Frequency Counter And Crystal Tester / Meter - Assembly And Testing

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I purchased this frequency meter kit not to measure the frequency of the crystals, instead I wanted to measure the frequency from the receivers and transmitters I am building.
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73, YO6DXE
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DX EXPLORER:
A channel with amateur radio related videos on: schematics, kit building, homebrewing and more.
I am passionate about amateur radio since childhood. I got back into the hobby in 2016, while living aboard my sailboat. I received my license in 2022. I like QRP mostly, experimenting with all modes. But I am old school, so I prefer SSB or CW.
#amateurradio #hamradio #electronics

[@sebastian19745]

I know it is an old video, but I am commenting just for the algorithm. And, maybe someone would find the info useful. The crystal oscillator is powered from the input voltage but the PIC MCU is powered with 5V. The oscillator may work well for some crystals at 9V or at 12V, depending the crystal and the transistor. The configuration of the oscillator is quite bad, I had it working at 9V up to 4.433MHz and at 12V it worked well with 27MHz crystals and some ceramic resonators. The low frequency crystals most of the time do not work (1MHz, 32kHz, 500kHz or 450kHz ceramic etc). If the crystal is good and oscillate, the counter will show the frequency, if not, may try to increase the input voltage from 9V to 12V. I would not exceed 12V. The PIC input is digital so to work well it need the input signal to be in the TTL standards (low2.7V). May be useful to use a preamp and a Schmidt trigger (7414 or similar) to drive the input. For the tester to work, the output of the oscillator must be in the TTL level specs and some crystals and ceramic resonators just do not oscillate well enough for the output to be good enough. After assembly, the circuit must power up and work just fine. The only adjustement is to set the 20.00000MHz refference crystal oscillator with the regulable capacitor. I find that sometimes the 20.000MHz crystal is so bad that it can not be trimmed to oscilate on 20.000MHz, so I recommend to change it with a quality component. I got a good deal for a pack of 5 and I used them in a RF generator, a TTL clock generator, a GDM, a portable frequncy meter and I made my custom crystal tester.

[@dxexplorer]

Thank you so much for the commend and also for all the info. Ohh I ended up modifying mine following the instructions from a video I will link down bellow. I decided to transform the crystal oscillator into a preamp as I didn't use the oscillator anyway. For now it works fine, but I haven't tested it on all frequencies yet. Thank you one more time. 73, YO6DXE. kzbin.info/www/bejne/ZnPboYCja7h_pacsi=pnKMNnEENKBY0uap

[@sebastian19745]

@@dxexplorer I know that video and it inspired me to modify them. However, to use the module as frequency meter without loading the circuit (or in GDM), I used a old circuit that i found in an old Tehnium magazine (wide band input buffer with FET). The circuit worked fine up to 80MHz, the max that I used it, powered with a 7812 and shielded. As for the crystal/ceramic oscillator, I built myself 3 separate oscillators each for a frequency range (LF, MF, HF); I adapted various schematics from the same magazine.

[@dxexplorer]

@sebastian19745 Amazing idea with separate oscillators. About Tehnium... I still find a lot of great schematics there that I try to bring back to life... when I have the free time 😁. The magazine the open an entire new world to me.

[@tubeDude48]

It could possibly be the PIC Code needs some tweaking! Good luck in finding the guy who programed the PIC! Also, did you check the value of each component?

[@dxexplorer]

Ohhh no it was something else. I had to modify the oscillator circuit and turn it into an RF preamp... not it works like a charm.

[@tubeDude48]

@@dxexplorer - Glad to hear it !

[@dxexplorer]

@tubeDude48 Is just the signal was too low for the input of the counter. I rarely use it now as I have a smaller one now but is there just in case 😁

[@stewpot3971]

I would be interested in seeing a video about the license types and process in Romania. Good luck!

[@dxexplorer]

Not a bad idea at all. Then I guess that's what I'm going to post next.... ) 73 and thank you for the idea )

[@stewpot3971]

@@dxexplorer 👍👍

[@dxexplorer]

@@stewpot3971 Have an amazing weekend and thank you again.

