#557b
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- เผยแพร่เมื่อ 1 ต.ค. 2024
- Episode 557b
Make sure you don't over power your TinySA. Check all frequencies and total power.
datasheet: maximum +10dBm input power either port
less than 15VDC offset
My recommendation: maximum 0dBm (1mW) input power
0VDC offset
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Both inputs of the tinySA are DC isolated. Don't go above 15 volt
Thanks
you now recommend 10 volts max?
@@IMSAIGuy I realize you're under no obligation but you should consider removing the comments interaction by "Francisco Braylen" and "Morgan Adriel" from this comment thread. The interaction is fake and used to promote a potential phishing application putting your viewers at risk. Cheers!
@@BreakingPintMedia thank you
What about using a DC block always in the input? Does it avoid any DC destructive levels ??
This was a great lesson. I am always amused as you consider costs as I do when getting new gear. Well, your power meter is an expensive bit of kit. Fall back to the Chinese alternatives? I need some product reviews for power meter choices.
I'll keep that 30db attenuator handy.
I was just checking the comments to see how many people were saying to use protection while practicing safe analyzing
Great. Have ever made a video about cheap (affordable) Power Sensors or Power Meters - if available at all?
I'd like to take a look at the spectrum near some commercial communication towers, like within 100 feet of them. I'd like to do it with the antenna that comes with the tinysa. Obviously I'll have no idea how much power the towers emit, but do you think I should put a pad between the antenna and tinysa? Could I get enough power to kill it just from the towers into the antenna?
depends on the power of the transmitter. 50,000 Watts will light a fluorescent 4' tube. You can always be cautious. start with a pad. start with the antenna not extended. if the power is low, remove the pad, if low extend the antenna. start 1000 ft away....
@@IMSAIGuy Wow. Didn't know that about the lightbulb LOL. 1000 ft away with a 20 pad sounds like a good start. Thanks!
Thank you, I learn something new from each of your videos, not just these devices - everything you've done here I know about.
- Should I be concerned about external electromagnetic interference? With the TinySA's closely spaced components there could be flashover. I'm admittedly ignorant in this realm, it just seems that with the necessarily non-conductive box, there could be a potential for damage while nearby a KV source, whether on or off. What do you (all) think?
Though not living near one, I often travel quite close to HV emanations, and while not too concerned because all are working fine, it brought up the question.
I'm no ham radio enthusiast, just a radar tech for the USAF. I've wanted a SA since I learned how to work with the HP 8566x. I like understanding what's happening around me, RF-wise...or maybe I'm just nosy.
@@IMSAIGuy I am interested in Bio-EMC. Is it safe with TinySA Ultra to point a handheld triangular (log periodic?) directional antenna at the mobile radio tower on the roof of the opposing street side, or will this already need an attenuator. (Yet I haven't bought the device yet.)
If you had 5 watts on that 30 db pad it would get very hot really quickly. lol
Is there a relatively cheap (sub $50 perhaps) way of measuring power with sufficient accuracy to ensure the SA will not be damaged?
there are some in the range of $25 that measure up to about +15dbm so would need attenuation. I'm not sure what the sensor is and what the frequency range would be.
I think most if not all are based on an analog devices chip that only goes to 500MHz but that might be enough.
I'd like to agree about using attenuators though out RF signal paths because they stabilize the (supposedly purely resistive) 50 Ohm path.
You will find 2 thru 4 dB attenuation blocks, at every stage, and indeed all the way thru an RF signal chain in professional Avionics = 1GHZ+ and 2KW power.
Attenuation "Pads" offer safe 50 Ohm ports for every next stage, and allow you to test sub-blocks if you DIY and connect aligned amplifiers.
You would not think so, but small Attenuation "Pads" are very often used at the beginning and end of Intermediate Frequency filters (ceramic 3-5 pole coaxial, SAW, Mechanical) because filter response varies wildly with miscellaneous input/output impedances to add reliabilty and ease alignment.
Can I just use a microwatt or microamp and milliwatt and watt analogue meter to check for power output? That in line with a resistor. Sorry I know nothing.
I hooked up my tiny SA ultra in sig gen mode to my 100w Kenwood to measure rx sens. Took all precautions it would not Tx. I then ordered a 40db 10 w attenuator for $Aud 40 on Ebay in case this ever happened, but , thanks to your video, I will use it on Rx also, thanks for posting, VK2FP/AG7VC
sounds good, just keep the RF down below 10W and not 100
Great video. I am going to order my tinySA now. Thanks for posting. 73 de KT1R Lou
I have designed a local oscillator circuit. I am trying to determine if my LO output is safe to measure with my TinySA. I do not have a power meter. For low frequencies, namely amateur HF bands, would terminating across a 50 ohm load and measuring RMS voltage through a 10x scope probe be a reasonable alternative for measuring power (P=Vrms^2/50)?
th-cam.com/video/bryrAUBNDj8/w-d-xo.htmlsi=_mE_hJl9o3aPqb3q
Could you miss power peaks due to low amount of sweep points available during overview of instrument's entire frequency band and not looking for details with a lower span?
If so, what would be a good rule of thumb frequency range per x sweep points?
yes that is a problem. you need to consider the freq range, resolution bandwidth, and number of points. many times I turn on hold max and let the instrument run for a long time to catch events
Which safety distance is enough to prevent damage to a TinySA Ultra, when I measure with a small (likely a directional) antenna through the air?
I don't own high power transmitters (professional HAM radio etc.), but pointing at an internal DECT or wifi antenna of home electronics (router, laptop etc.) to verify for Bio-EMC that it stays off (or at which frequency range it transmits) will be important. I occasionally adjust TV modulators in old game consoles etc. and possibly I may buy a small CB radio walkie-talkie. The strongest emitting things I own is likely a plasma globe and a violet ray (mini tesla coil, may be among 1 and worst case 10W? RF) those I certainly should not approach too close with the antenna. Which distance is safe and when will I strictly need attenuators?
