal! Bob N4FBZ On 5/4/19 4:52 PM, Wayne Leake wrote:
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Re: Equipping an Electronics Lab on the Cheap by Ed Nisley KE4ZNU
I agree with Jerry -- the Harbor Fright DVMs are the ones I reach for first.? ? Like Jerry, I do that because they are cheap crap and I don't care if I blow one up.? Having set fire to the same Fluke 77 three times, I agree, blow up the cheap junk first.? I will mention that Fluke has always been more than generous on repair or upgrade replacement on my 77s.? So they're high on my "use vendor again" list.? I'll also add -- the ME-77C/U mil-surplus multimeter (google iot) is on my "maybe you don't want to buy this again, because it uses a $75 unobtainium 22.5 V battery that can't be replicated from current sources.? But if I could get one to work ... I'd put it out on my Field Day table for testing stuff.? And then I'd get a few more. Why?? Because everybody around here (Austin TX, within shouting distance of all the airbases in San Antonio) we see a lot of these in the junk boxes at swap fests, and they're kinda the 1950s version of the crap Harbor Fright DVMs.? Most of the gentlemen who used to use these have passed, but there are a few of us who still recognize classic utility. |
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Locked
Re: bad news and a bit of good news.
Wayne this really is bad news.? Were you able to save anything else?
-- |
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Re: Equipping an Electronics Lab on the Cheap by Ed Nisley KE4ZNU
¿ªÔÆÌåÓýOne thing to keep in mind with a DVM is it¡¯s safety rating. Should a transient voltage hit the meter you want the meter to be able to interrupt the internal fault and protect the user with adequate insulation in the probes, leads, and case. At minimum you should look for a Cat 1 rating. Here is some info from Fluke>>On May 6, 2019, at 1:22 AM, Wayne Leake <wayneleake@...> wrote:
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Re: Equipping an Electronics Lab on the Cheap by Ed Nisley KE4ZNU
?I have several low priced DVM's. ?Only damaged one so far, wrong kind of voltage, like the electric fence, Dern. ?I have a slightly better one from Tractor supply, that has a few extras, such as capacitance, and an outboard item for transistors. ?Also has a stand of sorts to prop it up, and came with clips to use on the probes. ?Be great if it could test what is left of my truck. ?Burned up Friday evening, just after I got home. ?needing help to buy another. ?I have bought a lot of things from HF, though now I buy stuff from Tractor supply, as it is more convenient. ?Wayne WA2YNE ?In need of a decent pickup now. |
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On May 5, 2019, at 4:18 PM, vk6qa <vk6qa@...> wrote:
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Hi everybody,
? ? // If we have received Mode data, then we're good to go
? ? if (radio.mode)
? ? {
? ? ? trx_set_am_mode(); ? ? ? ? ? ? ?// AM mode
? ? ? delayloop(50);
? ? ? if (radio.pwr_available) trx_set_min_pwr(); ?// Set Minimal power
? ? ? delayloop(50);
? ? ? trx_set_tx(); ? ? ? ? ? ? ? ? ? // TX mode
? ? ? delayloop(250); ? ? ? ? ? ? ? ? // Give time for Power to come up
? ? ? measure_power_and_swr(); ? ? ? ?// Ensure we have one measurement available
? ? ? progress = SUCCESS; ? ? ? ? ? ? // Setup for Autotune is initiated ?
? ? }
? ?
? ? // Timer has expired without receiving response from radio - FAIL
? ? else if (timer == 0)
? ? {
? ? ? progress = FAIL;
? ? }
? }
? return progress;
}
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¿ªÔÆÌåÓýHi Nick ? Did you consider placing a RX pre amp on your new board? ? Keith Perry VK6QA From: [email protected] [mailto:[email protected]] On Behalf Of Nick VK4PP
Sent: Thursday, 2 May 2019 6:00 AM To: [email protected] Subject: Re: [BITX20] VK4PP Ultimate uBitx Daughter Board. #ubitx #filters #parts ? HI All. |
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Re: Equipping an Electronics Lab on the Cheap by Ed Nisley KE4ZNU
I've got about 10 of the HF dvm's lying about,
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I do have better, but the HF are generally the first dvm I reach for. Mostly because there is likely to be one close at hand. I've never found accuracy to be an issue, they are extremely accurate. A capacitance range would be nice, and auto ranging can be handy too. Probe wires separate from the probes after a few months of hard use, easy to fix. My primary issue is the HF dvm's seem easier to destroy than some of the other dvm's, doing stupid stuff like having the dvm set to ohms when looking at a voltage source.? Especially when??probing stuff out in the rain at night when the pickup has an electrical failure or something.? And in that case it would always be the HF, since I have one in the glovebox. When I do pop one, it's a very cheap $1.00 (on sale) lesson. Not a $100 one. Good idea to color the business end of the knob so you don't accidentally? have it turned 180 degrees from what you want. Jerry, KE7ER ?? On Sun, May 5, 2019 at 07:23 AM, Doug W wrote:
I disagree with his hate for cheap/free Harbor Freight multimeters.? Sure they're not nuclear grade accurate but for a ham on a budget they have their place.? Besides, it is most likely more accurate than the tolerances of the components being tested. |
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Re: Kit-Projects ND6T Ubitx AGC
Mark,
I'm hardly an expert at what I'm doing so, I can't be too far ahead of you. With your signal generator and voltmeter you ought to be able to make the same measurements I have. Give us some idea of what first baby steps need help with. I don't know the HP8640b but I can try to help with where to connect and take measurements. -- digger AB3XU? |
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Re: Kit-Projects ND6T Ubitx AGC
Tim,
Had a chance last night to make some more measurements. Hopefully we are the same page now. I made two sets of measurements to look at the difference between taking the audio on the ubitx on either side of R70 -- vol-h and TP21. Also curious I made them with USB and LSB. So..... Sark 110 (7.101Mhz) --> ubitx (7.099.7 USB) ???? vol-h --> AGC, vol-h ???? TP21 --> 11.4ohm --> AGC, vol-h Sark 110 (7.100Mhz) --> ubitx (7.100.7 LSB) ???? vol-h --> AGC, vol-h ???? TP21 --> 11.4ohm --> AGC, vol-h That tuning on the ubitx gets a tone very close to 1K. (i guess that means I need to adjust the BFO by about 300Hz) The resister is 11.4 ohms - my other choice was 9ohms. AGC was in the middle/slow position. The measurements I'm getting with using TP21 for the input to the AGC still seem lower by about half than what is expected based on ND6T's circuit theory and numbers he posted in another thread. ADC Comparison of ND6T's numbers and my readings from CEC firmware RF???????? ND6T??? mine S9?????????? 170???????? 84 S9+10??? ?? -????????? 170 S9+20???? 300??????? 200 S9+30?????? -?????????? 297 S9+40???? 700??????? 399 S9+50???? 800??????? 517 I hope this all makes sense! Let me know if anything need interpretation! I would really like to see some measurements made with another V4. |
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Re: Low power output on ubitx
what is version # please? On Sun, May 5, 2019 at 7:50 PM sdr freak <sdrfreak55@...> wrote: Hi Mike,? |
Jim
digger AB3XU
