Re: An update on sponsoring the group.
Sorry to hear you got some grief out of this.? I thought your email was pretty clear.? And you immediately informed everyone once the quota was met.? Would love to donate as well, so hopefully I'll be fast enough next year.??
?
As Jim said, thank you for allowing this group to exist!
?
-Frank
?
|
Re: An update on sponsoring the group.
I'm sorry to hear that you received some flak. I am glad for what you are doing for all of us with this group.
?
Best regards,
?
Jim
|
An update on sponsoring the group.
I posted a link earlier today requesting that people that had not sponsored the group before could consider doing so by denoting $5. My post seems to have raised a lot of concerns and emails, so I want to explain what happened.?
?
I know many people wanted to donate, but I don¡¯t want to build up a big piggy bank of money to which we have no access. If group.io folded we would have no access to the money. It¡¯s non-refundable. So I'd rather have enough money to cover fees, but not an excessive amount. Hence I requested donations were only $5, and only if you had not already donated.
?
IMHO groups.io have been very fair, and our fees for the group have been fixed at $110/year, despite new groups getting less facilities paying $220/year. Groups dot io seem to be keeping the fees constant - they are not rising inline with inflation. We are considered a legacy group.
We had got enough money to cover the fees within 20 minutes, of my post, so I disabled the sponsor function. I have received a lot of private emails, mentions on here, and even a complaint about the way it was handled, so I thought I'd try to clarify why I did it the way I did, and how? you can usefully donate to a charity if you want to.
Firstly, the link that ended in /sponsor is created and destroyed by groups.io automatically, depending upon whether I enable the sponsorship feature. So I could not, ?as someone suggested, put a custom message. Those of you who tried donating later got a 404 error. Next time I will look into creating a custom message, which itself has a link to the sponsor, but warns that unless you are quick, you will likely not be able to donate.
If anyone wanted to donate, but was unable to, then please consider donating to one of the following charities. All want payment in UK pounds (GBP), but PayPal, a credit or debit card will just convert whatever you donate to your own currency.
?
If you don't want to deal in GBP, then you can send whatever currency you want to my personal PayPal address (drkirkby@...), and I will ensure it gets to the charity of your choosing. Please do not send to my business email address drkirkby@....
I put below in alphabetical order, a suggested list of UK charities. I know some people like donating to small charities. The third in the list is 100% voluntary, with zero employees. The fourth in the list is very small.? The other charities are better known, and bigger.
?
1) Cat¡¯s Protection League
?
2) Dog's Trust
?
3) German Shepherd Dog Rescue (100% voluntary, zero employees).
https://www.germanshepherdrescue.co.uk/donate-german-shepherd-rescue-i-84.html
(Declared conflict of interest, I own a German Shepherd)
?
4) Girlguiding (A small charity, but it does have paid employees)
This helps? young girls develop new skills and build self-confidence.
?
5) Open University
https://giving.open.ac.uk/make-a-gift
This provides education, including degrees. The courses are very high quality, but funding is tight.
?
A lot of material is made freely available too.
(Declared conflict of interest, I'm currently doing a BSc (honors) degree in mathematics at the Open University)
?
6) Royal Society for the Prevention of Cruelty to Animals (RSPCA)
?
?
?
|
Locked
Re: Fees due soon for the group - please sponsor it.
As I was too slow this year. If people heed Dave¡¯s admonition not to donate if they have donated in the past, we¡¯ll eventually get our opportunity to chip in $5 to keep this useful service going.
I appreciate that there are so many on the list who stepped up before I was awake to keep the next year¡¯s fees paid.
toggle quoted message
Show quoted text
On Oct 17, 2024, at 17:43, romeo987 <Snicko68@...> wrote:
?
I was too slow last year¡
The link just takes me to the group home page and I can¡¯;t find a ¡°sponsor¡± tab
Roman
|
RMA flux is mildly activated rosin. If you need something stronger, the components are damaged. I have only used acid flux to solder brass or steel pieces together to make a chassis or shielding, then wire brushed it and reflowed it with rosin flux. I use a solder pot to pretin most connectors. I moved and rebuilt a 1952 RCA TV transmitter, a couple decades ago. I used silver solder for the cooling system. I tinned the pipe and fittings, wiping away the excess solder. Then I suded rosin cored solder , because the cooling system had 7KV across it. It? required 100 Megohm per cubic centimeter purity in the coolant. The slightest bit of acid flux would contaminate hundreds of gallons of distilled water & antifreeze. Pre tinned pipe and fittings were a breeze to solder, with a torch. it wicked all the way inside, then formed a smooth bead all around the exterior. without trying since the flux didn't have to carry off any oxides, It also meant that there were no leaks. Some previous 'plumber/engineer had brazed over the leaks form their bad solder job. The fittings were custom made and NLA, so I had to saw off the old copper pipe , then heat it as I pried the old pipe loose , then work it back & forth until the brazing broke. That was followed by carefully filing away just the burs, before reassembly. It was a lot of extra work, caused by someone who couldn't do decent soldering. BTW, it only had two semiconductors. Tey were in customized Bird 43 wattmeter to read the drive level to the final tubes.
On Thu, Oct 17, 2024 at 4:40?PM Robert G8RPI via <robert8rpi= [email protected]> wrote: 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.
|
Locked
Re: Fees due soon for the group - please sponsor it.
I was too slow last year¡ The link just takes me to the group home page and I can¡¯;t find a ¡°sponsor¡± tab Roman
toggle quoted message
Show quoted text
On 17 Oct 2024, at 11:01?PM, Dr. David Kirkby, Kirkby Microwave Ltd via groups.io <drkirkby@...> 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
|
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.
?
?
|
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.
|
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.
?
?
|
Frank Mashockie
Dr. David Kirkby, Kirkby Microwave Ltd
Michael A. Terrell