Testing Quansheng UV-K5 (8) - Harmonics - TinySA

[@SheffieldVince-2E0NZS]

Hi Ben. You mention a "1st harmonic". I may be incorrect but, I think that would be called the "2nd harmonic". You have your main transmission frequency,, then the next harmonic is called the second harmonic, then third, then forth etc. Strange! But true. Good demonstration showing how clean an actual radio designed for 27mhz is compared to the Quansheng.

[@m7frs272]

That's interesting, thanks for the info and thanks for watching 👍

[@fotografm]

The "first harmonic" is the fundamental frequency.

[@m7frs272]

@@fotografm Thanks 👍

[@johnwest7993]

It was defined by physicists to suit the applied mathematics, as in anything multiplied by 1 is the original. So the 1st harmonic is the fundamental freq multiplied by 1. It keeps all of the applicable math simple.

[@David-km8in]

Yes a great radio for experimenting. And great for use on VHF/UHF. I've brought two, one for a friend and one more me. I've changed the firmware to improve the am receive and make the display look better. Been testing it on our local repeater. Good audio report to. All your findings match up with tests done from our radio club members who have them. Overall very pleased with my purchase. All the best David M0DUU

[@ddouglas3687]

Very nice sir! I'm glad someone out there has put the uvk5(8)-6 through its paces! I like the uvk6 for its ability to be opened up to at least be a broad spectrum receiver but wondered about its spurious emissions which I knew would be chaotic. I plan to get one at some point because it just looks like such cheap fun! I'd built many quad beam antennas back in the cb days so cannot wait to start having fun with the uvk6. Working on my tech as we speak! Tnx and when I'm up and running, I will def be shooting for contacts in the UK with it! Radios are so much fun! I've also dug out a couple of old hand held cb's that have been kicking around since the '90's and rebuilding a quad beam soooooon! Tnx again Ben sir from the stix in Central Virginia, USA!

[@m7frs272]

Glad you enjoyed it and thanks for watching 👍

[@David-km8in]

Hi, the harmonics are very low on UHF/VHF amateur bands. But terrible out of band. I heard tx on 11 meter CB band put out 200 milliwatts on the band and rest of the power on goes out on the aircraft band. Best wishes David

[@davidbrowne1588]

Hi Ben The designer of these tiny sa , say's to use an input lower then -30dbm for a better display,as nothing will be over loading, I know it will not make much difference with the results from these radios, Great videos, keep them coming, Good luck Dave 2E0DMB

[@paultomlinson528]

Nice video mate

[@gbamck]

I'm enjoying these videos, Ben. I have one request, please could you review your intro/outro morse using in-ear buds. It is painfully loud. Any chance you could soften the volume for us old duffers? 🙏🏻

[@m7frs272]

Thanks for the feedback, will do 👍

[@fotografm]

Excellent video !

[@m7frs272]

Thanks, glad you enjoyed it 👍

[@heinerrambold8889]

In some countries the regulations demand an attenuation of at least 60dB on VHF und UHF. For 6m and 4m one could make lowpass filters and put them between the radio and the antenna. Guess for CB the case is hopeless. Thanks a lot Ben!

[@johnwest7993]

Surprise, surprise! The output filters were designed for 2 meters and 70 cm, not other bands. Who woulda thunk?

[@m7frs272]

Exactly 😉 👍

[@technishn]

The transmitters definitely look like comb generators to me... Multiband.. All at the same time..

[@acestudioscouk-Ace-G0ACE]

You make the point of dangerous harmonics well. The CB harmonics getting into the air band is particularly worrying and has long been the case when "rig doctors" have overdriven output ratings.

[@StianEklund]

I believe you can set the external gain (under level, in settings) to specify any external attenuation you have applied. Set the internal attenuator to 30dB that'll help reduce the phase noise and should give a better reading.

[@m7frs272]

Thanks, I've since had a play with the settings and found that 👍 Thanks for watching and commenting 👍

[@figpanmusic4790]

Hello, thanks for the experimentation, have you ever tried to measure the spectrum in the other part of the extended TX between 800-1300 Mhz? I whish there were no undesirable harmonics🤞

[@RosssRoyce]

It needs a filter of some sorts!

[@ThePrawlin]

It isn’t just about adding a band pass filter. The radio final op stages are tuned to either 2m or 70cm. Forcing it to transmit on any other bands means the op stage tuning is miles out of range. It could even damage the op amplifier devices (as well as splattering all over the spectrum badly, and very illegally).

[@ExploringWithJason]

Really curious, does it transmit on 290mhz? And if yes..how many W? 😸

[@chipfornaris]

70 CM’s???

[@uzaiyaro]

I just ordered one of these, with the intention of using it on 477 MHz CB. I didn’t realise it only went up to 470 MHz. Can I still use it for CB radio, or should I refrain from doing this? I’m quite new to radio so some guidance would be greatly appreciated. Thanks!

[@m7frs272]

That's interesting 🤔 I've not considered it's use on the 477Mhz CB band as we don't have that allocation here in the UK. I guess that would be a test for the TinySA.

[@MauricevdfHermsen]

TKS !!! 73 de PD4TZ

[@darkstate5324]

I see theres mods for this radio, what about anyone modding the filters?

[@IW2BSF-Rodolfo]

@Ben M7FRS the name and link to buy this dummy load with double sma ? tnx 73

[@m7frs272]

www.ebay.co.uk/itm/386390045874?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=Y1JuX-SjTIK&sssrc=4429486&ssuid=JIoVKiWrQ3K&var=&widget_ver=artemis&media=COPY

[@JimmyCall]

Why aren't you tsting with narrow-minus / 6kHz filtering?

[@m7frs272]

I'm still learning how to use the TinySA 😉 Thanks for watching 👍

[@ThePrawlin]

You are overloading the TInySA input! This will create many false harmonics/spurs created inside the TInySA! You need a minimum of 60dB external passive attenuator for this test. But better with say 70dB in line. I’m afraid this test is partially invalid due to the inadequate input attenuation. Sorry. Having said that, you are 100% correct that the quansheng must never be used to transmit outside of the 2m/ 70cm bands else huge OOB harmonics will occur everywhere.

[@m7frs272]

Hi thanks for your comment. I'll certainly look into this as most people, like myself are using 40db attenuation for this test and Erik, the designer of the TinySA recommends a minimum of 30db.

[@ThePrawlin]

@@m7frs272 if Erik does say that, I suspect he is saying that is the absolute minimum external attenuation so as to not cause possible input circuits damage. He also says somewhere that to minimise internally generated false spurs, the optimal input level needs to be kept quite low. I can’t remember the details OTOH now. Cheers.