[@pd1jdw630]

Good luck on the exam! 👍🏻👍🏻

[@dxexplorer]

Thank you so much my friend. 73

[@johnkris753]

One more note, the crystal test part off the kit is not usable on lower range crystals, it depends on stabilized voltage you are powering the kit. (Wau how much i wrote....) Keep up good work. Cheers

[@dxexplorer]

It seems from what I found online ( I haven't tested that yet ) that by replacing that 22pF capacitor that also has another 22pF capacitor in parallel as shown in the video with a 68pF... you can measure the crystals over 26MHz up to whatever the PIC can take ( about 60MHz ) with no problem. For crystals under 26MHz the capacitor must be 150pF. I guess that could be an easy fix with a switch. Now I go over on the other comment )))

[@johnkris753]

The preamp that got me to stable readout(to 6Mhz only😔) was "termination insensitive amplifier" by W7ZOI. I am hoping to be able to modify it for this kit. Check it out it is good preamp for all sorts of things 😉

[@dxexplorer]

Thank you John. I will search for it when I wake up. I'm nearly in wonderland here )) 73 my friend.

[@4youian]

Hi Chip, glad you got it working. I have a similar kit and the crystal oscillator seems fine with 12v battery. I suspect though that the capacitors in the feedback network are too small for lower value crystals. Maybe 100p would be better. Hope your license test goes well! Take care, Ian :)

[@dxexplorer]

Morning from Transylvania )) Yes Ian that's the issue. I found on many blogs that people usually replace it with 150pF capacitor for low frequencies... and 68pF for higher frequencies. I haven't tested to see if it works or not as I transformed the oscillator in preamp to get the counter working hahaha. I will build another one on a separate board. Thank you... fingers crossed the exam goes well. 73 and we catch up soon.

[@Sickindian5]

Hey pal I assembled my one yesterday and it doesn’t seem to power at all. I followed all the board signs and checked values with meter. Any clues how to diagnose the fault??

[@dxexplorer]

I did not had that issue. Maybe it would be good to check the voltage regulator to make sure it works ? Is a cheap kit so I guess it would also use cheap components that may not always work properly.

[@Sickindian5]

I was wondering if the chip works but ain’t sure if it’s programmed or something??

[@dxexplorer]

@Sickindian5 mine was all set and programed, I didn't had to do anything just to put the kit together and it worked. But I did heard others as well saying that they had issues with it.

[@Sickindian5]

I think there might be no instructions on the PIC16F628A chip. I will try to read the data tonight off it.

[@dxexplorer]

@Sickindian5 I have no clue how to do that. I don't even have what its needed to do that.

[@stevemiddleton948]

Can anyone help me please.. I just built this kit and it powers up but when I plug a crystal in it stays on 0, the solder joints are all good and the kit has been built properly, I do soldering for a living and make fire alarm systems but I don’t know why it’s not reading the crystal? I’m putting 9v into it for power as it says I can do that on the board but is that causing an issue at all?

[@dxexplorer]

Honestly I don't know as I modified the kit right away and transformed the crystal oscillator into an RF preamplifier. So I never tested crystals to see if it works.

[@arjunkumartb6585]

How can it used for measuring a signal from Signal generators ..

[@dxexplorer]

To be very honest... that I don't know. I don't have a signal generator so I can't really play with it to see. I assume that it depends on what signal is generated and on what frequency. More than this I have no clue. 73, YO6DXE. P.S. Maybe someone that knows the answer may reply on the comment hopefully.

[@outofround]

Yep. I had the same problem. Wouldn't read from the oscillator circuit from a SW receiver. Maybe it needs square waves rather than sine waves???

[@dxexplorer]

Not sure. Maybe the signal was low ... low as in output for the frequency meter. I noticed in some regen receivers if I added one or two more turns to the pickup coil, it would fix the issue. ( using the modified frequency meter not as it comes as a kit ).

[@2ftg]

These are great low cost frequency counters. They can also be used as displays for DSB transceivers. Sadly the original code no longer compiles in microchip mplabx.

[@dxexplorer]

I'm very bad on coding stuff to be honest... so for me I can't say that is a big loss ))) But I imagine the struggle. They are really cool indeed. And really cheap too and that I love the most )) 73

[@surgingcircuits6955]

With the programming button, you can do a reset that may help.

