Vintronics - SJV

[Novaro]

I have hopes the chip is rda5820!

[EFR]

So its one of these with inbuild soundcard.

[EFR]

Hmm, yes. Power it from conputer, get audio drivers work and wire these tx and rx pins to an cheap TTL-usb adabter and fuck around with AT commands, You MIGHT get RDS out of it.

[EFR]

https://www.diyaudio.com/community/thre ... ic.342722/

[Novaro]

The one you posted above have 3 ics and clearly the fm chip is 8027 the one i ordered has only 2 ic's.

This is the ad of another seller - No spurious in RF output!

[EFR]

I ordered one also, was quite cheap at 24€ to shipped here.

Ebay shipping page says that I get it around june/july

[radionortheast]

You have to careful with those little lcd ones, they usually have an 8027, I got a dds module it took ages to come, it turned out to worst than a lot of fm chips, people say dds is the best but this wasn’t. I guess you’ll be waiting whatever you get though, results may well be disappointing, your going to have mess about reducing the rf down increasing it for an amplifier for these lcd ones that are been posted, with the 5/7 watt kits they have an amp, you have to be careful they don't spur, others have mentioned not sure they always contain an 8066. I suppose were no closer when this topic started I guess

[FMEnjoyer]

When I now read "No spurious in RF output!"

I just think I have seen that before and it is not so. QN8027 is the worst of the worst.

QN8066.. Albert says is not good. We must assume this is what they changed the 5/7W PCB TX to.... from the QN8007. QN8066 is current you can see the number on the chip on images of the board



There is a fascination with these chips but we now know things.

1 You may not get what is advertised

2 There is mis selling, components, coils numbers, even circuits change without warning or prior information

3 If the better chips QN8007 QN8066 are used then amplified they often skimp on the filtering meaning sprogs anyway

4 if they use the worst chips there is often more filtering but the low spec chips in case of spurs/harmonics means no amount of filtering seems to work to make them good.

Either way they are no good. So it is lesson learnt really. It is as everyone in the know has said don't use them beyond in your car and if you do you will bring trouble fast. A real case of so near yet so far, it looks really neat and tidy and hopes are high and they must sell 1,000's of dollars of this rubbish a month.

[EFR]

Nah, I just did order it as toy to mess around.

24€ shipped to my door is cheap, so I dont fall high even if it is POS.

[FMEnjoyer]

I think those QN8066 PLL boards in photo above are €28 shipped on Ali which makes to 194mW rig shipped in 6 months, rather less good value at €24. Is someone walking from China ? QN8066 on the photo above should be kind of ok spurious and harmonics, certainly not the very worst chip and 6 coils on the output must do something you would have though, but Northeast says they are not so good so we have to trust it.

All comes down to if it is 194mW clean if you get a super clean output for €24 that would be useful, however I suspect with the trend these are mostly garbage that trend will continue, especially when we do not know what chip it is, I keep my fingers crossed for you it is not the QN8027.

[EFR]

Coils at output mean almost nothing, what if chinese engineers did calcullate that lowpass filter to cut at 200Mhz to save space on board and use less turns on coils to keep price of wire down? There is still coils, but it is useless. If they run just lowpass filter, what happens when mixing results from PLL reference oscillator and VCO leak out to band, like that 50Mhz sprog from QN8027 rigå, it also needs an highpass filter then.

And due bad desing or layout, now we push 1-2W power to heat these coils and capacitors at filter.

Designing an transmitter is much more than just filtering output, keeping it clean from first audio stage to last power amplifier, and getting board layout right is the key to success.

Overmodulation, PLL noise, leaks from PLL reference oscillator to VCO, VCO phasenoise (seems to be bad on these chips), harmonics generated in amplifier stages after VCO, harmonics generated in last amplifier, noise from mains or poor choice of one transistor/fet and desing layout and one stage oscillates..

There is so many ways to ruin one simple rig, thats why im sceptical about these "everything on one chip" transmitters.

They are fine in mW levels, broadcast music around house or in car.

I just like to test diffrent cheap chinese RF thing, I know allmost 99% of these suck.

About that shipping time, its always 1-2weeks from china to capital city, then multiple weeks to get nearest postal office. Local mailcarrier wont get any money from parcels arriving from china, so they dont hurry with them.

