Amplifer Design

[Winfield Hill]

Cursitor Doom wrote...

Winfield Hill wrote:
Cursitor Doom wrote...

... drop a couple of closely-matched jellybeans in there in
place of Q8 and Q13 and in this x-amp at any rate, given its
modest task, will quickly be back in business again.

The two BJTs are npn and pnp types and cannot easily be closely
matched, nor do they need to be.** Plop some parts in there
and let us know what happens.

** Recenter the screen with the HORIZ POSN control.

Indeed so. I'm guessing the hardest part is going to
be finding PNPs in my junk box that are fast enough.

Any old PNP will be fine, tit doesn't have to be fast,
the collector is going into a summing junction. Even
a 2N3904 / 2N3906 will work fine.


--
Thanks,
- Win

 

[Winfield Hill]

Jan Panteltje wrote...

I bought a 2400 W water boiler, for coffee that is.
Plugging it in did indeed boil 1.5 liter water in
about 3 minutes, but it also caused a dip ...

2400 watts, that's ridiculous. The most they sell
here is 1500 watts, that's more than fast enough.
Trade it in for a smaller one.


--
Thanks,
- Win

 

On Wednesday, 16 October 2019 16:24:34 UTC+1, Winfield Hill wrote:

Jan Panteltje wrote...

I bought a 2400 W water boiler, for coffee that is.
Plugging it in did indeed boil 1.5 liter water in
about 3 minutes, but it also caused a dip ...

2400 watts, that's ridiculous. The most they sell
here is 1500 watts, that's more than fast enough.
Trade it in for a smaller one.

Not at all. I just checked the rating label on my "electric kettle".
(Almost every household in the UK has one of these.)
Mine is rated at 220 - 240V, 2500 - 3000W.

Most UK household mains supplies are about 240V single phase and
have a main fuse rated at 80 or 100A. Larger houses often have
3-phase 240V (phase to neutral) at 100A per phase.

(The "official" voltage is 230V but this is just for harmonisation
purposes with the rest of the EU. The specified tolerances allow
the real voltage to be around 240V for most areas.)

John

 

[Jan Panteltje]

On a sunny day (16 Oct 2019 08:24:14 -0700) it happened Winfield Hill
<winfieldhill@yahoo.com> wrote in <qo7cmu0q6g@drn.newsguy.com>:

Jan Panteltje wrote...

I bought a 2400 W water boiler, for coffee that is.
Plugging it in did indeed boil 1.5 liter water in
about 3 minutes, but it also caused a dip ...

2400 watts, that's ridiculous. The most they sell
here is 1500 watts, that's more than fast enough.
Trade it in for a smaller one.

No, I already like it very much:
https://www.artencraft.nl/nl/siemens-tw86103p-waterkoker-15l-zwart-268677.html?gclid=EAIaIQobChMIzKqirJmh5QIVRuJ3Ch1hnwA2EAQYASABEgLmFfD_BwE

Electronic control

It is more efficient than boiling water in the microwave (what I did till now)
That way it will pay itself back in a few years.
And it is made in the EU by an EU based (German) company.
As the US pRecedent likes damaging world trade I answer by not buying US stuff.

1500 W PUSSIES!!!
;-)

Found some good Linux laptops locally for sale..

 

[Martin Brown]

On 16/10/2019 16:24, Winfield Hill wrote:

Jan Panteltje wrote...

I bought a 2400 W water boiler, for coffee that is.
Plugging it in did indeed boil 1.5 liter water in
about 3 minutes, but it also caused a dip ...

2400 watts, that's ridiculous. The most they sell
here is 1500 watts, that's more than fast enough.
Trade it in for a smaller one.

Most UK kettles are 3kW although there is a trend towards 2.4kW for new
portable appliances as the full 13A load stresses the fused plugs
somewhat. Much more of a problem with electric fan heaters than kettles
which typically only present a load for a couple of minutes at most.

--
Regards,
Martin Brown

 

On Wed, 16 Oct 2019 07:31:21 GMT, Jan Panteltje
<pNaOnStPeAlMtje@yahoo.com> wrote:

LOL
not everybody is the same, I am fighting with software.
Real fun, my systems got attacked by one of the most evil ones, the well known Jan Panteltje.
I bought a 2400 W water boiler, for coffee that is.
Plugging it in did indeed boil 1.5 liter water in about 3 minutes, but it also caused a dip in the mains
that in turn caused my main PC reiserfs to see bad sectors,
Rescue failed.

2400 W is only 10 A steady state i.e. 24 ohm resistance.

Unfortunately the cold resistance is quite low, until the resistor
reaches nominal operating temperature, so the cold start current can
be much larger than 10 A.

