Sorry, I meant to also say that you can see that the trace noise is a bit more jaggy below about 3MHz and this is probably to be expected as the noise source ENR is starting to fall and the noise floor of the analyser is degrading by at least 1dB at the lower end of the frequency range. This is causing the gain and noise figure traces to look more jaggy. Averaging would hide this to some degree but I left it running without averaging to demonstrate this. So the system is struggling a bit more here.
|
Locked
Re: Fees due soon for the group - please sponsor it.
Did you turn sponsorship back on yet?
When I tried to follow the link, it just redirected back to the main page for the group, and the word 'sponsor' doesn't appear anywhere on that page. On Thu, Oct 17, 2024 at 5:31?AM Dr. David Kirkby, Kirkby Microwave Ltd via <drkirkby= [email protected]> wrote:
The fee ($110) for the group are due at the end of the month, so I'd like to request that you consider sponsoring the group. Last time I asked this, the amount of money collected in a short time far exceeded what was needed. I'm reluctant to let a lot of money build up, since it's non refundable, so I disabled the ability to sponsor the group.?Quite a few people were disappointment that they could not contribute.
?
Could I suggest that
?
1) You only donate $5.
2) You don't donate if you have already done so before.
?
That will need just 22 people to donate. If after a couple of days there's not enough money, I'll ask people to add a bit more, but based on previous experience, the amount needed will soon be reached.
?
Also, please do not send money to my email address by PayPal - this is a business email address, and it would cause me problems.
?
So if you have not donated before, click this link to donate $5.
?
?
Dave
|
Yes, I think the AWGN technique gets used a lot, both with real hardware and with simulations (eg Matlab or Octave etc).
?
I had a go at measuring the BFR91 preamp section on an old 26.5GHz Agilent PSA analyser today (with my HP 346A noise source) and it did a pretty good job across 2MHz to 20MHz, even with the internal HPAK preamp.? This is the only analyser I know of that has a chance of getting good results across this frequency range when using a 346A noise source with its low ENR of about 5dB. I think this particular analyser has an improved preamp in it compared to earlier models. However, the internal preamp only works up to about 3GHz. It offers a noise floor of about -170dBm/Hz down to a few MHz and I think it degrades to about -168dBm/Hz by about 1MHz. This is much better than any other HPAK analyser model that I know of. The input VSWR is quite good too at these frequencies.
?
I haven't used any averaging for either the cal or the measurement and it has given a fairly flat result as expected. I don't actually know what the correct noise figure is for this preamp. The simulation predicted a flat 3.6dB noise figure to below 1MHz but it usually gives a result that is slightly low.
?
I had to tweak my original ENR table at 2MHz to get a flat result at 2MHz though. I reduced it by 0.6dB. I also reduced the 3MHz entry by?about 0.3dB. This is in line with my earlier noise floor measurements using the RSA3408A. This gave a very pleasing result!
?
However, I'll try and tweak the BFR91 preamp for best VSWR and then revisit this with a bit more time. I'll also use averaging and I'll accurately measure the small signal gain with a 2 port VNA (calibrated with an Ecal module).
?
Although this result looks good, I don't think it's worth trying to use it below 2MHz with the 346A noise source as the ENR of this 346A really drops down quite quickly below 2MHz.
?
My homebrew noise source using a Noisecom noise diode is probably more suitable for use below 2MHz as the diode is supposed to work down to 200kHz and HPAK suggest that the analyser can be used down to 200kHz in noise figure mode. I'm not convinced of this though. It will also take ages to do the measurement as it dynamically reduces the detection bandwidth for lower frequencies and this really slows it down.
?
?
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Hi, Indeed, it seems that you have problems with hybrid amplifiers. I found the table showing the different values ??associated with the pins surrounding this hybrid. It is certain that a bad polarization will affect the hybrid, just like for the uPA204. ? If you have a chance to do it, I would like to know the different voltages and waveforms associated with the u203 upa204. Because for the moment, nothing suggests that u203 is OK, unless you have made new measurements and the signals are normal. ? 
