Aliexpress 7w PLL exciter (no chip used?!) + external stereo encoder

[BlackBeard]

Hi folks,

recently I found this 80€ 7w PLL exciter on Aliexpress: https://www.aliexpress.com/item/1005003148335583.html
I suppose it doesn't use a single chip for signal generation as it only has one chinch input and no BA/BH/QN chip is visible. The description also clearly states that the input is an MPX input, to be used with a stereo & RDS coder. The PCB says "PLL FM Transmitter Circuit Module V2".
Edit: One review from Poland clearly states that he uses the tx in combination with stereo tool.

I'd like to use it as the base for a rig using the 300w amp from Dutchrfshop (in case no one wants to sell me a rig here ): https://dutchrfshop.nl/nl/eindtrap-modu ... er-v2.html

Also, I wanted to know your opinion on this 28€ stereo encoder which is based off the BA1404: https://www.aliexpress.com/item/1005003186960229.html
Rubbish or usable?

Both units are shipped from Turkey - prices include VAT and shipping.

Thanks in advance!
BlackBeard

[Bton-FM]

I saw those boards pop up on Ali a while ago. Looks very similar to the RDVV circuit with the Dual-Gate FET (the original design). It probably works fine.

[sinus trouble]

Bton is spot on!

It looks like a decent RDVV reproduction which i believe uses a Colpitts oscillator at its core!

The Dutch amplifier is great! However remember that 300w is a hell of a lot of power for those who dont have experience! Not only can it cause serious harm to you in respect to RF Burns!

You will also need to shield both the Exciter and LCD from all that power! I would recommend partioning your enclosure into 3 seperate sections! 1 for Power supply, 1 for exciter and 1 finally for the Power amplifier!

The Stereo encoder is not great but it will work? Also im guessing you plan to use RDS?

In which case? Stereo and RDS will not sync so thats something to bear in mind?

Take a look at the SINUS RDS section where we have discussed this issue!

Good luck!

[BlackBeard]

Thank you very much guys!

The Stereo encoder is not great but it will work? Also im guessing you plan to use RDS?

In which case? Stereo and RDS will not sync so thats something to bear in mind?

Sinus, I looked at your RDS project and find it very interesting! I was actually looking to use the Enigma RDS & SPI stereo coder coder from HF-Electronics. How can I sync both? Would be also a thing if I'd use your RDS coder, right? About the Ali stereo coder: I was just curious about the Ali box
Edit: HF-Electronics also sells the Pira32 RDS coder, seems to have pilot sync included. Maybe the better choice for now

[reverend]

Hi folks,
recently I found this 80€ 7w PLL exciter on Aliexpress: https://www.aliexpress.com/item/1005003148335583.html

If you look carefully at the advert on Aliexpress, it's coming from Turkey and not China, so probably not a Chinese copy.

[Albert H]

The circuit is similar to the Dutch RDVV exciter from some years ago, and if its construction is good, it'll work well. The TSA5511 in the board is the PLL IC, so it will be frequency stable.

The stereo coder uses the BA1404. This will be horrible - don't spoil your signal with something as nasty as that! There are plenty of good circuits around the 'net for stereo coders.

My version of the "Sinus RDS" (see elsewhere on this site) provides the necessary signals for a connected stereo coder - the 19 kHz pilot and 38 kHz switching signal are generated in phase with the 57 kHz RDS subcarrier.

[BlackBeard]

My version of the "Sinus RDS" (see elsewhere on this site) provides the necessary signals for a connected stereo coder - the 19 kHz pilot and 38 kHz switching signal are generated in phase with the 57 kHz RDS subcarrier.

Thank you Albert! I'll have a look at it but I think I'm gonna buy a complete transmitter with stereo & RDS.

[BlackBeard]

Does anyone know something about this amp? It uses BLF177 (maybe a fake one). Runs at 48v and puts out 150-200w. For 103€ it's quite inexpensive.
https://a.aliexpress.com/_mOr5AmI

[RF-Head]

some pirates bought it over here in Nl and always complain about sprogging and running hot and totaly not broadband
Seen a few with burnt stripline on the drain

[Albert H]

Also the transistor needs to be mounted so that the legs are horizontal, not bent down. This massively reduces thermal stress on the device - all semiconductor manufacturers recommend this type of mounting.

The output filter doesn't look right - the coil turns should be separated. The filter capacitors also look to be far too physically small. There also doesn't seem to be a proper, stabilised way of adjusting the gate bias (critical in this kind of circuit).

[BlackBeard]

Thanks for the advice guys!