HC-12 working supply

manuka

Senior Member
Stuart: Fair comment - horses for courses...

Jeremy Well said - largely my experiences & opinions too.

ZOR: As the HC-12's documentation insights are a tad wordy, I've rustled up a more concise AT summary for your reading pleasure. It's deliberately not PICAXE specific...

File uploading from here in NZ to the Forum has been VERY swampy recently -hope it arrives. Stan.
 

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ZOR

Senior Member
Many thanks Stan, arrived dry! Good to have it in concise form, a good reference. Regards
 

manuka

Senior Member
OK - glad the summary well received. Consider as draft since diverse extras & tweaks can be added. In particular delays associated with the FU1-4 "packets versus continuous" data sending modes may need clarifying. I'd also pondered adding PICAXE slanted code under the AT+Px extry (which is why a gap appears there). However the intention was to keep the reference micro generic, so maybe just pencil in your own ! Stan.
 

reginald

New Member
Fake HC-12?

I have been using a number of HC-12 but having problems with some not communicating. I thought they may be fake , bought five from ebay -Hong Kong. I have tested repeatedly and though they can transmit ok they have problem receiving . I have looked carefully at the boards and the main difference I have found is the crystals . The good boards are marked T300 6cxk the bad boards are marked 30.000 MHZ.So I dont know if the are fake but I will avoid boards marked as 30.000 MHZ. It could be the signal frequency is slightly out, Checked and rewritten the AT settings but no difference. I haven't tested the 30mhz boards with each other over a distance yet thought they do communicate locally. But it annoying to have two different types which are not totally compatible. Beware

1804101247172090928.jpg

1804101247302103845.jpg
 

reginald

New Member
I set up a T300 as a transmitter at FU4 1200baud max output counting from one upwards every second and three mixed type receivers all linked to pc with three usb serial interfaces. The 30mhz type repeatably dropped the odd number but the T300 were stable. Tried searching online for the T300 crystal datasheet but no joy. Perhaps best view is not to mix the types in projects. I have ordered five more HC-12 on ebay from spain for £20 which picture the T300 crystal and will wait to see what comes. At the moment I have got a network of four in use as master and three slaves over a distance of 4-5 hundred yards and they work well but the 30mhz types seem to lose incoming signals from the slaves but can pick up transmitted data from the master a few feet away.
 

manuka

Senior Member
An interesting one ! All my HC-12 are the original T300 types. The behaviour experienced no doubt relates to the crystal derived signals for the HC-12 channels being slightly different on the 2 variants. Hence HC-12 Ch. 1 should be exactly 433.4000 MHz & other channels exactly 400kHz spaced above (433.8000MHz,434.2000 MHz etc)

Best we don't rush to call these second sourced ones fakes! - they may well have superior accuracy... Stan
 

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PhilHornby

Senior Member
Interestingly, the picture of the HC-12 that appears in the "User Manual version 2.3B" shows a crystal marked 30.000. Perhaps those are the original ones?
 

manuka

Senior Member
It may be time to start a fresh thread on "HC-12 issues" ? Here's a FU-2 bug (?) comment from a "smell of an oily electron" T300 module Kiwi user-
I have found they are all working okay but one mode FU-02 (standby 80uAmp) looses the plot and just hangs on Rx. All other modes are too hungry for most of my work so my dual work around is to power them up only when needed anyway...
 

reginald

New Member
HC-12 genuine or not

Ok came across this on the hc01.shop site which I believe belongs to the manufacturer www.hc01.com . Though I don't understand Chinese they seem to show two HC-12 next to each other and one is ticked and the other as a red cross on it. If you zoom in to the picture the red cross one as a 30mhz crystal the other is the T100. Perhaps someone with language skill could decipher. I am guessing they are showing genuine and non-genuine HC-12. I am struggling to see the difference on the back of the HC-12 except for the thickness of the film as the plated through holes seem the same.

http://www.hc01.shop/productDetail?id=29
 

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manuka

Senior Member
My eldest daughter works in Asian trade, & although Mandarin fluent she is non technical...
Google's translate app. says
Product appearance similarity exceeds 95%, please carefully identify it. If you are not sure, please contact customer service to help identify! ! ! The difference is

one: the back white is heavy and genuine, the color is shallow and fake!