Greetings...
TinySA Measurement Options, use with a inline Attenuation...
Measure : Channel Power ....
Can I ask what power sensor you are using? Is it CW, modulated, etc.? I’ve searched and searched the numbers on it and I cannot find any reference for PT2-1001 or 20065 power sensor. Thanks!
Excellent video, BTW! This is really for any SA, not just the Tiny.
th-cam.com/video/C2eVLkIK3aI/w-d-xo.htmlsi=rcPr_icL_Vly7xUw
th-cam.com/video/8i5-O_8AZyk/w-d-xo.htmlsi=6igMjfaCeuAbQ76K
th-cam.com/video/2NzuDoBWVLw/w-d-xo.htmlsi=dB0EX8PznDnquRoB
Is it worth just always using a 30dbm attenuation😊
Can we ("I") assume you used a Function Generator / Signal Generator here? BTW, I loved the video. I just bought the "Ultra" and these videos are especially helpful.
I think this signal was 70MHz square wave.
Hi, how many db are necessary for the SMA attenuator?
Thanks for the excellent advice !
Where would I find an affordable power meter like that or should I look at a different tester?
So, ignorant question for which I apologize in advance, but can I just run any potential input signal into an RF wattmeter that covers from say, 1mhz to 20ghz, before hooking it up to the tiny sa, which is what a I "think" I saw you do? Then if said wattmeter shows any power level > +10dbm then I would only connect the signal to the tiny sa through a suitable pad or step attenuator? I'm a newbie so apologies for anything I've said that isn't sensible :-) Thanks btw for sharing this video!
Yes, the TinySA will be damaged if any power above +10dBm (10mWatt) is applied. And I see a lot of people with damaged ones. This is true for most all spectrum analyzers. The newer TinySA models now come with a warning sticker on it. You also need to be careful hooking up sources to a power meter. The fancy power sensor I used in the video is only good to +23dBm. You need a good assortment of attenuators to do RF measurements
can i use it for a musical synthesizer?
no
4:40 Potentially saving a $50 SA by risking a not so cheap 20 GHz power probe - like when the LDMOS saves the fuse :)
it is a catch 22
I really like your videos and have this tiny sa. Now I have bout 5 attenuators for me to do some aligning on my cb base station. My question is how do you know the input and output of the attenuators when they are not marked ?
they work either direction
If I'm going to use the tiny sa and putting in 100 milliwatts it's for a vintage a cb walkie talkie what type of attenuator should I use. Still kind of learning about vintage electronics
100mW is +20dBm. you should use a 20dB attenuator.
@@IMSAIGuy awesome thank you so much that's what I was thinking but I wanted to be sure thanks 👍😃
Can you recommend a reliable attenuator and a source to purchase them?
yes, Alan, Pasternak, Weinschel, Midwest microwave, Narda to name a few
Very interesting. "Why did you not use a DB Block? If I am directly feeding my analyzer, I use a DB Block. If I am getting a signal off of an RF sampler, no DB Block is usually needed.
Barry G. Kery
I'm not familiar with the term 'DB Block'
@@IMSAIGuy Probably meant a DC current/voltage blocker, so only AC passes through.
Can you connect attenuators just as you like? Or are they directional. Just thought that the SMA-male connector often are input. If the internal resistor network is symmetric, I guess it doesn't matter.
they are symmetric usually
They are usually in that type of low power bullet attenuators. We used to have some 100 watt attenuators. My boss told me to always use one end for a two way radio, because the mfr made the output (20 or 30 dB) end increasingly smaller in power rating as the attenuation increased. If I remember, they had "INPUT" on only one end. These had radiator fins on them, so that might give you pause if you spot those. Most of the time we just used them as dummy loads unless doing FCC testing or the output of a PA.
Thank you!
great information..
Thanks
So a 15dB drop amp or 20dB pre-amp inline would kill it ?
remember the spec is dBm (dB milliwatt). so if you use a 20dB amp on a 0dBm signal you get +20dBm and yes that will kill it. If you use a -50dBm signal and 20dB gain then you have -30dBm. that is OK
Thanks for this!
agreed on the power sensor but unlike the tinySA a powersensor can be quite expensive so not available to you. Can you suggest a cheapish alternative to your power sensor?
Sorry I do not. You can use a dummy load (50 ohms) and use a fast oscilloscope to measure the voltage across the 50ohms to measure power. You can not use a multimeter as they will not measure fast AC. Above 100MHz things get harder to do without expensive equipment. If you don't have access to a power measurement, then start with a large attenuator. then step up until you are no more than 0dBm. You usually know the maximum power that the device you measure is capable of.
Im curious, is there a way to test the SA if you suspect its been damaged?
there is a self test in the menu
@@IMSAIGuy oh right on. Many thanks.
I say can you please make a tutorial video with tinysa ultra showing how to spot and reduce harmonics in an FM transmitter any power you have maybe 5w please
ok, I will do a video
@@IMSAIGuy I am a big fan of you and the channel .and a little question how I can go with ultra to 0dbm output with signal generator. What is external gain 0dbm.
@@ElectronicsShow sorry I do not understand your question
@@IMSAIGuy sorry I translate .I reform the question .in tinysa ultra how I could set the signal generator output to 0dbm .what is down written external gain 0db .I hope it's clearer now thanks
the external gain setting is used if you have an external amplifier attached. if you have 10dB amp attached then the signal will be 10dB bigger, so the tinysa external gain setting just adds 10dB to the number. it does not effect the actual signal coming from the tinysa.