Re: It is fun to be stupid!
I would have tried the procedure a 24th time ............... just to be sure.
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Re: Observing a low frequency signal using an up converter
Hello Isidro,
What you say about using the normal IF port as input is true for the
minicircuits mixers such as the SBL1. But there are many other
mixers
that can work right down to DC. Especially many of the IC mixers.
73 Ken g8beq
On 21/12/2022 19:50, Isidro Berniol
wrote:
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Show quoted text
Hi,
This Description misses some important things.
Thie mixer IF port is used as input. If you select
the right mixer the input can be DC coupled, allowing
measurement down to very low frequencies.
Also it can make sense to use a higher IF then
10MHz for easy filter implementation.
To have a good level translation use a 3dB
attenuator on all thee ports.
Mini Circuits high level mixers work great for
this purpose.
All the Best,
Isidro
herunterladen
Am 21. Dez. 2022, um 16:14, "Kenneth
Greenough via "
< talktalk.net@groups.io
target=_blank> [email protected]> schrieb:
Hello Larry,
An up converter is basically a mixer,double balanced being
best for the
purpose and an oscillator.? For stability the oscillator will
likely be
a crystal controlled one.? Say the osc' is on 10 MHz and fed
into one
port of the mixer, low frequency signals you wish to monitor
are fed
into the signal input of the mixer. The output of the mixer is
the
10 MHz osc, very reduced due to the cancellation balance of
the
mixer and the low frequency signals appear as modulation [
both
sidebands] of the 10 MHz. If you feed the output to the SA you
can
monitor the modulation. in other words you have up converted
the
low frequency signals.?? A down converter works in exactly the
same
way to monitor higher frequencies which are above the upper
limit of the SA.
?Ken g8beq?
On 21/12/2022 14:14, Lawrance A.
Schneider wrote:
If ignorance
were bliss, I'd be in heaven. ?I'm not there yet but I am
ignorant.
What is an 'up converter'? ?Yes, I understand the words but
that does not tell me what it is nor how it works.
Thanks, ? ? ? ? ? larry
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Re: Observing a low frequency signal using an up converter
Hello Larry,
It's an unfortunate fact that most times you already need to have
accurate
test gear to check anything else.
73 Ken g8beq
On 21/12/2022 16:48, Lawrance A.
Schneider wrote:
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Show quoted text
On Wed, Dec 21, 2022 at 11:13 AM, John Cunliffe W7ZQ wrote:
So a 0dbm signal in equals a 0dbm signal out and a
-100 dbm signal in equals a -100dbm signal out. It tracks pretty
good within +- 1-2db above 30khz.
First, thank you both (Kenneth Greenough &??John Cunliffe W7ZQ).
How are you sure the dbm is equivalent to dbm out? ?
larry
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Re: Observing a low frequency signal using an up converter
Hello John,
I realise that my description was very basic and could benefit from
filters, amplifiers etc.
For anyone wanting to just look at audio frequencies the oscillator
could be on 10.7 MHz
and the output of the mixer could be put through a crystal filter
from an ex PMR radio
etc. This could eliminate the osc' feedthrough and remove the
unwanted sideband.
A suitable amplifier could be set to give the same level output as
the audio input and
then attenuated to suit the SA.? Although the shape of the filters
pass band would have
some effect.
73 Ken g8beq
On 21/12/2022 16:13, John Cunliffe W7ZQ
wrote:
toggle quoted message
Show quoted text
Thanks Kenneth,
Nice descriptions of the fundamental. This particular up converter
uses an external 10Mhz oscillator that ideally should be
synchronized to the spectrum analyzer for best accuracy.
It takes the low frequency input signal between about 10Khz and 2
Mhz and mixes it with the external source. It then applies some
basic filtering and level adjustments and then outputs a signal
above 10Mhz that mirrors the input signal in amplitude. So a 0dbm
signal in equals a 0dbm signal out and a -100 dbm signal in equals
a -100dbm signal out. It tracks pretty good within +- 1-2db above
30khz. Below that the sensitivity / dynamic range fails but is it
still usable.