Difference two: the back of the white coverage is not complete, there is a 1 mm edge of the ink thin layer of English letters blurred genuine module ink is milky, moderate thickness, clear writing, cover full | side of 1 mm or so, no printing ink Oo Genuine Fake Back
This doesn't even mention the crystal issue !
Stan.
 
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PhilHornby

Senior Member
This does appear to confirm that there are HC-12's out there that are 'non-genuine'. It doesn't indicate what the detriment to the customer might be (if any).

I'm not sure that the photos are a definitive means of identifying one from the other either - I have some HC-12's that have HC01.SHOP's logo printed on them (rather than "HC-12") and some that have so much White 'resist' that you can't make out any of the holes.

:confused:
 

manuka

Senior Member
Phil: HC-01.SHOP logo - any pix ? All my HC-12s are "milky white " T300 crystal types - sourced via Satisfy Electronics. Perhaps it's time for a fresh forum topic on "HC-12 issues" ? Google finds this Forums postings so we'd be helping a wider audience. Stan.
 

Grogster

Senior Member
I have just come across what appears to be the fake ones, but was only pointed to this thread today. The fake ones are also off frequency by around 37kHz, and with a NB system, that IS important, so it would appear they are to be avoided. Apart from the frequency error, they appear to work just fine, but you need to be careful that the frequency error does not put you outside the band you are working in, as that would then make them illegal.

EDIT: Something to note is that a genuine one and a fake one used as a pair will give you HEAPS of problems, as they are not on the same frequency, even though you have set them up to be. With a genuine one and a clone the other day, I was losing about 75% or more of the transmissions cos of the frequency error - not good. So long as you have both genuine or both fake, they seem to talk OK, but mix them and you will have problems.

In my case, I was wanting to use 458.6MHz, which is a small slot in the UHF band for SRD here in NZ, but the fake modules run at 458.637MHz, which is outside of spec and therefore illegal. Genuine HC12 on Ch.64(458.600Mhz) is legal on that frequency.

They are 99% identical, but those photos show the two holes you need to look for as soon as you buy any HC12, and if they are there, you need to return them as fakes, and point them to the HC01 webpage as evidence. Bloody fakes...... I have used hundreds of genuine HC12's, and they work beautifully, but the cloner people always seem to stuff things up for everyone else. :mad:
 
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techElder

Well-known member
Grogster, I have HC-12s that have both of the different labels on the crystals, but have none of the differences that you identify in your posts. In other words, except for the crystal labels, they are physically identical.

I'm struggling with how to determine if the frequencies are different in a definitive way. I don't have time to devote to comparing channels or frequencies or pair compatibility, but I will do that.

Perhaps, the "FAKE" label is strong at the moment? It wouldn't be the first time that eBay facilitated the marketing of rejected production. :D

PS. Duplicated from the other thread.
 

reginald

New Member
I don't know if this applies to all the clones but on mine next to the SI chip between the corner of the chip and the RF socket there is a small capacitor. On my genuine ones it is coloured white on the clone 30.MHZ ones it is brown. Looking online I have seen most coloured like this except for the picture on the HC01 site where they both appear white. I have just had five come of ebay from Spain, advert picture shows T300 but 30MHZ arrived so have sent them back as not genuine. Going to struggle now to get the good ones as the pictures are no guarantee of what you might get.
 

techElder

Well-known member
It seems to me that you can't judge the book by its cover. :D

Grogster has concluded that the only true way to call one version "genuine" and the other "fake" is to measure the frequency.

Perhaps there isn't a "fake" HC-12 at all, but just an out of spec production run that has been dumped on the market.