 

[Cursitor Doom]

On Wed, 16 Oct 2019 08:20:00 -0700, Winfield Hill wrote:

Any old PNP will be fine, tit doesn't have to be fast,
the collector is going into a summing junction. Even a 2N3904 / 2N3906
will work fine.

Well I'm mightily relieved you said that, Win, because I do happen to
have a very large amount of both polarities in stock. THANKS!!!



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[Cursitor Doom]

On Wed, 16 Oct 2019 16:35:58 +0000, Jan Panteltje wrote:

1500 W PUSSIES!!!
;-)

Found some good Linux laptops locally for sale..

Are you going to Rosmalin for the big electronics swap meet next March,
Jan?



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[Clifford Heath]

On 15/10/19 7:20 pm, Jan Panteltje wrote:

I was referring to mixing down 2.4 GHz to 1.5 GHz or so for use with an RTL_SDR USB stick as spectrum analyzer,
that I did.
....
So, as to GHz:
https://www.ebay.com/itm/272411458376
much more fun to play with than old boat_anchors.
that is what my xpsa spectrum analyzer software runs on.

The RTL-SDR (listening) community seems to think that this genuine
"RTL-SDR v3 Blog" version is very much better than the cheap generic TV
dongles that have the same chipset. Ok, I grant that it has a TCXO and
the "Q-branch" mod for HF listening, but...

What else is it about this specific dongle that makes it better? If you
know and have time to answer, of course...

Clifford Heath

 

[Cursitor Doom]

On Thu, 17 Oct 2019 09:38:31 +1100, Clifford Heath wrote:

The RTL-SDR (listening) community seems to think that this genuine
"RTL-SDR v3 Blog" version is very much better than the cheap generic TV
dongles that have the same chipset. Ok, I grant that it has a TCXO and
the "Q-branch" mod for HF listening, but...

What else is it about this specific dongle that makes it better? If you
know and have time to answer, of course...

SDR is pretty amazing for its size and cost, but in terms of sensitivity
and selectivity you really cannot beat good old fashioned physical
components built specifically for the purpose: rock solid silver mica
capacitors and carefully cut and trimmed, temp-stabilised quartz crystals
for frequency control; large, open wound, well-spaced gold plated
inductors for high Q tuned circuits. You'll never successfully emulate
qualities like those in software. NEVER!!


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[Cursitor Doom]

On Wed, 16 Oct 2019 19:43:09 +0000, Cursitor Doom wrote:

Well I'm mightily relieved you said that, Win, because I do happen to
have a very large amount of both polarities in stock. THANKS!!!

Just wondering if I should try to match pairs by Beta as closely as
possible. I have a nagging suspicion I really should make that extra
little bit of effort.



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[Winfield Hill]

Cursitor Doom wrote...

On 16 Oct 2019, Cursitor Doom wrote:

Well I'm mightily relieved you said that, Win, because I do happen to
have a very large amount of both polarities in stock. THANKS!!!

Just wondering if I should try to match pairs by Beta as closely as
possible. I have a nagging suspicion I really should make that extra
little bit of effort.

Although this is an old design, it adheres well to the BJT design
philopsohy I learned in the late 60s. Which is to rely on accurate
Ebers-Moll transconductance characteristics, and stay away from the
uncertain beta, and similar aspects of a transistor, in the circuit
design. So you don't need to match beta, Vbe, or other perameters.


--
Thanks,
- Win

 

[Clifford Heath]

On 17/10/19 10:39 am, Cursitor Doom wrote:

On Thu, 17 Oct 2019 09:38:31 +1100, Clifford Heath wrote:

The RTL-SDR (listening) community seems to think that this genuine
"RTL-SDR v3 Blog" version is very much better than the cheap generic TV
dongles that have the same chipset. Ok, I grant that it has a TCXO and
the "Q-branch" mod for HF listening, but...

What else is it about this specific dongle that makes it better? If you
know and have time to answer, of course...

SDR is pretty amazing for its size and cost, but in terms of sensitivity
and selectivity you really cannot beat good old fashioned physical
components built specifically for the purpose: rock solid silver mica
capacitors and carefully cut and trimmed, temp-stabilised quartz crystals
for frequency control; large, open wound, well-spaced gold plated
inductors for high Q tuned circuits. You'll never successfully emulate
qualities like those in software. NEVER!!

Yes, I know and agree about SDR (though it can do other things that are
very complex in discrete, like order-100 filters, etc). I asked about
this specific RTL2832U dongle being supposedly better than other ones.
I'm amazed at the fan-dom it has garnered, being a crappy little 8-bit
thing on USB.