I use the 10Mhz cal output of the tinySA as the external
oscillator. The signal as is, is too low so I added what I
believed to be a 20db amplifier but it turns out is actually close
to 30db on 10Mhz. That puts the 10Mhz signal right around 0dbm,
perfect for the box and since it is derived from the internal
clock of the tiny it is naturally synchronized to it.
Using the up converter I can now observe low frequency signals in
the 50-150khz range (my interest) using the full dynamic range of
the tinySA . The specs say it works up to 2Mhz but I have not
tested it there.? Eric made a nice video about the performance of
the tinySA on lower frequencies. This up converter gets around
some of the performance issues.
John
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Re: Observing a low frequency signal using an up converter
To find the perfect LO level for this application use the IF input of the mixer with a signal at the level limit of the mixer. Then apply the LO signal at the nominal level.
Now variate the input in 1dB steps and measure the output.
When you reach the 1dB compression point vary the LO level to see if it has an effect. If so lower the input level.
Note the minimum LO level needed and the maximal allowable LO level for the mixer. If you select a level 17dBm mixer from Mini Circuits the perfect LO power is 20dBm if you use a 3dB pad at the LO input.
A usual value for the level loss would be? 6 to 8 dB plus the loss of the 3dB pads.
All the Best,
Isidro
herunterladen
Am 21. Dez. 2022, um 20:48, John Cunliffe W7ZQ < n2nep@...> schrieb:
Lawrence,
No it is the output directly from the box. The amplifier I am using is for the 10Mhz cal out signal from the tinySA that is at about -30dbm and thus to small for the input of the box. The box needs to have ~ 0 to +10dbm signal at the external 10Mhz clock input.With the external clock input at 0dbm my up converter directly tracks the input signal.
John
|
Re: Observing a low frequency signal using an up converter
Hi,
This Description misses some important things.
Thie mixer IF port is used as input. If you select the right mixer the input can be DC coupled, allowing measurement down to very low frequencies.
Also it can make sense to use a higher IF then 10MHz for easy filter implementation.
To have a good level translation use a 3dB attenuator on all thee ports.
Mini Circuits high level mixers work great for this purpose.
All the Best,
Isidro
herunterladen
toggle quoted message
Show quoted text
Hello Larry,
An up converter is basically a mixer,double balanced being best for the
purpose and an oscillator.? For stability the oscillator will likely be
a crystal controlled one.? Say the osc' is on 10 MHz and fed into one
port of the mixer, low frequency signals you wish to monitor are fed
into the signal input of the mixer. The output of the mixer is the
10 MHz osc, very reduced due to the cancellation balance of the
mixer and the low frequency signals appear as modulation [ both
sidebands] of the 10 MHz. If you feed the output to the SA you can
monitor the modulation. in other words you have up converted the
low frequency signals.?? A down converter works in exactly the same
way to monitor higher frequencies which are above the upper limit of the SA.
?Ken g8beq?
On 21/12/2022 14:14, Lawrance A. Schneider wrote:
If ignorance were bliss, I'd be in heaven. ?I'm not there yet but I am ignorant.
What is an 'up converter'? ?Yes, I understand the words but that does not tell me what it is nor how it works.
Thanks, ? ? ? ? ? larry
|
Re: Observing a low frequency signal using an up converter
Lawrence,
No it is the output directly from the box. The amplifier I am using is for the 10Mhz cal out signal from the tinySA that is at about -30dbm and thus to small for the input of the box. The box needs to have ~ 0 to +10dbm signal at the external 10Mhz clock input.With the external clock input at 0dbm my up converter directly tracks the input signal.
John
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Re: tinySA branch 'V4.3' renamed to 'main'
On Wed, Dec 21, 2022 at 01:55 PM, Erik Kaashoek wrote:
Bumped version to v1.4
Hello tinySA hackers,
?
If you clone directly from Erik's GitHub repository, you're ready to go locally - but to participate in the development process and create PRs, you need to do a bit more.
?
If you forked to GitHub first and cloned from that (up-to-sync) fork (as I did), you'll need to get the new tag because it won't sync automatically.