? Yves ? Thanks for the info and simulation data. I will have a look at pin 2 and check. I actually switched focus to the 2nd unit which has the same E304 error and low output on channel 1. I checked the output of the transducer board and it measured the same as channel 2 (which does work). I then measured the output of the hybrid amplifier and it was much lower when compared to channel 2.? So it looks like that has a hybrid amplifier problem. Which is odd because E304 relates to the output of the transducer board. Output of the hybrid amplifier should trigger a different fault code ? Anyway, I tried swapping the hybrid over from the first unit... and I got no output at all then, same fault as the first unit. Swapped the hybrids back over again and got the low output fault back.? So I can only conclude at this point that both hybrid amplifiers are faulty. One with no output, and one with very low output.? I wondered if the one with no output is somehow shutting down the output of the transducer board. Some sort of protection kicking in because the symptoms transfer across when I swap the hybrids over. There is a UPA102G on the hybrid. It MIGHT be worth swapping this with another one.??
|
Chuck said:
"Come on guys, it really isn't that bad. ?The stuff he?
is talking about is a petroleum jelly based zinc chloride
compound. ?Zinc Chloride is a killed acid. ?That means that
they dissolve enough zinc into HCL that it can take no more,
and is neutral pH.
It is non-corrosive, and says so in bold red letters right?
on the can."
Not according to who say "It is corrosive to metals"
The key is in the "chloride". I don't know how you determined the OP had a jelly based flux as he didn't say.
Not all flux is corrosive. Rosin flux is not. It does not have to be it works by excluding air (oxygen) from the hot joint.
A solution fod zinc hloride is acidic with a PH of about 4. It is not suitable for electrical applications.
?
Robert.
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Locked
Re: Fees due soon for the group - please sponsor it.
Is this someone gathering material for a sociology paper?? :-/
Barry - N4BUQ
Hi Dave,
I tried to get to the sponsor page and it just took me to the
front page. Tried adding the /sponsor to the URL in my browser and
that just took me back to the front page. Seems there is an issue.
73s
Brian Flynn GM8BJF
On 17/10/2024 13:31, Dr. David Kirkby,
Kirkby Microwave Ltd wrote:
The fee ($110) for the group are due at the end of the month,
so I'd like to request that you consider sponsoring the group.
Last time I asked this, the amount of money collected in a short
time far exceeded what was needed. I'm reluctant to let a lot of
money build up, since it's non refundable, so I disabled the
ability to sponsor the group.?Quite a few people were
disappointment that they could not contribute.
?
Could I suggest that
?
1) You only donate $5.
2) You don't donate if you have already done so before.
?
That will need just 22 people to donate. If after a couple of
days there's not enough money, I'll ask people to add a bit
more, but based on previous experience, the amount needed will
soon be reached.
?
Also, please do not send money to my email address by
PayPal - this is a business email address, and it would cause
me problems.
?
So if you have not donated before, click this link to donate
$5.
?
?
Dave
--
Dr Brian W Flynn
15 Riselaw Crescent
Edinburgh
EH10 6HN
Home 0131 447 4043
Mob 07969668147
|
Thanks for the info and simulation data. I will have a look at pin 2 and check.
?
I actually switched focus to the 2nd unit which has the same E304 error and low output on channel 1. I checked the output of the transducer board and it measured the same as channel 2 (which does work). I then measured the output of the hybrid amplifier and it was much lower when compared to channel 2.?
?
So it looks like that has a hybrid amplifier problem. Which is odd because E304 relates to the output of the transducer board. Output of the hybrid amplifier should trigger a different fault code ?
?
Anyway, I tried swapping the hybrid over from the first unit... and I got no output at all then, same fault as the first unit. Swapped the hybrids back over again and got the low output fault back.?
?
So I can only conclude at this point that both hybrid amplifiers are faulty. One with no output, and one with very low output.?
?
