011 Retevis RT85: A legal "Baofeng" replacement? Let's do the measurements

[@HB9BLA]

After many comments, I checked all rigs also with my Spectran V6 and it proved that the spike at 3GHz is from the Spectrum Analyzer. So the RT85 and the IC-705 are clean, the Baofengs not

[@LawpickingLocksmith]

When I was staying more than 3 months in Switzerland I purchased a used Yaesu handheld on Ricardo. Shortly after 2 officials from Bakom knocked at my door at my temporary home in the Ticino. I explained that after 3 months I was using APRS via the Sunrise mobile network. They had all copies of the Ricardo transactions and explained that if I had bought a Baofeng they would confiscate it unless I could prove that it was permanently disabled from transmitting. They tried to sell me a Swiss license on the spot. They also had copies of my ham license exam of 1976 and my certificate of technical leader made in 1980. So much for "Big Brother".

[@vincei4252]

Yikes.

[@HB9BLA]

That is strange! I did not know that the BAKOM acts without a problem report.

[@ManuOutdoor]

This is a super service of the Bakom! Didn‘t expect that they act so fast 😀

[@matthiasmartin1975]

Yeah, great, but if one of us has an actual problem with interference they won't move a finger.

[@einars899]

Very interesting! Your spectrum analyzer is a scanning (swept) instrument, not a real time analyzer . Try to narrow the sweep to the frequencies close to the transmitter frequency. Or even to the suspicious harmonic or mix frequency. It will not be realtime, but it will sweep faster, and thus let you have a peek at what's going on . It may also shift your birdies off so they disappear from where they fooled you. Also try to add a "barrel" or piece of coax in your stack of pads. There may be a resonance in your stack. If the picture change, there you are. And the spike moving in the opposite direction is in my eyes just as you say a sign of a mirror image. I cannot think of anything else. I have been postponing measurements of my handies for some time. But you kicked me in my behind. And if a realtime SA passes by in our offices, I will not let it out immediately. ;-)

[@HB9BLA]

Thanks for the tips. I have a real-time SA (Spectran V6) an will have a Look with it. Also some sort of resonance is an interesting hypothesis…

[@jamess1787]

Oh my! I didn't know you have a second, more specialized channel. Wow. Yay!

[@jamess1787]

Subbed!

[@HB9BLA]

Welcome aboard the channel!

[@What_I_Make]

Interesting, the 3.00GHz look like the aliasing of the spectrum analyser.

[@HB9BLA]

This could be. So far I never experienced anything like that. But maybe it is because of the level of the signal… I will check it tomorrow.

[@rjordans]

I agree, adding another attenuator could help, maybe also check if there is an enabled preamp in the front-end

[@HB9BLA]

Adding an additional 10dB reduced the effect, but it did not disappear. The pre-amp is disabled and I played with the internal attenuation. But so far it did not disappear :-(

[@FesixGermany]

I can confirm, my UV-5R puts out harmonics with 50dB attenuation at best case (70cm low power) and about 40dB worst (2m high power). I did not use that radio for transmitting for a long time since another ham gave me his old Kenwood TH-D7 for free which puts out harmonics with 60dB attenuation in the worst case.

[@HB9BLA]

Thank you for your confirmation. Mine had even less difference in the lower power modes :-( That is why i did not mention it.

[@tommihommi1]

I tested three which all were in this range as well

Kenwood TH-D7 for free? Wow. It's a great transceiver, only slighty beat by its successor, the TH-D72, by a little bit improved software and built-in serial adapter. To this day, I don't know of any other similarly equipped handheld transceiver on the market. Its terrible battery (NiCd with NiMH packs available from Germany) and its size was the reason why I went for TH-F7 as my daily driver and I keep the D7 for satellite work, portable and other scheduled activities. I made a barrel jack to XT-60 cable and it works great with 3S Li-Poly pack.

[@tonyhawk123]

The harmonics is just the spectrum analyser picking up on the Swiss accent. Nothing to worry about!

[@HB9BLA]

That would be a wonderful explanation! Because so far, I have not found the reason. But it seems to come from the analyzer, not the rigs. Which is good news :-)

[@richardcorfield9926]

Interesting technique. I have limited kit so used a dummy load with small pickup antenna nearby and another receiver to check harmonics.