[@dxexplorer]

I ended up modifying the circuit and instead of crystal tester I changed it into a preamp. Works like a charm now 😁.

[@ramyramdani2425]

terima kasih teman ku . skema pre amp ini sangat membantuku terima kasih 👍👍👍

[@jerryuhte1284]

Sorry things didnt work like you wanted but i am sure you will figure it all out ! Good luck OM ! 73 K9UT Nice work !

[@dxexplorer]

Thank you Jerry... it's ok if it didn't work. At least I'm learning some new things out of this.. so at the end there is no loss )) 73 buddy.

[@hendrikmetz3905]

Hendrik must be a great mate ;)

[@dxexplorer]

This Hendik guy has a garden full of antennas ... more antennas than trees in my garden hahaha. Thanks so much my friend. After the exam I will show you the finished receiver )) 73 and we catch up tomorrow. I have a feeling you have in plan to do some stuff in your magic workshop ))

[@2222MalayalamElectronics]

Add a preamp and you will be good to go. Reading frequency from regenerative radio is a bit difficult in my experience even with oscilloscope. They work better in superregen mode

[@dxexplorer]

I noticed that if the receiver is oscillating too much.. the meter goes crazy. But since with the Sputnik I made the regen control really smooth... I can set it in such way that is more like a direct conversion receiver instead of regen ))) So the frequency meter is spot on. Is important I guess to have a good read is important to set the oscillation properly and then there are no issues. There will pe a preamp soon as I have some present from one of the subscribers. I'll make a video about it of course ))

[@johnkris753]

I thought that you will help me with the same problem (when i saw that little board that your friend send to you from your earlier video)but let i help you, to the degree that i came to.(I am still experimenting to find solution 😔) First watch video on KZbinrs channel "theHWcave" he did amazing job on explaining the input on PIC and the limitations on same kit. The problem is that you have to have max 5vpp on the input of PIC to be able to count, but 5vpp above 0v.( It is difficult to me to explain it on english it is not my native language...). Signal has to have offset from 0v but max amplitude 5vpp. I bought same kit as you, and wanted to use it as a frequency display for analog signal generator that i am working on. Other note, you have to power it with stabilized dc voltage from that little socket on the board(6v minimum , that also worked best for me..). Things are little complicated...preamp has to have three stages. The first buffer then amplifier and then again buffer. And of course AGC. Impedances have to be equalized or you will lose signal( I don't know what your bandwidth is in interest but i am having problem because i have to cover very wide bandwidth and have stable amplitude in whole range). Difficult, but doable 😉. Just like you, this is hobby for me, and if i have time in the future i will do more tests on my preamp which may help you. Also keep testing and experimenting ( the journey is important) with it and if you come to solution please share it with us.

[@dxexplorer]

I understand it all... no worries on the English as its not my first language either ))) I have seen the videos as well. I will do some more tests soon and I will come back with another video on this as soon as I find a solution. 73 my friend and have an amazing weekend. Yes... Sadly none of those preamps worked. The max signal I got from the three transistors one was about 1.5v.

[@ivand8393]

1. You have to clear the offset through the menu 2. The "input" goes directly to the PIC, therefore it must be below 5V !

[@dxexplorer]

Thank you Ivan. I found the original preamp schematic that was used in the "original" version of the meter and now it works perfectly 😁😁 no more headaches hehehe. 73 my friend.

[@DavidRichards-lh2hw]

I tested it and found that it read from 3.58MHz to 24MHz. I have a 27.14MHz which it failed to read, and a 4.433???? that read as 13.2????. I also have a 1MHz, a 2MHz, and a 2.4576MHz in the larger size case so they couldn't fit the socket. Your mod actually made it worse, so I reverted to the original vrsion and it works fine again.

