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Re: Output impedance of RF sinewave generator (Tiny Ultra)
Please do not modify the tinySA HW, you will make it worse.
The output impedance is roughly 50 ohm but for best impedance matching you can consider adding a 6 dB external attenuator.
I never do this myself as the output impedance without external attenuator is good enough for me.
Keep in mind the output level is not adjusted when doing calibration, by default is uses the factory settings. There are several settings you can adjust to improve the output level accuracy if needed.
Have a look at the wiki.
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Designer of the tinySA For more info go to |
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Re: WinSpectrum III spectrum analyzer application designed for Windows users working with Tiny SA Ultra+
A 64 bits update is now available. Additionally, following your suggestion Stephen, a 32-bit version targeting .NET Framework 2.0 has been added for better compatibility with older systems. Feel free to download the one that best fits your setup.
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Re: Output impedance of RF sinewave generator (Tiny Ultra)
That means that the output is low impedance, i.e. not 50 ohms? Could I insert a resistor at an appropriate place behind the mux, in the signal path from the generator? On Thu, 20 Mar 2025 21:43:59 +0100, Erik Kaashoek via groups.io <erik@...> wrote:
-- Erstellt mit Operas E-Mail-Modul: |
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Output impedance of RF sinewave generator (Tiny Ultra)
Today, as I was going to measure the frequency (sensitivity) plot of a 500 MHz Keysight oscilloscope, I found that the measured amplitude was going to increase by approx. 6 dB from approx. 150 to 300 MHz, and then drops down somewhat. Despite a direct connection using SMA-BNC adapter and direct coupling without coax cable and a 50 ohms scope input. At any case: the behaviour got (expectedly) a bit worse when I selected a high impedance input while using a BNC T-connector for termination with a BNC 50 ohms termination resistor. After doing some experiments, I discovered this: with the latter configuration I also switched the internal 50 ohms to active state (resulting termination: 25 ohms). It was a nice surprise that the amplitude shown on the screen was really constant over the whole range that was used (up to 500 MHz), while the amplitude under 150 MHz was fairly the same as in the case of a single 50 ohms termination. The question: what about the output impedance of the generator?? Rob |
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Re: What accessories do I need for a TinySA Ultra?
开云体育Ok, i got it. All references when not given are 0db = 1w Thanks Sent from my Verizon, Samsung Galaxy smartphone -------- Original message -------- From: "W0LEV via groups.io" <davearea51a@...> Date: 3/20/25 2:39 PM (GMT-05:00) Subject: Re: [tinysa] What accessories do I need for a TinySA Ultra? QUOTE:? So, the TinySA is probably relative to mW or -10db down from 0.001W = 0.1mW or 0.0001W ? ** 1 Watt = 1.00.... Watts = 0 dBW = +30 dBm 1 milliwatt = 0.001 Watts = 0 dBm = -30 dBW 0.10 milliwatt = 0.0001 Watts = -10 dBm = -40 dBW 0.01 milliwatts = 0.00001 Watts = -20 dBm = - 50 dBW 0.001 milliwatts = 0.000001 Watts = -30 dBm = -60 dBW All powers of 10 which you learned in Jr. High School. BTW:? dB directly adds and substracts.? Dave - W?LEV On Thu, Mar 20, 2025 at 5:52?PM sdegroff via <sdegroff=[email protected]> wrote:
-- Dave - W?LEV |
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Re: What accessories do I need for a TinySA Ultra?
On Thu, Mar 20, 2025 at 10:29 AM, sdegroff wrote:
The tinySA measures absolute power in a 50 ohm load and can display in various units such as dBm, volt and watt
dBm is log of watt
dB is relative.
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Designer of the tinySA For more info go to |
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Re: What accessories do I need for a TinySA Ultra?
QUOTE:? So, the TinySA is probably relative to mW or -10db down from 0.001W = 0.1mW or 0.0001W ? ** 1 Watt = 1.00.... Watts = 0 dBW = +30 dBm 1 milliwatt = 0.001 Watts = 0 dBm = -30 dBW 0.10 milliwatt = 0.0001 Watts = -10 dBm = -40 dBW 0.01 milliwatts = 0.00001 Watts = -20 dBm = - 50 dBW 0.001 milliwatts = 0.000001 Watts = -30 dBm = -60 dBW All powers of 10 which you learned in Jr. High School. BTW:? dB directly adds and substracts.? Dave - W?LEV On Thu, Mar 20, 2025 at 5:52?PM sdegroff via <sdegroff=[email protected]> wrote:
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Dave - W?LEV |
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Re: What accessories do I need for a TinySA Ultra?
开云体育So, the TinySA is probably relative to mW or -10db down from 0.001W = 0.1mW or 0.0001W ? Sent from my Verizon, Samsung Galaxy smartphone -------- Original message -------- From: "W0LEV via groups.io" <davearea51a@...> Date: 3/20/25 1:36 PM (GMT-05:00) Subject: Re: [tinysa] What accessories do I need for a TinySA Ultra? The standard of power measurement for most things RF these days is the: ??? Watt or dBW ??? Milliwatt or dBm This assumes measurements are made in a non-reactive (resistive only) 50-ohm system.? That leaves our 75-ohm TV associates in the dark.? So be it.? The fast majority of the RF and ?W industries uses the 50-ohm standard. With these abbreviations, please note the PROPER capitalizations as well!!!? W is after Mr. Watt.? m is just a standard abbreviation for a power of 10 or 0.001. Dave - W?LEV? On Thu, Mar 20, 2025 at 5:30?PM sdegroff via <sdegroff=[email protected]> wrote:
-- Dave - W?LEV |
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Re: What accessories do I need for a TinySA Ultra?