[@HB9BLA]

That is also good. But it includes the effects of the two antennas. So you have to expect different results.

[@ManuOutdoor]

Herzlichen Dank für den super Beitrag! Super erklärt und gezeigt! Jetzt ist es klar warum ua. Die Baofeng Geräte verboten wurden! 73 von Hb9tia

[@HB9BLA]

Gern geschehen! Du siehst auch: Wer misst, misst (manchmal) Mist ;-)

[@tomekdziekonski7478]

I have tried to "import" Retevis RT85 to Switzerland, and it was captured by BAKOM 🙂They wrote me that they will test it, and depending on the results of these tests I will get the device or an invoice... Keep your fingers crossed

[@HB9BLA]

Interesting. Do you have a license?

[@tomekdziekonski7478]

@@HB9BLA SRC RYA- I was planning to use device on the boat (not in Switzerland). Yet BAKOM is testing the device, not license (I hope...). I'll report back with the result.

[@HB9BLA]

@@tomekdziekonski7478 So we will see what they say. These devices can be used on many frequencies outside the legal range and its power is also too high for non-licensed applications. Send me a Twitter or messenger message if you have the results.

[@doejohn8674]

Any news about your Retevis from BAKOM?

[@tomekdziekonski7478]

@@doejohn8674 Unfortunately it has not passed some tests and is considered to be non-compliant.

[@PE3FS]

The Baofeng handheld is not allowed in Germany and as I learned now in Switserland but still no peoblem in NL. You found already that the spike you couldn't explain is coming from your SA. I just bought a Tiny SA for about 70 euro an amazing piece of work. You have to try it. BTW nice video

[@HB9BLA]

You are right, the TinySA is a very interesting device!

[@mickgibson370]

When you're directly connected to the radio, there could back stream radio connection by capacitance, ignoring the filterance. I have Baofeng BF-F8HPP.

[@HB9BLA]

Maybe. But the cables and the attenuators are quite good shields.

[@EA1EF]

Thanks for your shared work

[@HB9BLA]

My pleasure!

[@andye2005]

I think you may be overdriving the SA. Also I would, never connect a Tx directly to the SA (I have the lower bandwidth version on the siglent, so I don't see that spike) I use an RF sniffer that has a 20db attenuation between the main RF path and the sniffer output, then I add additional attenuation if needed to bring the signal down to about 0dbm In this test you are not really interested in absolute power, but just the difference between the main signal and any harmonics. If you don't have an actual sniffer ( I picked up mine on ebay for about 20 GBP) feed the output of the rig into a dummy load. There is usually enough leakage for a simple e field probe on the SA to pick up enough signal to work with. Andy

[@HB9BLA]

You are right. In the meantime, I added more attenuation, and the problem became smaller. I like more to work with attenuators than with a sniffer because I can check them out on all frequencies and usually, they are +/-1dB. And I checked the signal with my Spectran V6 and did not see anything.

[@leiferickson3183]

So I am not sure if my experiance has any meaning for your measurement problem, but I was trying to do some audio THD measurements with some pretty expensive scopes at work and discovered that pretty much all oscilloscopes have pretty high THD. So the problem might be that you are measureing the distortion of your signal analyzer. This is why you use a notch filter on the fundamental in order to measure THD.@@HB9BLA

[@FesZElectronics]

Very interesting problem! I wonder how difficult it would be to make an external low loss filter to fix the harmonics issues. I guess if you can bring the harmonics under the limit, it becomes "legal" again?

[@HB9BLA]

Unfortunately, we have to distinguish between „commercially available“ products and DIY. DIY is treated as an exception from the laws and is only allowed for licensed HAMs. The max. Number is 5 per design if I remember right. Here you must not harm others. If a supplier decides to sell a product it has to fulfill the law. Otherwise it is not aloud to be sold or imported. Technically, you are right. However the cutoff frequency is not easily to determine for a dual band handheld. P.S. nice to see you on this channel ;-)

[@FesZElectronics]

@@HB9BLA I kind of enjoy you content here more :D I was thinking about this topic a bit, and you would need separate filters for the 2m and 70cm bands - no dual use - the 2m has a harmonic right in the 70cm band so that won't work. What do you mean by "max nr. 5 per design"? Also I fully agree a commercial product should be legal and compliant to begin with, however since this product is quite popular for beginner ham's, fixing it, by adding an output filter, could be a nice fun project.

