Introduction: QYT KT8900 PACKET MOD

QYT KT8900 mod for PACKET

This is a chinese cheap 20W 144/440MHz mobile radio, but have two wrong design thinks to connect friendly this unit with your sound card because them not have a external speaker jack, also the squelch operation is too slow.

A good idea is take the audio signal from the discriminator directly, here you have a opensql signal, a clean and good quality and audio signal.

To make this modification please use the ht9170d chip (used to decode a DTMF signaling) also use empty pin 8 on the mic connector with a 2,2uf electrolitic capacitor to audio coppling.

Step 1: Open the Radio to See the Main Board, and Back Display Board Too.

Step 2: Locate the Ht9170d Chip on the Main Board, Near to Conecctor to Display Board

Step 3: Locate the Mic Conector Exclusive Pin 8 and Install a Wire From This Pin to Ht9170d Chip

Step 4: Install One End of the 2,2uf Electrolitic Capacitor on Pin # 2 Ht9170d Chip (vn Pin) and Another Capacitor End to Wire From the Pin 8 of the Mic Connector

Step 5: The Mod Is Done!, Now You KT8900 Have a Audio Signal From the Discriminator on the Pin #8 (mic Connector)

Reesamble your radio and make wires to your PC Sound card

The signal is clean and strong to your audio input on the sound card

Enjoy! 73



KC0TA (author)2016-12-18

I have a newer model (KT-8900D) which has a 20-pin chip, HM9170. Pin-1 is opposite of your picture and there are some similar features of the main board and the front face board. I have not been able to find information on this IC to implement this mod on the newer model radio. Any help out there? Thanks.

I also have a KT-7900D that might require this mod, also.

rfeigenblatt (author)KC0TA2016-12-18

Hi KC0TA I have only a KT8900 to make test, if HM9170 as inverted position on the board in your radio, look for the pin #2 on your chip and follow my instructable to install a electrolytic capacitor

73, TI2BOX

KC0TA (author)rfeigenblatt2016-12-19

I'm wondering about the compatibility of the HM9170 and the HT9170D. The HM9170 is a 20-pin chip while the HT9170D is an 18-pin chip. I just can't find any data on the HM9170 to verify the pinouts of the device. The KT-8900D has a 2-tone and 5-tone decoder function which may explain the different chip (HM9170 with 20 pins) in my radio. It would certainly help if I could locate a schematic of the radio and/or data sheet for the HM9170 chip. Any ideas on getting a radio schematic?

73, KC0TA

rfeigenblatt (author)KC0TA2016-12-20

I see, really I not have any idea about this datasheet, I think you will find the discrimnator signal easy with a oscilloscope test each pin of the HM9170 when the radio is on RX mode

73, TI2BOX

KC0TA (author)rfeigenblatt2016-12-21

Yes, I agree with analyzing with oscilloscope. I was hoping to make this simple with the aid of a data sheet but, as usual, things I do are rarely ever simple. Thanks.

73, Mike, KC0TA