 

[Jasen Betts]

On 2019-10-16, upsidedown@downunder.com <upsidedown@downunder.com> wrote:

On Wed, 16 Oct 2019 07:31:21 GMT, Jan Panteltje
pNaOnStPeAlMtje@yahoo.com> wrote:

LOL
not everybody is the same, I am fighting with software.
Real fun, my systems got attacked by one of the most evil ones, the well known Jan Panteltje.
I bought a 2400 W water boiler, for coffee that is.
Plugging it in did indeed boil 1.5 liter water in about 3 minutes, but it also caused a dip in the mains
that in turn caused my main PC reiserfs to see bad sectors,
Rescue failed.

2400 W is only 10 A steady state i.e. 24 ohm resistance.

Unfortunately the cold resistance is quite low, until the resistor
reaches nominal operating temperature, so the cold start current can
be much larger than 10 A.

It could be as low as 22 ohms when cold. but I can't see an xtra half-amp
making a big difference.




--
When I tried casting out nines I made a hash of it.

 

[Jan Panteltje]

On a sunny day (Wed, 16 Oct 2019 23:39:41 -0000 (UTC)) it happened Cursitor
Doom <curd@notformail.com> wrote in <qo89nt$4lg$6@dont-email.me>:

On Thu, 17 Oct 2019 09:38:31 +1100, Clifford Heath wrote:

The RTL-SDR (listening) community seems to think that this genuine
"RTL-SDR v3 Blog" version is very much better than the cheap generic TV
dongles that have the same chipset. Ok, I grant that it has a TCXO and
the "Q-branch" mod for HF listening, but...

What else is it about this specific dongle that makes it better? If you
know and have time to answer, of course...

SDR is pretty amazing for its size and cost, but in terms of sensitivity
and selectivity you really cannot beat good old fashioned physical
components built specifically for the purpose: rock solid silver mica
capacitors and carefully cut and trimmed, temp-stabilised quartz crystals
for frequency control; large, open wound, well-spaced gold plated
inductors for high Q tuned circuits. You'll never successfully emulate
qualities like those in software. NEVER!!

No T-Ford either!

Again, do you have a cellphone?

 

[Jan Panteltje]

On a sunny day (Thu, 17 Oct 2019 09:38:31 +1100) it happened Clifford Heath
<no.spam@please.net> wrote in <HZMpF.21095$5X.7513@fx15.iad>:

On 15/10/19 7:20 pm, Jan Panteltje wrote:
I was referring to mixing down 2.4 GHz to 1.5 GHz or so for use with an RTL_SDR USB stick as spectrum analyzer,
that I did.
...
So, as to GHz:
https://www.ebay.com/itm/272411458376
much more fun to play with than old boat_anchors.
that is what my xpsa spectrum analyzer software runs on.

The RTL-SDR (listening) community seems to think that this genuine
"RTL-SDR v3 Blog" version is very much better than the cheap generic TV
dongles that have the same chipset. Ok, I grant that it has a TCXO and
the "Q-branch" mod for HF listening, but...

What else is it about this specific dongle that makes it better? If you
know and have time to answer, of course...

Clifford Heath

Well I have the time,
nyways what is time .. relativity.. OK
As with everything (like cars) people have preferences.
Indeed the TCXO is great,
But .. you can specify angt frequency error in rtl_sdr with the -p flag to compensate.
When you have the thing warm up for some time even without TCXO the drift is maybe 2 ppm
(for my old ones that is).
For most purposes that is fine.
I have a rubidium reference (ebay) and cheched the ebay TXCO sticks against it,
and for one I added a 1 ppm correction (assuming the rubidium is exact).
Good enough for me.
As to sensitivity I am not sure, seems much the same to me.
I did GPS with the E4000.


I have 2 of the ebay TCXO ones, rtl_test shows this on the laptop:
~# rtl_test
Found 1 device(s):
0: ezcap USB 2.0 DVB-T/DAB/FM dongle
Using device 0: ezcap USB 2.0 DVB-T/DAB/FM dongle
Found Rafael Micro R820T tuner
Supported gain values (29): 0.0 0.9 1.4 2.7 3.7 7.7 8.7 12.5 14.4 15.7 16.6 19.7 20.7 22.9 25.4 28.0 29.7 32.8 33.8 36.4 37.2 38.6 40.2 42.1 43.4 43.9 44.5 48.0 49.6


Then I have a very old no TCXO one that one runs on a Raspberry Pi receiving AIS (ship data):
root@raspberrypi:~# rtl_test
Found 1 device(s):
0: ezcap USB 2.0 DVB-T/DAB/FM dongle
Using device 0: ezcap USB 2.0 DVB-T/DAB/FM dongle
Found Rafael Micro R820T tuner
Supported gain values (29): 0.0 0.9 1.4 2.7 3.7 7.7 8.7 12.5 14.4 15.7 16.6 19.7 20.7 22.9 25.4 28.0 29.7 32.8 33.8 36.4 37.2 38.6 40.2 42.1 43.4 43.9 44.5 48.0 49.6