[@HB9BLA]

@@FesZElectronics Somewhere I read that the max. number is 5 (maybe to distinguish between "commercial products). But unfortunately, I did no more find this text. It definitively would be an interesting project. However, it most probably would not be used because it seems nobody really cares...

[@FesZElectronics]

@@HB9BLA I was reading about reviews and modifications for this handheld, and one topic that was mentioned was that a "better" antenna helps with emission but makes reception worse - I guess it picks up more noise and strong local transmitters (like FM); I'm thinking that the above filter, should help with reducing the out of band incoming signals and make the device work better. So it should not just help with harmonic emissions, it might improve reception - this is something users should definitely care about :D what do you think?

[@HB9BLA]

@@FesZElectronics Definitively! The usages I saw were when they used these devices for short distance at events and casual talking.

[@p1366]

Interesting video thanks. Passive intermodulation spur at 3GHz maybe? Congratulations on the new channel I really like the technical side of Ham Radio. Perhaps you can take a look at the interesting project from Russia called Hfpager.. Possibly some scope to link our IOT sensors via HF radio/NVIS maybe? Best wishes from Cape Town! 73.

[@HB9BLA]

Interesting project! Maybe it would work with the new QDX of QRP-labs. But for a sensor, we would need an inexpensive and small transmitter like the "Walkie-talkies on a module" for VHF and UHF. I cannot imagine to use my IC-7300 just for one sensor ;-)

[@playitlouder451]

Don't you have an Adalm Pluto? They operate up to 3.8 GHz. If the 3 GHz signal is real the Pluto should see it.

[@HB9BLA]

I tried it with my Spectran V6 and did not see a signal. But it is not easy with these broadband SDRs. They also "see" the fundamental and easily can be overhelmed...

[@playitlouder451]

@@HB9BLA Yes, it's going to be hard. With the Pluto's 12 bit ADC the dynamic range is 70 dB so you have to get it just right.

[@mcconkeyb]

Those odd signals many harmonics away from the fundamental are always problematic. They can occur due to non-linearity in any part of the measurement system. Thus you have to calibrate everything in the signal path, like the cables, connectors, attenuators, etc. When I worked at a lab that did testing professionally, we spent 3-10 times longer calibrating all the parts of the system, than we spent actually measuring the system. Good Luck! :-)

[@HB9BLA]

Thank you for your wish. I think, I will need it. So far I am pretty sure that the devices are clean and the peak comes from my SA.

[@tommihommi1]

having a good signal generator that can do a lot of power helps.

[@BerndFelsche]

Excuse me for not being a ham or even EE. Try a low-pass filter with roll-off at say 1GHz. What doesn't then attenuate is a measurement artefact.

[@HB9BLA]

You are right. A high-pass would attenuate the base signal. Maybe I have to search for one at around 500M. Then the instrument would not have to handle this high difference....

[@HA7DN]

Here in HA land we are often recommended to get an UV-5R as our first handheld (or even first radio). Still illegal, but hardly ever enforced. (no, I did not get one. I'm waiting for my Yaesu, damn the chip shortage)

[@HB9BLA]

It is the same everywhere. This was the reason for that video. If you can get a clean RT85 for the same price, why buy a Baofeng?

[@godfree2canada]

But through a tuned antenna the spurious signal is over 6 SWR well below 60db

[@godfree2canada]

Regulations are ERP

[@mahudson3547]

Looking at yours spectrum analyser, the dynamic range appears to be close to 60dB. You could be driving the first mixer quite hard. If you repeat the measurement with say an additional 10dB of input attenuation, does the artefact drop by the same amount? Ah. I didn’t read previous comment… You also don’t need to drive straight into the analyser. A loose coupling to a dummy load (or the antenna) will give you the fundamental and any radiated harmonics.

[@HB9BLA]

Its dynamic range can be higher, but not at this RBW. But I agree that it has to do with some internal mixer (s). I tried to add 10dB attenuation and it was better, but still not gone. I compared now all handhelds on my Spectran V6 with loose coupling and there was nothing on this 3GHz spot from the RT85 and the IC-705. The Baofengs had spikes on many harmonics ;-) I consider this as proof that the spike comes from the SA itself.