I wondered if the one with no output is somehow shutting down the output of the transducer board. Some sort of protection kicking in because the symptoms transfer across when I swap the hybrids over.
?
There is a UPA102G on the hybrid. It MIGHT be worth swapping this with another one.??
|
Locked
Re: Fees due soon for the group - please sponsor it.
Hi Dave,
I tried to get to the sponsor page and it just took me to the
front page. Tried adding the /sponsor to the URL in my browser and
that just took me back to the front page. Seems there is an issue.
73s
Brian Flynn GM8BJF
On 17/10/2024 13:31, Dr. David Kirkby,
Kirkby Microwave Ltd wrote:
The fee ($110) for the group are due at the end of the month,
so I'd like to request that you consider sponsoring the group.
Last time I asked this, the amount of money collected in a short
time far exceeded what was needed. I'm reluctant to let a lot of
money build up, since it's non refundable, so I disabled the
ability to sponsor the group.?Quite a few people were
disappointment that they could not contribute.
?
Could I suggest that
?
1) You only donate $5.
2) You don't donate if you have already done so before.
?
That will need just 22 people to donate. If after a couple of
days there's not enough money, I'll ask people to add a bit
more, but based on previous experience, the amount needed will
soon be reached.
?
Also, please do not send money to my email address by
PayPal - this is a business email address, and it would cause
me problems.
?
So if you have not donated before, click this link to donate
$5.
?
?
Dave
--
Dr Brian W Flynn
15 Riselaw Crescent
Edinburgh
EH10 6HN
Home 0131 447 4043
Mob 07969668147
|
Locked
Re: Fees due soon for the group - please sponsor it.
It would have been very much better to replace the sponsor/donate page content, with a "thank you" message, rather than just take it down in the event sufficient funds were quickly donated.
I'll say no more..
73.
Dave 'kbv.
|
My mistake.? ?Thanks for the correction, jmr.? Hmmm...? digital AWGN generation, eh?? Sounds like a fun project to be filed away in the Someday File.? Jim
On Thu, Oct 17, 2024 at 9:44 AM, jmr via groups.io <jmrhzu@...> wrote: I think Marko is referring to a 'digital' noise source. I've got various digital noise sources here and some are built into vector signal generators.?
?
For example, an additive white gaussian noise generator (AWGN) can generate noise quite accurately. These can be homebrew or you can buy them. The AWGN feature in my sig gens can be set to have a random seed and then it produces a long random sequence of noise. It does repeat itself after a while but the repeat rate can be controlled in the menu. It's possible to define the bandwidth and the power level of the noise. A decent attenuator would be needed in order to get the level down to a very low level. A typical RF sig gen can do this with it's internal step attenuator.
?
I think the main niggle with using the 346A below 10MHz is the low ENR it offers and this gets lower at frequencies below about 2 or 3 MHz. The noise floor of a typical RF/Microwave spectrum analyser will gradually rise below 10MHz and this increases the overall measurement uncertainty when trying to measure noise figure with a low ENR noise source. The noise figure analysers are only spec'd down to 10MHz and I'm only aware of one HPAK RF/microwave spectrum analyser that can work with the 346A below 10MHz with reasonably low uncertainty. Even then, it isn't an ideal combination.
?
?
|
Thanks for all the replys on this topic, I will refrain from using this Flux in future ( except maybe if I have to solder a thick ground wire to a plated chassis maybe! ) ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?Regards Brad?
On Thu, Oct 17, 2024, 20:05 Michael A. Terrell via <terrell.michael.a= [email protected]> wrote: That is highly corrosive flux intended for plumbing, not electronics. Don't use it on anything electronic, .
On Thu, Oct 17, 2024 at 4:57?AM Brad Latta via <bradley.latta= [email protected]> wrote: I have some old solder Flux here that I use for cleaning up oxidized & dirty connections when I replaced components in vintage HP equipment, this Flux has 27% Zinc Chloride, which really helps to wet the connection for soldering. I am wondering how bad is the Zinc Chloride, and what precautions should I take when using it?, maybe someone here has used a similar Flux before,? ? ? ? ? ? ? ? ? ?Brad
|
Locked
Re: Fees due soon for the group - please sponsor it.