The "fake" label should apply to one that doesn't work at all; a fraudulent item, to be more specific.
 

inglewoodpete

Senior Member
Don't discount the possibility that there may be several manufacturers of fakes. Not all fake versions necessarily have the frequency error that Grogster has discovered. According to the manufacturer of the genuine items, they use the silk screening to discriminate between genuine and fake. I don't envy their position - it is probably a minefield out there.:(
 

inglewoodpete

Senior Member
Tex, I'm not disputing that.

We don't have the means to determine what is real or not. The manufacturer says "silk screening" which does not, in itself, affect performance. We do know, from Grogster's investigation that there are some HC-12s out there (here?) that have a frequency discrepancy. Phil Hornby is reporting unexplained lock-ups.

All I know if that I have three HC-12s, bought in two separate purchases from different suppliers, that all interwork satisfactorily.
 
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techElder

Well-known member
That's right.

I now have tested some of my HC-12s with the "30.000MHZ" label, and they work just fine in my network. I can't tell the difference. I'm using channel 9600 + C074 + FU3 and sending 16 byte packets for as long as I can stand it. No problem shows up.

I'll have to dig out a scanner for the UHF band to try to determine what the frequency is, although I haven't had my scanner certified accurate in decades. I have used an SDR on my PC to look at the frequency and bandwidth of my "genuine" HC-12s, but that doesn't give much confidence in the actual frequency.

So, there ya go.

No doubt Grogster and Phil have observed problems, though I'm not sure it is systemic or involves any manufacturer other than the original one.
 

Grogster

Senior Member
Howdy. :)

Texas is correct. Perhaps 'Fake' is the wrong term for the reasons he/she stated. I will stop using it. I will use 'Clone' from now on.

I'd better keep hammering home that:

- Two or more genuine ones on the same network and settings: No problem.
- Two or more clone ones on the same network and settings: No problem.

It is ONLY when you have one genuine one, and one or more clone ones on the same link or network, that you will get big problems cos of the frequency error.

Putting aside the frequency error for the moment, the clones seem to operate just fine - I need to be very clear about that.
So if all you ever use are the clones, then you actually should not have any issues as far as frequency is concerned, as they will ALL be out by the same 37kHz or so, so will talk to each other just fine. :)

Having said that, as the seems to be evidence of fake ones on the market now, I don't trust anything that has been cloned, so the cloned ones could also be causing the lock-up issue mentioned on this thread(or the other one?) by another member here. I fully expect that with genuine units, their problem would probably vanish - I have HC-12's running 24/7 for YEARS, and the genuine ones have NEVER locked up. :)
 

techElder

Well-known member
... I'd better keep hammering home ...
Grogster, I guess you didn't read the actual words of my previous post. The point was that I have mixed crystal HC-12s together in my network and all works fine on my chosen frequency.

... Having said that, as the seems to be evidence of fake ones on the market now, ...
(From thebackshed.com) ... The PICAXE forums talk about people having issues with their HC12's locking up completely ...
You have made some grandiose statements, but seem to have limited research to your own systems (or Phil's one HC-12.) If you have further research, please release those examples of mixed crystal problems.

Also, have you checked your HC-12s at some frequency other than channel one? I've only seen you mention the first channel. I don't seem to have a problem at "C-074."

I know this is hard to produce, because the HC-12 is very popular, but it is incumbent upon you to back those statements up. Please? :D

PS. This isn't a personal attack. Just trying to get to some conclusion, because I don't see any of the problems that you have brought forward from your experience.
 

hippy

Technical Support
Staff member
I have just had five come of ebay from Spain, advert picture shows T300 but 30MHZ arrived so have sent them back as not genuine.
Bear in mind that most photographs for products are merely illustrative or representative and may not reflect exactly what will be received. This can be particularly true for components fitted to a board which may vary in colour and labelling because that can vary depending upon which manufacturer the parts were sourced from.
 

Grogster

Senior Member
Grogster, I guess you didn't read the actual words of my previous post. The point was that I have mixed crystal HC-12s together in my network and all works fine on my chosen frequency.
I was struggling to work out what you meant by that, looking at post #66 above. ;)
Now that I compare THAT post with the post on the end of the last page of this thread, I see what you are getting at.