[@acopernic]

Strange harmonic indeed. Have you check the length of your cable and each attenuator.

[@HB9BLA]

I will try it with another cable length (or no cable at all).

[@chuxxsss]

Morning mate, another ham show. Andreas were the tap for the power watt meter in the diagram?

[@HB9BLA]

The spectrum analyzer measures the power in dBm.

[@mahudson3547]

We’ve had this conversation before. 145 x 3 = 435. It’s the third harmonic NOT the second!

[@HB9BLA]

You are right. I am still not good at counting :-(

[@godfree2canada]

HT have an internal clock eg 26Mhz this can interfere with other on chip computers in other devices

[@HB9BLA]

Maybe. But it seems the signal is coming from the Spectrum Analyzer.

[@daveys]

This was bugging me, so I did a bit of searching. Nyquist foldback aliasing was the closest description I could find of what you are experiencing.

[@HB9BLA]

And what does it mean? And how could it be avoided? I am not sure if the sweeping SA does sampling. AFAIK it only measures one frequency at a time.

[@daveys]

@@HB9BLA - As far as I could tell, it’s caused by frequencies above the Nyquist limit creating aliases. The frequency of the 3GHz artefact moving lower as you increased the VFO frequency made me recall something similar that I’d read before. I’m keen to know what’s happening as I have an IC-705 too.

[@daveys]

@@HB9BLA - I have definitely seen this issue described before in something I have read. I’ll have a further look today - I have four books on testing and the like that it may feature in.

[@HB9BLA]

I now checked if I find any info about the sampling rate of the SA. But I did not. If I recall right, it multiplies the signals to above 3GHz and mixed them down. Maybe something goes wrong there...

[@daveys]

@@HB9BLA - I am not sure. Apologies that I was not able to help!

[@nicksouthon1557]

Another thought provoking video - Thank you Andreas. Regarding the attenuators - Have they been calibrated? As the objective is to measure the Db comparison between the primary frequency and the harmonics, this may be less of an issue for 1st harmonic, but have the attenuators been checked that they have the same attenuation across the range being measured ? G1GRW

[@HB9BLA]

You are welcome! My lab is not very high quality. Usually i try to stay in +/1 dB across the span of my SA. So the reason must be somewhere else :-(

[@KillerSpud]

I wonder if it is the length of the cable. 3ghz is 10 cm, and your cable looks like it could be a multiple of that? Try a few different cables if different lengths and see if that peak changes.

[@HB9BLA]

I now tried without cable (just an adapter) and got the same result :-(

[@catalinalb1722]

Hello Andreas, THe IC-705 can be hacked for CB bands, Andy Kirby did this but his video was banned (or he removed it) after ANCOM in UK complained. Regarding LoRa Gateways for thingsnetwork, is the SX1302 a good fit? Thank you, DE1CTL (Swl)

[@HB9BLA]

40 years ago my FT-277 was also able to do 11m. Of course we never tried ;-) The SX1302 is one of the standard gateway chips. I think they have now a new one. But this one is still used everywhere. It is not for sensor nodes.

[@w8lvradio]

GT-5R fixes the harmonics problem of UV-5R. 73 DE W8LV BILL (W8LV/VE3 prepandemic.)

[@HB9BLA]

I saw this, too. But I think this model is only sold in the American market. At least, on AliExpress I do not get any hits.

[@Luke-san]

And all of them Boafengs are still being sold on Amazon Germany and all of the other amazon stores. It bothers me a bit since a lot of non licensed people are interested in them to unknowingly 'play' with it as a sort of long range PMR.

[@HB9BLA]

You are right. That is a different problem (and maybe the bigger one).

[@BruceSchaller]

Fisher price smart tablet might be good with a LORA module installed.

[@HB9BLA]

Why do you think?

[@Chris.E]

SA artefact? Have you tried a larger attenuator and/or different cables?

[@HB9BLA]

I did now some additional tests. Different cables did not help, but more attenuation reduced the spur. But not completely.

[@PhG1961]

You should visit the PMRExpo (Köln Messe), the Baofengs are everywhere... and they claim excellent specs... ;-) We all know better....