?
? ? git tag | grep v1
? ? ? ? v1.0
? ? ? ? v1.1
? ? ? ? v1.2
? ? ? ? v1.3
Perform this tag sync with:
? ? git fetch --tags https://github.com/erikkaashoek/tinySA.git
Now the latest tag is available on your local repo:
? ? git tag | grep v1
? ? ? ? v1.0
? ? ? ? v1.1
? ? ? ? v1.2
? ? ? ? v1.3
? ? ? ? v1.4
Another options would be to define two uptreams in your local git repository, one pointing to??and the other to your own GitHub repository.? Clone your repository, in my case? ? ? git clone <your repository> Add a 2nd upstream remote, e.g named erikkaashoek: ? ? git remote add erikkaashoek https://github.com/erikkaashoek/tinySA.git ? ? git fetch erikkaashoek Now create a branch, e.g. also with the name erikkaashoek ? ? git branch erikkaashoek and associate it with the main branch of Erik's repo (the remote upstream erikkaashoek) ? ? git branch -u erikkaashoek/main erikkaashoek
? ? ? ? Branch 'erikkaashoek' set up to track remote branch 'main' from 'erikkaashoek'.
Then you have a read-only branch erikkaashoek linked to the original from which you can sync your main branch via e.g.? ? ? git checkout main ? ? git rebase erikkaashoek Work on main, create branches for features from there, work, test, upload to the tinySA, etc. Push the feature branch (to your GH repository) and create a PR from your GH repo. Martin
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We are at the point where colleges and universities could require engineering students enrolled in a related course to purchase a TinySA, just like a textbook. I may be old, but I do remember the days when textbooks were printed on paper and purchased in a bookstore rather than as PDF files! --
Ed, K0KC
?
k0kc@...
http://k0kc.us/
|
Just blows my mind what we can do with just a couple hundred dollars. I'm 75 and remember in college lab manually measuring hundreds of points and plotting on graph paper with equipment you could only dream of using let alone own! Something like the TinySa would have been pie in the sky science fiction! ?
Attached, please find the response curve for a low pass filter generated by my TinySA Ultra and my new noise source. The curve was generated using TinySA-App.
Thanks again to all who helped me understand how to properly use the noise source with the TinySA Ultra!
--
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Re: Observing a low frequency signal using an up converter
On Wed, Dec 21, 2022 at 11:57 AM, John Cunliffe W7ZQ wrote:
a -50dbm signal the output equals a -50dbm
Thank you for your prompt reply. I understand comparing. ?What I'm wondering about are you using an external amplifier or is there circuitry within the?BG7TBL that assures equivalency. ?I'm about to view a few videos that may tell me more. Thanks, ? ? ? ? ?larry
|
Attached, please find the response curve for a low pass filter generated by my TinySA Ultra and my new noise source. The curve was generated using TinySA-App.
Thanks again to all who helped me understand how to properly use the noise source with the TinySA Ultra!
Ed, K0KC
k0kc@...
http://k0kc.us/ --
Ed, K0KC
?
k0kc@...
http://k0kc.us/
|
Re: Observing a low frequency signal using an up converter
Lawrance,
Because for the tests I feed it a calibrated level from my calibrated HP signal generator and read the output with the TinySA. If I feed it a -50dbm signal the output equals a -50dbm signal on the tinySA (and on my HP spectrum analyzer I use to double check), and when I feed a -100dbm signal, the tinSA reads a -100dbm signal. I did those tests between 0dbm and -120dbm and it tracks well within the specs of the tinySA.
John
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Re: Observing a low frequency signal using an up converter
On Wed, Dec 21, 2022 at 11:13 AM, John Cunliffe W7ZQ wrote:
So a 0dbm signal in equals a 0dbm signal out and a -100 dbm signal in equals a -100dbm signal out. It tracks pretty good within +- 1-2db above 30khz.