If you are saying that you have used HC-12's marked with 30.000MHZ AND HC-12's marked with T300, on the same channel and settings, and that they worked for you, you might find that some transmissions work OK, but many will be lost. Try sending more then one, and reasonably close together. In my other forum thread, I state that two different type of modules(a clone and a genuine one) setup the same, will let SOME transmissions through, but in my testing, more then 50% of transmission cycles were ignored by the other end of the link.

You have made some grandiose statements, but seem to have limited research to your own systems (or Phil's one HC-12.) If you have further research, please release those examples of mixed crystal problems.
All I have to go on, are the ones I have here, but so far I have found 13 modules, all marked with 30.000MHz, all of which also match up with the markings as shown on the hc01 website as being clones, and ALL of which are off frequency by the exact same amount. I have no other way to prove past what I have here, anyone else's modules being off - the whole point of these posts is to make people aware of what I have found. I am in no way trying to tell you that the modules you have are bad, only that you need to be aware of the fact that their are clones out there now, as stated on the hc01 website themselves. :)

Also, have you checked your HC-12s at some frequency other than channel one? I've only seen you mention the first channel. I don't seem to have a problem at "C-074."
Yes. In my thread on the other forums, I state that I tried channel 64(458.6MHz), which was the first channel I tried and had the problems with. Discovered that there was about 37kHz error on the clone vs the genuine one via my scanner and frequency counter, so then I reprogrammed both for Channel 1(thinking the same as you), and exactly the same thing - 37kHz off on Channel 1 on the clone too.

PS. This isn't a personal attack. Just trying to get to some conclusion, because I don't see any of the problems that you have brought forward from your experience.
I appreciate that statement. If there is anything else you can recommend I try, I would welcome your comments. :)
Personally, I would LOVE if any members with UHF scanners and suspect modules could test them to see if they too can observe the same 37kHz or so frequency error that I am seeing with my clones.

C-ya. :)
 

PhilHornby

Senior Member
Crystal

I appreciate that statement. If there is anything else you can recommend I try, I would welcome your comments. :)
Presumably, if the "30.000 MHz" crystal is the source of the problem (rather than just being an identifying mark on a problem module), there should be a measurable difference in its operation?

In case it was missed, here is what I measured across a crystal marked "T300" :-

T300.jpg

I don't think I own any modules marked "30.000" and have just recently converted all my deployed modules onto PCBs where they are soldered in, component-side down :(

It's odd that you and I have problems (albeit different), that no one else is experiencing. We do have something in common though - we are both (unusually) using C064 (458MHz), though it is hard to make a connection...

Not being an "RF man", I am slightly intrigued by your frequency measurements ... is 37KHz really a significant difference? (I freely admit to not understanding how FSK communications work, having failed to make any observations using my SDR module that matched what various websites said I should be seeing :confused: )

EDIT

I forgot to ask - are your HC-12's being used at extreme distances? ... perhaps at the limits of their capabilities, which might show up any incompatibility.
 
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reginald

New Member
Bear in mind that most photographs for products are merely illustrative or representative and may not reflect exactly what will be received. This can be particularly true for components fitted to a board which may vary in colour and labelling because that can vary depending upon which manufacturer the parts were sourced from.
Yea but I did send a message with the order that if they were marked 30.000 mhz that I didn't want them but they ignored it and sent them anyway. Since then I have asked two suppliers about the markiings (both show t300 pictures) and one has not replied and the other said read the pdf file !!. I have got a network running at about 500m between my PC and some outbuildings comprising of four modules plus one on the PC. Everything works fine at 1200 baud and I can see the data go back & forth as expected. Use a extra comm port parallel to the PC module on my PC and the none of the four 30mhz mods will receive the data though the network is still running fine swap to the three T300 I have got and they all work fine. I have no doubt that there is a problem if you mix the types. I can reproduce it every time. The only thing I haven't tried is testing 30mhz with 30mhz over the distance because my modules are soldered in.
 

