#1185

Episode 1185
WARNING: +12dbm output power square wave
Sent into the channel by Junshuntong on Amazon: tinyurl.com/2w...
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[@germanjohn5626]

In typical fashion, he made a video without exploring the functions of the unit. Had he done so, he would have found that pressing the IF button longer he could cycle through 3 different setting, 455khz IF, 10.7Mhz IF and no IF, straight generator mode. The nice thing with this unit is that the amplitude is pretty stable over the wide range not like other junk on the market and thus a step attenuator can be used to make a pretty good signal generator for sensitivity measurements. We bought 10 of them for a school project from different sources, every single one of them was maximal +- 1-5Hz off at 10Mhz. Pretty darn good for a device like this.

[@Guns_N_Gears]

Can you calibrate it at all, or is that locked out?

[@Hammerjockeyrepair]

the reason the front says transceiver is because it goes with a few other components to make a complete mini ham station, They sell the transmitter and receivers that match this cute lil box

[@PA1JPR]

This project is just a copy of the guy that has designed it, and put it on youtube one year ago, see below. Same display layout etc. 10kHz to 225MHz VFO / RF Generator with Si5351 and Arduino Nano, with Intermediate Frequency (IF) offset (+ or -), RX/TX Selector for QRP Transceivers, Band Presets and Bargraph S-Meter. See the schematics for wiring and README.txt for details. By J. CesarSound - ver 2.0 - Feb/2021.

[@andymouse]

Nice little build and now you tidied it up even better...cheers.

[@M0UAW_IO83]

Neat little product as the basis of a transceiver but it's an Arduino, Si5351 breakout, CH340 USB-Serial, TP4056 LiIon charger, SSD1306 OLED, that's what, $15-$20 if you buy them all as modules? That enclosure better be *real* nice for $60

[@justinelliott3529]

I think it’s because not everyone is an engineer but they want the experience of building something. The VFO is the most complex part of a transceiver and with this it’s plug and play. You’re not spending hours screwing with incompatible sketches etc

[@Plons0Nard]

A small correction: it is not Arduino based. Both (many of) Arduino's and this device are AVR-based. Atmel was taken over by Microchip several years ago.

[@johnwest7993]

So it's designed to be used as the front-panel of a wide-coverage transceiver with a 455 kHz IF, but for some reason it didn't sell, so they put the front-panels in boxes and are trying to sell them as VFO's. But you can't program it to match your IF and you have to make sure that the odd order harmonics are suppressed, at least on xmit. Oh, and they want close to a hundred bucks for them. Good luck with that.

[@stevec5000]

How does it work with a transceiver with a 455 kHz IF? Is it what you use to set the rec. frequency?

[@cbfadiohamfan]

✅😎kool vids …👍 Hello would this be good to use on the ubitx v3 to controll the frequencies ?? 🎉🎉

[@MrRW1980]

well for data modes you need a signal carrier and then in a second unit you can do the frequency shifting stuff...russia studiec every time 5-6 times the propagation of experimental carriers bevor the applied the MFSK XX stuff ....you can create your personal data mode on HF

[@jercos]

I expect the "S-meter input" is meant to be *from* an S-meter, a linear analog voltage representing the signal strength for the display. The absent C7 would deliver another frequency from the synthesizer for a "BFO output" instead.

[@augurkur]

It's only missing a single IC chip. Connect the output line to a Tayloe circuit and you have IQ for your sound card SDR apps.

[@byronwatkins2565]

For those with quadrature encoders, swap either the two phase A wires or the two phase B wires -- don't swap A wires for B wires.

[@IMSAIGuy]

there is only three wires

[@RideGasGas]

Output port is mis-labeled. Frequencies in kelvin hertz (KHz) to mega hertz (MHz). Should be kilo hertz (kHz) to mega hertz (MHz).

[@willthecat3861]

It's ... I hate to say it... Chinese junk... part of some manufacturing, someone in China picked up, and decided to put in a case and sell.

[@W1RMD]

you would like Kaplan America's channel!

[@francisdevasia3150]

How to change IF frequency to another one ?

[@egonotto4172]

220 mHz = 0.22Hz !!!!!!!!!!!!!

[@Guns_N_Gears]

For thr viewers, the IF is selectable by long pressing the IF button, and the display iaroind .96. Its useless!!

[@Cesarsound1]

My original project working in a superhet receiver: kzbin.info/www/bejne/bWPHiXqMq7qUe5o

[@IMSAIGuy]

excellent, looks like fun

[@jspencerg]

PSA suggestion: Always show insertion of attenuator when testing unknown sources(though this battery powered thingy unlikely high power).

[@IMSAIGuy]

I should. I am very sloppy in my lab because the HP spectrum analyzer is protected to +30dBm.