First, thank you both (Kenneth Greenough &?? John Cunliffe W7ZQ). How are you sure the dbm is equivalent to dbm out? ? larry
|
Re: Observing a low frequency signal using an up converter
Thanks Kenneth,
Nice descriptions of the fundamental. This particular up converter uses an external 10Mhz oscillator that ideally should be synchronized to the spectrum analyzer for best accuracy.
It takes the low frequency input signal between about 10Khz and 2 Mhz and mixes it with the external source. It then applies some basic filtering and level adjustments and then outputs a signal above 10Mhz that mirrors the input signal in amplitude. So a 0dbm signal in equals a 0dbm signal out and a -100 dbm signal in equals a -100dbm signal out. It tracks pretty good within +- 1-2db above 30khz. Below that the sensitivity / dynamic range fails but is it still usable.
I use the 10Mhz cal output of the tinySA as the external oscillator. The signal as is, is too low so I added what I believed to be a 20db amplifier but it turns out is actually close to 30db on 10Mhz. That puts the 10Mhz signal right around 0dbm, perfect for the box and since it is derived from the internal clock of the tiny it is naturally synchronized to it.
Using the up converter I can now observe low frequency signals in the 50-150khz range (my interest) using the full dynamic range of the tinySA . The specs say it works up to 2Mhz but I have not tested it there.? Eric made a nice video about the performance of the tinySA on lower frequencies. This up converter gets around some of the performance issues.
John
|
Re: Measuring 10GHz on the Ultra
Mike, I agree with all of Jim's suggestions and have only one to add of my own:
Try googling "MA Gunnplexer" to find more "threads to pull" for info on the subject of devices of this type. I don't think that's actually what you have, but the release of those devices in the 1970's created a lot of interest in the subject and might give you some ideas about what you do have.
My 1970s experiences involved similar devices from MA in the form of oscillator, detector and antenna products from their product line, but I was not using the gunnplexer, and all of this was a very long time ago.
I found R&L showing stock of the Ultra last night and ordered mine. I hope to receive it soon. Note that I am NOT one of the people reporting success in displaying 10ghz output - I had only expressed interest in the subject myself.
Mike, feel free to contact me directly again (as you originally did), but I'm probably not going to be much help.?I suspect discussion of the device itself (as opposed to use of the Ultra to test it) is not exactly on topic here.
happy holidays to all,
M
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Re: Observing a low frequency signal using an up converter
Hello Larry,
An up converter is basically a mixer,double balanced being best for
the
purpose and an oscillator.? For stability the oscillator will likely
be
a crystal controlled one.? Say the osc' is on 10 MHz and fed into
one
port of the mixer, low frequency signals you wish to monitor are fed
into the signal input of the mixer. The output of the mixer is the
10 MHz osc, very reduced due to the cancellation balance of the
mixer and the low frequency signals appear as modulation [ both
sidebands] of the 10 MHz. If you feed the output to the SA you can
monitor the modulation. in other words you have up converted the
low frequency signals.?? A down converter works in exactly the same
way to monitor higher frequencies which are above the upper limit of
the SA.
?Ken g8beq?
On 21/12/2022 14:14, Lawrance A.
Schneider wrote:
toggle quoted message
Show quoted text
If ignorance were bliss, I'd be in heaven. ?I'm not there yet but
I am ignorant.
What is an 'up converter'? ?Yes, I understand the words but that
does not tell me what it is nor how it works.
Thanks, ? ? ? ? ? larry
|
Re: New ULTRA FW release: Added frequency to BIG number display
This helps. Bug found and will be solved in next release --
For more info on the tinySA go to https://tinysa.org/wiki/
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Re: New ULTRA FW release: Added frequency to BIG number display
I have this problem too.
Mirek
Dne 21.12.2022 v 15:33 Erik Kaashoek
napsal(a):
toggle quoted message
Show quoted text
Can you post a screen capture or photo?
I can't replicate
--
For more info on the tinySA go to
|
Re: New ULTRA FW release: Added frequency to BIG number display
Can you post a screen capture or photo? I can't replicate --
For more info on the tinySA go to https://tinysa.org/wiki/
|
John Cunliffe W7ZQ
Ho-Ro
