Are Your Ham Radios LEGAL? Test Them Yourself!
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- Опубликовано: 12 июн 2024
- How do you know if your radio is compliant & legal. You can test your own ham or CB radios for spurious emissions, spectral purity, output power and more with a cheap TinySA spectrum analyzer from Amazon! I even use it to check out other RF transmitters in my area.
Equipment used in this video:
(Amazon affiliate links)
TinySA Ultra 👉 geni.us/AvGQJ
40dB Attenuator (SMA) 👉 geni.us/heuQgnJ
Universal Adapter Kit 👉 geni.us/goeu
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TinySA 100 KHz to 960 MHz 👉 geni.us/PfHm7
⏱️Chapters⏱️
0:00 Test Your Radios with the TinySA
1:16 VERY IMPORTANT THINGS TO KNOW!
4:41 Measuring Output Power
7:42 Measuring Harmonics & Spurious Emissions
12:26 Looking at the RF Spectrum
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(Amazon affiliate links)
TinySA Ultra 👉 geni.us/AvGQJ
40dB Attenuator (SMA) 👉 geni.us/heuQgnJ
Universal Adapter Kit 👉 geni.us/goeu
----
TinySA 100 KHz to 960 MHz 👉 geni.us/PfHm7
Wonderfully clear explanation of how to test radios with the TinySA, nicely done!
Thank you very much!
On the TinySA's. "This one is a little bit more expensive..." Yeah, a little bit! 😂 Good video. I've been thinking about picking up one of these units.
About three times the price yeah!
Great demonstration of the TinySA! - Cheers!
Thank you! Cheers!
Keep in mind that while the Tiny SAs are very good and well worth buying, they are not really a lab quality instrument. They're great for comparative and illustrative purposes but aren't always reliable for absolute measurements. I see quite a bit of variation between the Tiny SA and my Siglent instrument.
And the other issue is that they are suitable for static tests like harmonics. The TinySa wont have enough dynamic range to test transmit IMD and because its a sweeping analyzer will miss critical things like ALC overshoot and keying transient spikes. Its wishful think that such a simple toy could do a complete suite of measurement tests. A better starting point would be Siglent or Rigol or even a high DDC receiver for measuring transmitter and amplifier IMD. Linrad from SM5BSZ used on a good DDC SDR makes a much better HF spectrum analyzer and has got more sensible test options that is meaningful rather than being wishful!
Awesome, super helpful! Exactly what I needed as I wanted to test all my HT's. The calculations also helped as I didn't know how to figure all that out, too.👍🤠
Glad it was helpful!
Thanks for this video.
Thanks for watching!
You could use an “RF Power Snitch” to double check if the power level is safe.
Interesting video. I have the TinySA Ultra and just love it. But, for you....jumper cables ! WOW, way too much of a load on those SMA connectors. The TinySA comes with cables, you should use them.
Barry, KU3X
Thanks for sharing
Great content and very helpful for someone interested in the hobby. I realize this is a very basic question and more related to test and measurement practice than this measurement in particular, but would it be possible to precisely measure the calibration of the attenuator chain first / why would that be more difficult than it’s worth etc. Perhaps it’s neccessary to just have much higher end test equipment to get that accuracy etc?
I do have a HP service monitor that I've measured those attenuators in the video. They are within +/- 0.5dB of accuracy... even better for the big one with the heatsink... I think I measured it on 146 MHz at 20.13dB.
But yes - good point, you can get some cheap attenuators that might be rubbish and not the correct spec.
Luckily hams are never pedantic and are always polite in the comments. No one will ever say anything about the -16.02
😂 that’s right, very lucky!
It's the FCC's fault. If the limit had been specified as 25.11886 uW then it would have been 'really' close to -16.0 dBm 🙂.
Good meaty stuff. :bow: Now at first blush I would have assumed you had a nice shielded connection between the radio and the TinySA yet you still picked up the transmission from another radio in the shack (it did seem to be rather weak). Any idea how that signal snuck in? Just goes to show you - testing can be hard!
Yeah that transmitter was literally 3 feet away.. there will always be a bit of leakage of signal in at those sort of distances.
I use a nanovna to test the attenuator's actual attenuation. Since they won't be exactly 20 or 40db.
It would be a good experiment to go to a high up location and attempt to pickup actual 2nd harmonics transmissions of hams using a popular repeater. Using an sdr receiver and an antenna tuned to 288Mhz-296Mhz. From my qth I've not seen anything, but its milliwatts line of sight and I'm not at a high elevation.
The attenuation won’t be completely flat over its entire range, although my amphenol attenuators are only +/- 0.5dB within spec over the entire DC-3 GHz range.
Hayden,
Thanks for the video.
One thing I've always struggled with is dB's, I just can't get my head around them!
Am I just thick or something?
I've never really found a decent explanation as to how dB relates to power gain or loss
in a real-world situation, the mathematics just make my eyes glaze over.
Hey Mike,
I had planned on a video explaining a similar sort of topic - hopefully I’ll get to that soon
@@HamRadioDX Cheers, Hayden, that would be something to look forward to.
Hayden, I noticed the 50w attenuator has Type N connectors. How much would using UHF connectors affect the measurements, especially on the 2nd and 3rd harmonics? Or even if the fundamental was 70cm?
Interesting question - I wouldn’t use PL-259/SO239 connectors at UHF frequencies in this kind of testing - due to the inconsistent impedance above 100 MHz.. which they are commonly rated for - even though “up to 300 MHz” is also quoted.
At 2m I wouldn’t expected to see any major issues…
@@HamRadioDX Your assignment, should you decide to accept it, is compare measurements with UHF connectors and Type N....
@HamRadioDX Thanks for the reminder to use N type connectors for UHF frequencies. That (along with the need for the proper attenuation) should get a bit more air time from some other Hamtubers.
I have a 20 watt handheld Radio by Leixen and want to test spectral purity. What value of attenuation would you say to use with my TinySA Ultra?
20 Watts is 43dBm. So you'd probably be best to invest in at least 50dB of attenuation to be safe. Perhaps join two attenuators together such as I did
Where did you get the 16.02db number at? I always see 40db or 43db.
-16.02 dBm is 25uw (microwatts) and is mentioned in the fcc regulations about reducing between 25uw and 10uw. So that needs to be equated within the maths for determining attenuation. Cheers
Screen and shape looks like the NanoVNA. Forgive my ignorance. Are the two related? 73 de Jon, VU2JO
I think so? Pretty sure they are made by the same company
@@HamRadioDX Thank you. Yet to get hold of either of them.
@@johnsonstechworld You will not regret getting a decent nanoVNA, there is so much you can do with it.
Just be aware of the cheap copies and you'll be fine.
@@mikeZL3XD7029 Thank you. 73
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DON'T RISK IT????? Clearly click bait. No one is going to chase a 5W radio with slightly dirty harmonics and you know that.
Settle down Karen.
No one own the airwaves. Legal or not is your opinion.
Yes boss
These Walkie talkies are low powered signals under 5 watts, so if the IMD is not too good the the damage caused by the transmitter will be minimal. These walkie talkies are intended for the amateur radio market and as long as those signals stay within the amateur radio bands you be ok , you want be hunted down. LOL Serious problem only occur when you running high powered amps and transceivers with crappy IMD specs. The minimal specs by the FCC for manufactured transceivers, transmitters, and amplifiers is -50 db below the fundamental frequency. If this was really enforced 95% of all the Chinese, and a lot of Icom , kenwood, yaesu equipment would not be imported. Now commercial equipment the FCC is tight on customs cause this is where the money is.