[@jspencerg]

@@IMSAIGuy I thought of it only because I'd just watched your video about protecting the tinysa. I'm expert in laziness and procrastination. I'd say you were just being complacent in this case. :-)

[@willthecat3861]

Thanks for the interesting video. This thing, with shipping, is the better part of 100 USD, on Prime. For 20 bucks, OK; but, for 20 or 30 dollars more, you can get a complete Chinese wide band SDR receiver. Maybe stuff like this wouldn't see the light of day, beyond China, if it wasn't reviewed, and implicitly recommended on KZbin.

[@fromgermany271]

I know some guys are not really used to metric, so I’m already happy about not being confronted with an imperial frequency measurement. But there is big difference between mHz and MHz, as m and M are case sensitive in metric of about 10^9. milli and Mega is not exactly the same 😂

[@keithdensmore7766]

I have one of these. Is is possible to program a different IF shift? (I need 2.920 MHZ).

[@andye2005]

The link to the sales site provides a lot of information of what this little unit fan do. Tuning steps of 1Hz, adjustable IF + or - (so no real need to bodge the switch) The band change is 20 channel programmable The only problem is finding the instructions. It's a useful little box, but really rather too expensive when a simple 5351 and little ardunio / rPi pico wouod do the same job. Looks like a very similar project is on Project Hub by CesarSound published January 2, 2021 The code and circuit is all there. Andy

[@antoniskarnar8433]

hello my friend!! i want to ask how much mV have the generator?

[@IMSAIGuy]

+12dBm is 0.9Vrms into 50 ohms

[@antoniskarnar8433]

@@IMSAIGuy thank you very much!! But I ask you because in Amazon say for this item (Power 0.1 mw) In dbm there is no logic!! Sorry for my bad English!! 😅

[@tonyfremont]

Seems like there would be software options for the direction and IF settings. Surely it can tune in finer steps than 5kc too.

[@willthecat3861]

There could be. But if one wanted to mod the firmware (as opposed to accessing options from the software interface provided) then that could be a rabbit-hole project. I'm guessing that the manufacturers of this thing 'borrowed' the hardware and software design, from somewhere (maybe even from the chip set manufacturer) so there may be a lot of work to do to customize and work out bugs.

[@NavinF]

Here’s a silly question from someone with very little experience with RF stuff: Why do expensive HF radios exist? Given a stable clock, can’t any 300mhz microcontroller output a square wave at ~10mhz which can be amplified with a couple of cheap MOSFETs and filtered with a 2 pole low-pass filter to remove the harmonics and get a band limited signal you can broadcast?

[@joelandjen]

You just described a simple transmitter, which is not the most difficult part of a transceiver. The receiver makes or breaks the performance for a ham operator, and the receiver is much more complicated. Some manufacturers do better jobs than others at that, and that is why expensive HF radios exist. But there are excellent receivers in some less expensive radios, depending on what your goals are.

[@paulgrodkowski3412]

this gives me a headache!!!

[@bumohamedubualooy7111]

can u make a video about ad 9851 dds i cant get a steady sine wave even in under 5 Mhz from it. tnx in advance

[@IMSAIGuy]

I did this video: kzbin.info/www/bejne/b5CkXnubirCSa8k actually a two part

[@aduedc]

Good that you tested it. Real Bad harmonics, as a sine wave generator ! If it is square wave let's see it on oscilloscope and look at eye diagram and measure rise time, fall time, and probably jitter.

[@M0UAW_IO83]

It's got an Si5351, it's definitely square wave.

[@aduedc]

@@M0UAW_IO83 I think it is to be used for Ref. clock of PLL.

[@chrisharper2658]

Isn't the thing kind of worthless given all the harmonics? I was also wondering about jitter.

[@IMSAIGuy]

almost all the DDS chips are square waves, they are not useless, just require care and filtering to use.

[@chrisharper2658]

@@IMSAIGuy Okay, Now that I think about it, I've got a Ham-It-Up up-converter and I think it uses a simple low-pass filter but that is a fixed frequency so that would be pretty easy.

[@josequinton6940]

spotted this on amazonk cute lil box searching for ham radio stuff so off to you tube wondering what is it, this video left me more confused but thanks $75 for a cute lil box {VFO} that can't even sing "me chinese, me play joke, me put pee in your coke" is beyond me.

[@rfburns5601]

You should connect that to the IC-245! Ha!

[@rfburns5601]

No Kiddin' . I might get one for mine.

[@paulcohen1555]

Is it Okay to call a square wave generator "VFO" for a receiver?

[@joelandjen]

Yes, it is. Doubly balanced diode mixers perform better with square wave LO input. It just requires filtering at the output, that is all.

[@pleasureincontempt3645]

These sort of metrics I don’t understand. If everything were to break down, so to speak; I would like to have the utility of talking with people over distance. You seem like the person that would know that.

[@nagasainathkoduru9995]

Put a toggle switch for PTT