Fedex, DHL etc is about week from china, but shipping cost starts from 75€ and goes up fast.

[FMEnjoyer]

Sure they are all bad, you proved it for us. 8 days to UK normally for free.

Ok coils mean nothing I was wrong again.

Maybe postal services depend on volume, I bet no one buys from China in your country. You have modern electric cars with air con and lights on the front with a modern radio, we have old that need FM senderz from 2000. We like making ourselves poor cause have no brains.

[EFR]

Nah, just huge diffrence between peoples salary, I personaly drive old 2004 diesel SUV, rearseats removed and registered as van, owned by my "company", legal taxfraud here.

Folks here order shitload of stuff from china, last week news did tell that its about 77000 parcels/week.

Due my limited english skills, (I didnt spend that much time in school, I started to work at age of 15), one way to explain that mail delay is like this: You build red and blue houses, you get paid by how much You build these red houses(national mail like bills and newspapers), but You also have to build these blue ones (parcels from china) when You might have some time to do something to them.

If I order some carparts from Rockauto, its 2-3 days from USA to customs, 1-2weeks from customs to my door. And thats only about 420km...

Windshield wiper blades are here around 15-20€ each, ordered from Germany to my door, 2-6€ each.

Parts for 100W AM transmitter are about 50-75€ sourced localy, around 15-25€ if I use bigger supliers like Mouser. Beer is around 10€ for 0.7L on local pub, 0.33l can is around 1€, about 30€ for 24cans.

If you want quess where I live, drop it to the private message

[FMEnjoyer]

This transmitter on QN8066. I have a such. Quality of a sound is not pleasant to me.

The volume from the sd card is too high, you can use 2 resistors at the input from the 3.5mm jack between left and right to ground this reduces it alot. There is volume through the display if you use the jack, there are two jacks one is for a microphone, I think on mine the colour coding was the wrong way round, make sure its the right input, you do want to be careful with the volume as it can start the inbuilt clipper.

I had one of these I took out the ouput stage, walked around a mile away left my radio recording back on home, with a wire aerial above and below in a black box, I could hear it very weakly, obviously much better when I tried it the other way round. It fascinated me for quite a while with the sd card it starts transmitting straight away, never considered doing anything of this nature before, thought of course you can just use it with the 3.5mm jack, suppose thats how it would usually be used, will work much better from 12v. The 2nd one I had the output stage was in-tacked, a bypassed the 5v regulator, unjusting the biasing the output did come on abit, power them off a few aa or aaa batteries, it could work directly off of a little solar panel the angle had to be correct, so no transmission if the sun isn't shining. The results not great with the other thought, I didn’t bother anymore they are very interesting devices though, make sure you turn down the rf if your getting one.

I am having a bit of trouble to understand this... did you remove the output transistor to run low power ? Then went for a walk with the transmitter with you with wire for an antenna ? And it works off 3 volts I thought they are 12v. I wonder what the trimmer thing does on it ?

Amazing you could hear it 1 mile away with just a bit of wire hanging out your pocket.

[Novaro]

Nah, I just did order it as toy to mess around.

24€ shipped to my door is cheap, so I dont fall high even if it is POS.

Received the unit today! The fm chip is 8006!!!
It is a chip from 2009.

[EFR]

Nah, I just did order it as toy to mess around.

24€ shipped to my door is cheap, so I dont fall high even if it is POS.

Received the unit today! The fm chip is 8006!!!
It is a chip from 2009.

My ordes has left china about 5 days ago, and no updates on tracking yet.

[Novaro]

My order was placed on 14 Jan and i received the item today.

https://www.google.com/url?sa=t&source= ... R1Z60mVzqu

The datasheet of QN8006

[Novaro]

It is working very good. Very nice sound quality i could say broadcast quality.

Inside a box but the cabling need work

[jvok]

Lmao what a mess. Looks like they were trying to use up the scraps of wire they found on the workshop floor

[Novaro]

I was pretty sure the board will not work for some reason so i just soldered everything i found in front of me . Finally worked and the second step is to make it better. I maybe fit an amplifier board and LPF after that. I am just waiting EFR to receive the board and test it.