Grogster

Senior Member
Hi everyone. :)

@ Phil: Could I please send you a clone module that is failing the test here, and can you please measure it's crystal? I tried to to do it here, but my frequency counter is loading the oscillator and stuffing up the results. I also have now started soldering the modules in, on the reverse of the PCB with the helical(to protect it, mainly), so it is a real pain. :( I have a 2GHz spectrum analyser, so I will try to measure the crystal with that if I get time in the next few days - assuming you can with a spectrum analyser. I have a feeling that the analyser will also load down the oscillator and give false results, which is why I ask if you can measure one I have here, as you have already done it with working ones on your scope. :)

Re. your 37kHz question - yes, I believe so. For narrowband, the frequency needs to be really, really close to what it should be, or you will miss data packets. With crystals and PLL these days, that is not a problem. WIDEBAND radios would not care about this so much, as they use much more bandwidth when they transmit, and the receivers are usually also pretty wide in their receiving ability, so their frequency can be off quite a bit at each end, but they will still work. Narrowband is a different kettle of fish. The PDF for the RF chip confirms that these modules are indeed a narrowband device.

Re. your distance question - no, about 2-meters apart. I have tried adding distance, as it has been suggested by others in the know, that modules close together can actually misbehave, as the TX RF can overload the receiver in the other one, as the field is so strong. Distance made no difference.

@ reginald: Believe it or not, that is very nice to know - for me, anyway. This means that YOU are experiencing exactly the same issue with mixed modules on the same setting that I am over here. Your testing and module swapping is giving the EXACT same results as I am getting here. I feel better now knowing someone else can indeed reproduce the situation I am seeing. :) I think you would find that the 30.000MHz modules as a pair or network, will work just fine. But mix them with the genuine ones, and you're in big trouble.
 

reginald

New Member
So tonight I took two defunct HC-12 -T300 and took the crystals off. Took two good HC-12-30.000MHZ that won't receive properly took the crystals off and replaced them with the T300 crystals. Guess what they now receive correctly. Straight away no coaxing. Found out the the T300 are made by TCX below is link to a spec sheet for a 27MHZ crystal which is marked as T270 so I guess it is the same as the T300 -30.000MHZ. The only problem now is the 30.000MHZ crystals have no manufacturer mark so I can't get the spec for them. Still shows where the difference is. Perhaps it is the tolerance or the stability.

https://4donline.ihs.com/images/VipMasterIC/IC/TXCC/TXCC-S-A0001530764/TXCC-S-A0001530764-1.pdf?hkey=EF798316E3902B6ED9A73243A3159BB0
 

techElder

Well-known member
Logic tells me the original manufacturer changed part/supplier, found spec problems and dumped them on surplus market. :D
 

PhilHornby

Senior Member
Si4463 Datasheet

The SI4463 Datasheet (1.2) says the following (in section 5.5 "Crystal Oscillator") :-

"...The crystal frequency adjustment can be used to compensate for crystal production tolerances..."

Presumably the cloners didn't bother with this step, when switching to the non T300 crystal. Perhaps they only had a copy of the firmware executable and not its matching source code...
 

AllyCat

Senior Member
Hi,

It might be that the T300 crystals are NOT exactly 30 MHz. I remember when some microcontrollers used slightly weird "off" frequency crystals to divide down to a "perfect" baud rate. The HC-12 also has a micro on-board and probably uses the same crystal for its clock. Maybe the Cloner/Faker didn't realise (or care) that the crystal might not be exactly 30 MHz, or just chose a cheap "micro" crystal rather than a "communications" grade. Also, the load capacitance is usually a crucial part of a crystal's specification and I believe here that it is integrated into the RF chip.

The frequency reported by Phil in #73 is 800 Hz low which correlates to about 12 kHz low at 433 MHz. Perhaps it has just been pulled low by the 'scope loading capacitance, but how accurate is the reference clock in the "Siglent" ?

Cheers, Alan.
 
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