I am pretty sure, as John G has pointed out, donations are currently closed. I suggest?we close this topic for the time being, that is until?we need to pass the hat again to keep the forum?active. Radu.?
On 2024-10-17 06:31, Dr. David Kirkby, Kirkby Microwave Ltd wrote:
> The fee ($110) for the group are due at the end of the month, so I'd
> like to request that you consider sponsoring the group. Last time I
> asked this, the amount of money collected in a short time far exceeded
> what was needed. I'm reluctant to let a lot of money build up, since
> it's non refundable, so I disabled the ability to sponsor the group.
> Quite a few people were disappointment that they could not contribute.
>
>
> Could I suggest that
>
> 1) You only donate $5.
> 2) You don't donate if you have already done so before.
>
> That will need just 22 people to donate. If after a couple of days
> there's not enough money, I'll ask people to add a bit more, but based
> on previous experience, the amount needed will soon be reached.
>
> Also, please do not send money to my email address by PayPal - this is
> a business email address, and it would cause me problems.
>
> So if you have not donated before, click this link to donate $5.
>
> /g/HP-Agilent-Keysight-equipment/sponsor
>
> Dave
>
>
> Links:
> ------
> [1] /g/HP-Agilent-Keysight-equipment/message/147962
> [2] /mt/109062502/803518
> [3] /g/HP-Agilent-Keysight-equipment/post
> [4] /g/HP-Agilent-Keysight-equipment/editsub/803518
> [5]
> /g/HP-Agilent-Keysight-equipment/leave/12430099/803518/829267165/xyzzy
Happy to donate - WHERE on the page is the link to do so ???
Cheers!
Bruce
|
Locked
Re: Fees due soon for the group - please sponsor it.
On 2024-10-17 06:31, Dr. David Kirkby, Kirkby Microwave Ltd wrote: The fee ($110) for the group are due at the end of the month, so I'd
like to request that you consider sponsoring the group. Last time I
asked this, the amount of money collected in a short time far exceeded
what was needed. I'm reluctant to let a lot of money build up, since
it's non refundable, so I disabled the ability to sponsor the group.
Quite a few people were disappointment that they could not contribute.
Could I suggest that
1) You only donate $5.
2) You don't donate if you have already done so before.
That will need just 22 people to donate. If after a couple of days
there's not enough money, I'll ask people to add a bit more, but based
on previous experience, the amount needed will soon be reached.
Also, please do not send money to my email address by PayPal - this is
a business email address, and it would cause me problems.
So if you have not donated before, click this link to donate $5.
/g/HP-Agilent-Keysight-equipment/sponsor
Dave
Links:
------
[1] /g/HP-Agilent-Keysight-equipment/message/147962
[2] /mt/109062502/803518
[3] /g/HP-Agilent-Keysight-equipment/post
[4] /g/HP-Agilent-Keysight-equipment/editsub/803518
[5] /g/HP-Agilent-Keysight-equipment/leave/12430099/803518/829267165/xyzzy Happy to donate - WHERE on the page is the link to do so ??? Cheers! Bruce
|
I think Marko is referring to a 'digital' noise source. I've got various digital noise sources here and some are built into vector signal generators.?
?
For example, an additive white gaussian noise generator (AWGN) can generate noise quite accurately. These can be homebrew or you can buy them. The AWGN feature in my sig gens can be set to have a random seed and then it produces a long random sequence of noise. It does repeat itself after a while but the repeat rate can be controlled in the menu. It's possible to define the bandwidth and the power level of the noise. A decent attenuator would be needed in order to get the level down to a very low level. A typical RF sig gen can do this with it's internal step attenuator.
?