So that one looks a lot like the same chip, but no TCXO, corection needed +46 ppm

Rx AIS with the one:
rtl_fm -f 161975000 -p 46 -s 48k -r 48k | aisdecoder -d -h 127.0.0.1 -p 10123 -a file -c mono -f /dev/stdin

And then I have an old nice E4000 with a wider frequency range:
~ # rtl_test
Found 1 device(s):
0: Generic RTL2832U (e.g. hama nano)
Using device 0: Generic RTL2832U (e.g. hama nano)
Found Elonics E4000 tuner
Supported gain values (14): -1.0 1.5 4.0 6.5 9.0 11.5 14.0 16.5 19.0 21.5 24.0 29.0 34.0 42.0

That one has a few ppm error too, but the larger frequency range is great, I rebuild it mounting the PCB in a dycast box.
E4000 tuner is maybe harder to find these days, no TCXO.

So it depends.
For testing I just always use a TCXO one.

Very nice things to have, one in use to receive data from a cheap 433 MHz wireless weather sensor mounted outside under the garden table
uses 'rtl_433' software.
Planes with 'dump1090'.

http://panteltje.com/panteltje/xpsa/index.html
Note the harmonic factor button, say you have 144 MHz,
just press it to 2 and you see 288, 432, etc etc tells you a lot about your filtering
In the olden days in broadcasting we used to test the eurovision audio lines with 1000 Hz,
and then measure the amplitude of 2000, 3000, 4000, etc .. do the math and get distortion.
No scope in the world ... !
That also works for MHz..


Just scan the spectrum, last week I was searching for some interference, came from a HDMI cable...

 

[Jan Panteltje]

On a sunny day (Wed, 16 Oct 2019 19:49:34 -0000 (UTC)) it happened Cursitor
Doom <curd@notformail.com> wrote in <qo7s8e$4lg$3@dont-email.me>:

On Wed, 16 Oct 2019 16:35:58 +0000, Jan Panteltje wrote:

1500 W PUSSIES!!!
;-)

Found some good Linux laptops locally for sale..

Are you going to Rosmalin for the big electronics swap meet next March,
Jan?

No, I think you mean 'Rosmalen', that was in March this year.
Did not go there, is a ham radio market, I do have a callsign though.
https://amateurzender.nl/events/radiomarkt-rosmalen/

Already have enough stuff

 

[Jan Panteltje]

On a sunny day (Thu, 17 Oct 2019 04:38:03 -0000 (UTC)) it happened Jasen Betts
<jasen@xnet.co.nz> wrote in <qo8r7b$m2a$1@gonzo.revmaps.no-ip.org>:

On 2019-10-16, upsidedown@downunder.com <upsidedown@downunder.com> wrote:
On Wed, 16 Oct 2019 07:31:21 GMT, Jan Panteltje
pNaOnStPeAlMtje@yahoo.com> wrote:

LOL
not everybody is the same, I am fighting with software.
Real fun, my systems got attacked by one of the most evil ones, the well known Jan Panteltje.
I bought a 2400 W water boiler, for coffee that is.
Plugging it in did indeed boil 1.5 liter water in about 3 minutes, but it also caused a dip in the mains
that in turn caused my main PC reiserfs to see bad sectors,
Rescue failed.

2400 W is only 10 A steady state i.e. 24 ohm resistance.

Unfortunately the cold resistance is quite low, until the resistor
reaches nominal operating temperature, so the cold start current can
be much larger than 10 A.

It could be as low as 22 ohms when cold. but I can't see an xtra half-amp
making a big difference.

Indeed, I measred the change for an electric heater spiral,
not really much betwen cold and glowing red.

It is different for filament (Edison type) bulbs, that maybe be a factor 10.

 

[Cursitor Doom]

On Thu, 17 Oct 2019 07:31:23 +0000, Jan Panteltje wrote:

> Again, do you have a cellphone?

Yes, of course. HATE the damn thing, but there's no avoiding them. What
are you driving at, dear boy?



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[Cursitor Doom]

On Thu, 17 Oct 2019 06:46:42 +0000, Jan Panteltje wrote:

No, I think you mean 'Rosmalen', that was in March this year.
Did not go there, is a ham radio market, I do have a callsign though.
https://amateurzender.nl/events/radiomarkt-rosmalen/

Already have enough stuff

Same here! Far too much stuff in fact. Well, if you're not too far away
why not pop over and meet up at the next one? And don't worry - I'm not
gay!
:-D



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