[@dxexplorer]

I also modified it using other video as tutorial 😁. But in my case it works fine. I only tested frequencies from the receivers thought... as there is no longer a crystal tester circuit anymore in the frequency counter since it becomes an RF preamplifier. So technically with the modifications it shouldn't be able to measure crystals at all. Using the original design yes it has an oscillator circuit that will allow us to measure the frequency of the crystals. Those I do know that have some issues and if I remember well there was some capacitor value that had to be changed depending if we would prefer to measure low frequency crystals or those closer to 30MHz. So maybe that is why it won't measure the 27MHz crystal. I can't remember now what capacitor had to be changed as I no longer have the crystal tester circuit in mine. 73, YO6DXE.

[@jhilario]

Yo tambien lo monte y tampoco me funciono.

[@dxexplorer]

I just added a comment on top to explain what I did.

[@ishsnikaishsnika2066]

Hey,in this video I noticed that you build Sputnik 3.0 with classic cilindar coil :-)..The other day I did the same thing with my Sputnik considering I didnt satisfied with sensivity and after I changed coils, results are much much better!!! In thursday night I listened all europian stations very easy, even in one moment I heard american call sign(k4tew, I thik) very clearly :-)...about freqency counter and measuring freqency, my friend, beleave me, you should buy oscilloscope, your life after that will be much much easer! I paid my old analog 2xchanel 20MHz oscillscope with 2 new probes only 50euros in total, here in Serbia...with scope you can measure almost everything that you need during any RF building proces, including measuring of freqency, but you dont have to pay atention on input signal level and stuff like that, just put the probe at right place and thats it, without any preamp etc ...newer digital scopes show freqency automaticaly in decimal digits format, but the price is higher...check your mail, I sent you the link about your freq counter with very detail description of the constructor(dl4yhf), including the preamp stage, etc...these linsk below are from my favorite ham radio youtuber w2aew, and they speak about measuring freq, inductance etc, by the osciloscope... kzbin.info/www/bejne/hYKwn52Xgrh-pJo kzbin.info/www/bejne/bWXJq2yfrL-Sqa8 kzbin.info/www/bejne/fJeYqYJ7g653bdk

[@dxexplorer]

Thank you so much my friend. Ohh yes I'm still trying to buy an old osciloscope, but those are hard to find here. Especially when you don't know where to search for them ))) The frequency meter works perfectly now. I changed the circuit as the original design was, with that preamp described in the article. This morning I woke up to test it... and tanaaaaa... ot works amazing. 73 my friend.

[@ishsnikaishsnika2066]

@@dxexplorer :-)) Yes, I checked the mail and I saw that you mounted the freq counter on Sputnik and measuring is correct now, that is great news beacuse I also going to buy the same PIC counter for my Sputnik considering here in Serbia you can find it(in kit) for about 800din+shipping, so its less then 10euros :-)...second one based on esp32 that I tested is also good, but this PIC version is more compact and I like it much more, due to vintage 7-segment display :-)... about osciloscopes, here in Serbia we have nice internet marketplace (offers second hand and brand new things as well) where I bought mine scope, something like Serbian vesrion of ebay...I was waiting something about 6 months or maybe more where I finaly found what I looking for, so patience is necesary :-)...you can always try on ebay, I think that I saw few scopes like mine in similar price range(cca 50euros)...

[@dxexplorer]

I just remembered... if you don't have enough sensitivity in the receiver... you can put 10 turns instead of 8 on the antenna coil )) I didn't put that much so I don't have such a strong signal. About the frequency meter... ohh yes I'm so happy it works. Now I will also get some more kits to have them for receiver and transceivers. You know me.. I like old school stuff not the digital ones )) With the osciloscope... I will have the patience and find a good old one when I see it so I can get it )) Amazing tool to have indeed.

[@ishsnikaishsnika2066]

@@dxexplorer yes, thank you my friend, I already have 10 turns on my cilindar-shape coil but on the toroid one I have only 3 turns, so it can be the reason of the poor sensiitivity and weak signal, also I doubt that my toroid coil was too close to the pcb in my previous version, so I will try to adjust that...I am very glad that you achieved your goal with PIC counter, it is very nice feeling when circuit builders finaly succed after few days of strugling and experimenting, correct? :-)..ok, besides the scope, there is one more measuring device which is worth of buying also, it is nano-vna, price is ridiculous, cca 50euros for new one :-)...

[@dxexplorer]

I think NanoVNA will be first on my list... because is portable... then the osciloscope ))