I think the main niggle with using the 346A below 10MHz is the low ENR it offers and this gets lower at frequencies below about 2 or 3 MHz. The noise floor of a typical RF/Microwave spectrum analyser will gradually rise below 10MHz and this increases the overall measurement uncertainty when trying to measure noise figure with a low ENR noise source. The noise figure analysers are only spec'd down to 10MHz and I'm only aware of one HPAK RF/microwave spectrum analyser that can work with the 346A below 10MHz with reasonably low uncertainty. Even then, it isn't an ideal combination.
?
?
|
Locked
Re: Fees due soon for the group - please sponsor it.
On 10/17/24 08:51, Dave_G0WBX via groups.io wrote: Give us a clue Dave, as to what to look for on the group landing page re donation. The sponsor page does not lead to anything now. Probably since Dave said he had closed donations.
|
In 1968, the high school I attended was brand new.? The
intercom/building PA was DuKane, a marginal company at best. The
school also had an extremely elaborate language lab system made by
Chester Electronics. That system also allowed the on demand
playing of selected audio tapes in the classrooms through the PA
speakers in the rooms. The interfacing between the systems was a
failure and caused horrific problems. It never worked. With regard
to Zinc chloride fluxes, I have used them to tin old and
improperly stored connectors before installing them.? After
tinning them, I cleaned them off thoroughly with hydrocarbon
solvent to get the wax and petroleum jelly off, followed by a good
scrubbing with hot water and dishwasher detergent and the hottest
rinse possible. I megged them with a 600 volt megger, and had zero
leakage or problems.? I think you could use these fluxes on a
badly corroded epoxy fiberglass circuit board, but not a fibre
one.? The serious cleaning is still needed.? There are paste
fluxes designed for SMD work that are said to be non conductive
and non corrosive, I have used them with great results on boards
and wiring that needs them. I do wash them off? with spray solvent
contact cleaner without lube.
?????? Bruce Gentry, KA2IVY
On 10/17/24 11:07, Michael A. Terrell
wrote:
toggle quoted message
Show quoted text
I serviced school intercoms for years. The Dukane
authorized company was supposedly run by Electrical Engineers.
Their designs and installations were pure garbage.
|
Thanks Joel!
?
I’ll report back here with my findings.?
|
Locked
Re: Fees due soon for the group - please sponsor it.
I too tried to donate.? The link takes me to the front page of the group.? Any suggestions???
Kim Herron? W8ZV
w8zv@...
www.goldenradioservice.com
616-677-3706
??
-- Kim Herron W8ZV w8zv at goldenradioservice dot com www.goldenradioservice.com
|
On Thursday 17 October 2024 10:34:34 am Nick Andrews wrote: You should see some of the mess we are cleaning up in VA hospitals,
replacing their entire IT infrastructure, data centers, etc at multiple
locations. Their existing IT closets are literally in most cases closets,
barely big enough for a two-post rack. Many have zero cooling whatsoever!