The standard of power measurement for most things RF these days is the: ??? Watt or dBW ??? Milliwatt or dBm This assumes measurements are made in a non-reactive (resistive only) 50-ohm system.? That leaves our 75-ohm TV associates in the dark.? So be it.? The fast majority of the RF and ?W industries uses the 50-ohm standard. With these abbreviations, please note the PROPER capitalizations as well!!!? W is after Mr. Watt.? m is just a standard abbreviation for a power of 10 or 0.001. Dave - W?LEV? On Thu, Mar 20, 2025 at 5:30?PM sdegroff via <sdegroff=[email protected]> wrote:
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Dave - W?LEV |
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Re: What accessories do I need for a TinySA Ultra?
Quick dumb question.
Since db is a relative measurement of power, in this case,? and I'm not sure to what standard that is, what units are tinySA db relative to?
mW, W, uW or voltage or current level ratio(s)?
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ie:in the case of 5w output and 1w input would be a gain of:
10log10(POUT/PIN)=10log10(5)≈7?dB
I would be thinking it is a maximum input voltage level like approx 3.5v as the new mos chip level inputs?
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Thanks
Stan W8SRD
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Re: What accessories do I need for a TinySA Ultra?
On Thu, Mar 20, 2025 at 05:38 AM, <asron87@...> wrote:
I should leave a 10db attenuator connected and then the antenna connected to that? Yes, only after doing a full range sweep and confirming there are no strong signals (above -20 dBm) you may remove the 10 dB attenuator if needed for the measurement.
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Designer of the tinySA For more info go to |
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Re: What accessories do I need for a TinySA Ultra?
Oh and can you use metal dust caps on the connection not being used when using a TinySA or NanoVNA?
I have these nickle plated ones for equipment but was wondering if they would cause interference. ?
Or would I be better off sticking with Rubber Caps? I have these and would recommend them to anyone interested. They are cheap and pretty durable.? |
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Re: What accessories do I need for a TinySA Ultra?
Those will work but can find much cheaper on Aliexpress.?
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-- Don ? K5ZRQ |
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Re: What accessories do I need for a TinySA Ultra?
If I'm understanding you correctly I should leave a 10db attenuator connected and then the antenna connected to that?
Like this Constant Attenuator (10db)? (Or do you recommend a different one?)
And then a DC block for when measuring with any DC offset. (I'm not sure what that means yet but I'll look into it) Does this DC block work? (Or go with something different?) I swear I tried looking all of this up before asking here but I ran into a lot of misinformation so I'm glad I asked. I appreciate you taking the time to answer my questions. |
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Re: WinSpectrum III spectrum analyzer application designed for Windows users working with Tiny SA Ultra+
I am a reader, not a sender of messages, usually.
However the Windows application sounds (is sound the correct word for a written message?) very useful. What might make it even more useful is to run it on XP (howls of laughter …..), or at least Win7. I have a large pile of old notebooks and laptops which cannot be used, as much of the useful software will not run on such an ancient platform. I am sure that we all have “old” laptops in a cupboard somewhere. Using this application on an otherwise redundant device also would not take up so much workbench space and be much more portable and cheaper. Heaven forbid if one eventually managed to fit the SA into a floppy disk slot (with the two sma connectors accessible). Stephen Laurence. G7PSZ |
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Re: What accessories do I need for a TinySA Ultra?
On Wed, Mar 19, 2025 at 10:22 PM, <asron87@...> wrote:
Erik.... are you really the guy that made these?Yes That's awesome to be a beginner and get an answer from the creator. So thank you for that.DC block for when measuring with any DC offset and at least 10, 20 and 30 dB 2 Watt attenuators. Leave the 10 dB always on the input and it will be safe.
When trying to probe (low or high impedance) circuits a active RF probe is useful, see:
This probe also acts as a rather good protection.
?No, either a 10 dB attenuator or the active probe will do. And please do not connect the tinySA directly to the transmitter output but use either a high power attenuator or a home made power sampler. These are easy to make for below 500 MHz
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Designer of the tinySA For more info go to |
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Re: What accessories do I need for a TinySA Ultra?
Oh and can someone link to a 0-1Ghz LNA worth buying. And also a link for a backup 50ohm calibration kit? Or how do I test if i buy one to see if its 50ohms?? Links to attenuator worth buying? And can someone explain the VLM-33W-2W-S+ part to me? That ones going way over my head. |
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Re: What accessories do I need for a TinySA Ultra?
Erik.... are you really the guy that made these? That's awesome to be a beginner and get an answer from the creator. So thank you for that.
What accessories would you recommend? Is a VLM-33W-2W-S+ something I should look into getting? Here's a link to what was mentioned. https://www.minicircuits.com/WebStore/dashboard.html?model=VLM-33W-2W-S%2B&srsltid=AfmBOorOt7cyUDyF3pdAGc_SH-yOIsH96Bhd95iHfDJP0W3xAr0t1ozV ?
If anyone has any other recommendations can you post some links to them so I don't mess up ordering? I think I already ordered some wrong parts lol |
Xavier Junqué i de Fortuny
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