HLLY 20W User Manual

HLLY ELECTRONICS (Hongkong) CO., LTD

The User manual of the 20W FM Transmitter

Thank you for selecting 20W FM RADIO STATION BROADCAST TRANSMITTER.
HLLY-20W IS FM A STEREO TRANSMITTER which apply PLL technology，so it’s

transmission is very stable.

HLLY-20W main board adopt the PLL FM Transmitter IC of ROHM (BH1415F)，
BH1415F build in PLL、Audio aggravation and Low Pass filter, The control board is made of
AT89C205 and AT24C02, the HF amplifier is made of 2 2SC3355、1 2SC2053 and 1
2SC1972,add up to 4 grade circuit。The board adopt HF two layer PCB design，and the shell
is made of wonderful aluminum，the whole little machine is very beautiful and easy to use!

HLLY-20W is design for amateur Radio fancier and not a professional transmitter!

FTechnical Criteria：

1. POWER ：DC 9-->15V(RECOMMEND 12V)

2. WORK CURRENT：<2.3A

3. Preset FREQUENCY RANGE：88—108MHz(Center Frequency:97Mhz)

4. FREQUENCY STEPPING：0.1MHz

5. FREQUENCY STABLING METHOD：PLL

6. Measure of FREQUENCY Stability：LOWER Than 1KHz

7. MODULATION Mode：FM STEREO

8. Frequency Excursion：75KHz

9. HF Output Power：20W

10. Antenna Impedance：50Ω

11. Reference transmit range：2Km—4Km

12. S/N (stereo)：>40db

13. Stereo Resolution ：-55dB ( 100 ~ 5000Hz)；-45 dB ( 5000Hz ~ 15000Hz)

14. Frequency Response：40KHz~ 15 KHz±0.2dB (立)

15. Degree of Distortion ：<0.3%

16. Modulation Degree ：15%

17. Input Level：-15dBV

18. Machine Weight：600g
Machine Size：121×45×154mm

1 Method of Application

1. Link the 50 Coax cable to the “ANT” --(BNC Type）， Be sure the link is stable；

2. Link the audio input to the “Audio” --3.5MM Stereo socket；

3. Link the DC POWER module to the “ POWER”--6.5mm POWER socket ( DC

12V(current >2A) Pay Attention to the power polar ：inside positive; outside negative）。

4. After electrified,the frequency is the one of last power off。

5. Frequency Increase Control ：pull the button“UP”， every pull can increase 100KHz，

pull the button for more than 1 second，the stepping jump to 1MHz.

6. Frequency Decrease Control：pull the button“DOWN”，every pull can decrease 100KHz，

pull the button for more than 1 second，the stepping jump to 1MHz.

SUsing Essential：

HLLY ELECTRONICS (Hongkong) CO., LTD

1. Please select high quality power module like switching power supply。

2. The voltage of power module must not higher than 15V .

3. Please do not alter the frequency when the transmitter is working because it may disturb

the wireless communication.

4. The distance between the transmitter and antenna should be more than 5 meter because

antenna may disturb the transmitter。

5. Recommend using GP antenna or J type antenna, Make sure the SWR(standing-wave

ratio)of the antenna lower than 2,otherwise the transmitter may be damaged because of

the superheating of power tube, attention the frequency of the antenna should match the

frequency the transmitter, Do not use simple antenna, otherwise the transmitter may also

be damaged because of the superheating of power tube!

0Simple Failure & Resolve Method：

Failure Phenomenon Reason Resolve Method

Short Transmit Distance 1 Antenna link failure Check the link of antenna

Short Transmit Distance 2 Frequency is too low or too high Reset the frequency

Short Transmit Distance 3 The power failure or low current Check power module

Frequency display failure Been strongly Disturbed

Power off the transmitter and
power on after 5 second

Audio Distortion

Bad audio input or too high audio
input

Check the audio input or turn
down the audio input

OTransmitter covering Distance（Reference: kilometer）

Receive sensitivity

0.2uV/12dB

Transmit

power

0.1～0.20W

Transmit

power

1～2W

Transmit

power

3～20W

Transmit

power

10～30W

Transmit

power

30～50W

City

0.1～0.5 0.5～1 1～2 3～5 5～8

Town

0.2～0.6 1～2 2～3 5～8 8～10

Environs

0.3～1 2～3 3～5 8～15 10～30

Widen Plain

0.5～2 3～5 8～20 10～30 20～40

Sea communication

1～3 5～15 10～30 20～40 20～50

★Only for reference, also the covering distance is concern with the antenna and environment。

¶FIGURE：