Many have cat 5 and older patch cables piled up (while still in use)
against the door two feet deep, the door holding them in when closed! New
standards require Cat 6a cabling and telecom rooms a minimum of 80SF in
non-clinical areas. That's for a single cabinet (replacing all old open
racks with enclosed cabinets). More cabinets, more space. Old nurse call,
analog phone stuff, etc all over the place and out of our scope but still
in the way. The program office in DC wants to eliminate raised floor
systems, claiming they cannot cool the equipment and want to see new
hot/cold aisle containment with cold air pumped into the aisle between
front of rows to flow through. Even seeing the CFD analysis I am not
convinced this is the way to go... One service call I remember that really sticks in my memory was at a hotel. All sorts of equipment, including phones, computer networking, wifi, and a bunch of other stuff all terminated in one area. Which also happened to be the terminus for their laundry chute! The dust from all those sheets and such got into *everything*, and I'm sure that there was some biohazard there as well. You can probably imagine the overheating problems caused by all of that dust. I had some trouble putting together a recommendation for them to correct this situation, and they sure didn't seem to be inclined to do anything about it, even though I told 'em that there was going to be further trouble with all of this stuff in the not-too-distant future... On Thu, Oct 17, 2024 at 9:21?AM Matt Harris via groups.io <kd4pbs=
[email protected]> wrote:
I'll never forget the tech hell I was exposed to in my early 20s when I
worked for a local repair facility specializing in, among other things,
intercom systems in schools and prisons. The company had one other
competitor in the area, and we were constantly having to clean up messes
they made on many different PA, intercom, and fire alarm, and nurse call
systems all across the state. It seems that they had a "tech" that worked
on their install team who enjoyed using flux designed for plumbing, not
electronics, on most of his work. An inordinate amount of my time was
spent sweeping up after that particular elephant. My "favorite" anecdote
was the week I had spent putting in 66 blocks to replace 15-some "Christmas
tree" blocks which had terminals literally rusted and rotting away due to
Cletus' (the fictitious name we bestowed upon whoever it was at that
company that did this) use of that flux a few decades before. The whole
terminal lug would end up rusting through and literally detaching itself
from the block. All that one would see is the end of a wire with a little
nub of rust left, dangling in the breeze, without a clue as to where it and
it's other identical twins used to be connected. Thankfully there was
usually plenty of slack in the lines fanning out to the facilities, or that
could have gone even more sideways quickly.
I couldn't change my career path fast enough after dealing with stuff like
this. -- Member of the toughest, meanest, deadliest, most unrelenting -- and ablest -- form of life in this section of space, ?a critter that can be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters" - Information is more dangerous than cannon to a society ruled by lies. --James M Dakin
|
I serviced school intercoms for years. The Dukane authorized company was supposedly run by Electrical Engineers. Their designs and installations were pure garbage. One school board's electricians did dangerous repairs, as well. One intercom console used relays instead of the built in switch for all call. The monos used an exposed 120VAC relay, with the terminals exposed. One of the electricians had 'repaired' the control panel by soldering 12 inch writes to a bad electrolytic capacitor and letting an axial capacitor hung into the turntable drawer. It was over 400VDC. The most fun I had was telling a Principal that I had to completely overhaul the system. He was used to the bad work of the deler and electricians so he refused. I told him I had it working temporarily, but I would be back at the end of school on Friday to remove it, and return it on Monday. I cleaned up all the bad repairs, then added a 50 pinn blue ribbon cable? to connect to the classrooms. I had 66 bloks with the connector, so any future repairs would be easy. I had it working 15 minutes after normal morning announcements, because the janitor was 30 minutes late unlocking the building. The principal had apparently told him that I wouldn't show up because he wasn't expecting me.
The dealer expanded the system at my high school. It was RCA. They added two 100W Dukane amps, but couldn't figure out why the audio was severely distorted, so they disconnected them. Those 'engineers' couldn't figure out that the two different amplifiers were 180 degrees out of phasee.
I'll never forget the tech hell I was exposed to in my early 20s when I worked for a local repair facility specializing in, among other things, intercom systems in schools and prisons.? The company had one other competitor in the area, and we were constantly having to clean up messes they made on many different PA, intercom, and fire alarm, and nurse call systems all across the state.? It seems that they had a "tech" that worked on their install team who enjoyed using flux designed for plumbing, not electronics, on most of his work.? An inordinate amount of my time was spent sweeping up after that particular elephant.? My "favorite" anecdote was the week I had spent putting in 66 blocks to replace 15-some "Christmas tree" blocks which had terminals literally rusted and rotting away due to Cletus' (the fictitious name we bestowed upon whoever it was at that company that did this) use of that flux a few decades before.? The whole terminal lug would end up rusting through and literally detaching itself from the block.? All that one would see is the end of a wire with a little nub of rust left, dangling in the breeze, without a clue as to where it and it's other identical twins used to be connected.? Thankfully there was usually plenty of slack in the lines fanning out to the facilities, or that could have gone even more sideways quickly.
I couldn't change my career path fast enough after dealing with stuff like this.
|
Brad Jackson
Michael A. Terrell