[@HB9BLA]

Maybe they have different models for the PMR band...

[@PhG1961]

@@HB9BLA They have about anything you can imagine... that's how they are ;-)

[@rikkardo9359]

Was passiert eigentlich, wenn man wirklich mal ohne Freigabe sendet? Steht dann 10 Minuten später die Bundesnetzargentur vor der Tür? Ist es ok einen Impuls von wenigen Sekunden auszusenden?

[@HB9BLA]

Das weiss ich nicht, da ich das nicht mache. Aber vermutlich ist es wie mit dem zu schnell fahren...

[@rikkardo9359]

@@HB9BLA I see, danke für die Antwort. Deine Videos sind super, guck ich echt gerne

[@mt8385]

What about the Quansheng UV R50 or other chinese TRXs?

[@HB9BLA]

I only tested the ones I have in my shack :-(

[@houndogjohnson4013]

Baofeng now sells a legal fcc approved version of uv-5r.

[@sempertard]

Do you have a model # please?

[@houndogjohnson4013]

@@sempertard Gt-5r $24.99 from radioddity, hope this helps you out.

[@HB9BLA]

It is called GT-5R but it seems it is a US device made for Radioddity (kzbin.info/www/bejne/Z3vcfmulg9mil6c )

[@sempertard]

@@houndogjohnson4013 thank you!

[@sempertard]

@@houndogjohnson4013 So how the hell do they do it? $25.... I don't get it.

[@godfree2canada]

Baofung trashing is a cult

[@SteveWrightNZ]

Baofengs aren't illegal. Hams are allowed to transmit in their own bands with any piece of homemade junk they like, and as long as the harmonics are in-band then no one cares. Ham radio is about experimenting and making things and not caring too much about the commercial rules - not what the self-appointed band police will tell you, but their hobby is policing, not "radio".

[@HB9BLA]

I agree, and I for sure am not against experimentation. But I think we have to comply with the law. This is also the reason that we are asked to pass a test and get a license. Otherwise this would not make sense for me.

[@SteveWrightNZ]

Baofengs are only illegal for non-hams. Also on the ham bands no one really cares about the rules, and certainly no one cares about the band police. Do what you want on ham radio. It's only important to not interfere with someone else doing what they like.

[@daveys]

Very good point. That’s why we have harmonically related bands available to us. Most of the licence relates to staying in band and how to deal with annoying non-hams as far as I recall.

[@BlackVelvet446]

BAOFENG ARE BEST RADIOS !!

[@matheokoning4456]

Would really like to see how you can make your own 433mhz rf sender. And by that I mean imitate such a cheap module so that I can process it in my own pcb. I've tried several schemes online but can't seem to get it to work. I can't seem to find any info on how to troubleshoot this.

[@HB9BLA]

Are you a licensed Amateur Radio Operator?

[@matheokoning4456]

@@HB9BLA No, but I also just mean those simple transmitters that you can also find in your doorbell, for example. Or do you even need a degree for that?

[@HB9BLA]

No, not a degree but a proper amateur radio license :-(

[@matheokoning4456]

@@HB9BLA oh really yes? thought this was just something harmless. Just wanted to make it as a lamp switch in my own project and own pcb to develop myself a bit.

[@sharg0]

@@matheokoning4456 AFAIK all/most countries requires a license for manufacturing of transmitters. This is to make sure the designer knows how to keep the device within legal limits - the harmonics showed in this video is one example on how easy faults can appear. (Disclaimer I'm not a HAM but interested and did my military service in "signals")

[@MerLin613100]

73. I was a ham during college.

[@HB9BLA]

Maybe you will restart like me (after nearly 40 years ;-)

[@MerLin613100]

@@HB9BLA Thanks for responding. I'd like to restart but have not really found relevancy since cellphones have taken over the wireless communications scene. Although, it's a nice hobby. I wish you more power and 73s!

[@HB9BLA]

I do not do a lot of QSOs. I mostly experiment...

[@moenibus]

Dear ignorant or biased youtuber: they aren't "illegal", they don't comply with FCC RULES and REGULATIONS. ok? not laws, but rules and regulations

[@HB9BLA]

You are right if you talk about the Baofengs.

[@moenibus]

@@HB9BLA i talk about any radio. regulations are not laws.