Category Archives: Constructions

FM Power Amplifier 88 – 108 MHz with BLY87A, BLY89A, KT920A, KT925B

Posted on Thursday January 2nd, 2020 by lz4ny

A very simple fm power amplifier which can deliver 4W rf power with 12V power supply and BLY87A or KT920A and 20W with BLY89A or KT925B. Continue reading →

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Portable APRS Tracker + Messenger AprSVW

Posted on Friday June 15th, 2018 by lz4ny

Portable APRS Tracker + Messenger
AprSVW – traker for aprs with display Continue reading →

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SSB transceiver – “Balkan”

Posted on Friday January 20th, 2017 by lz4ny

Ето накратко характеристиките на трансийвъра:
– Чувствителност в режим на приемане: не по-малко от 1 микроволт.
– Потискане на неработещата горна лента: 40–45 дб.
– Потискане на носещата в режим на предаване:50 дб.
– Изходна мощност на предавателя около 10W. Continue reading →

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Linear PA without HV trafo – gu50

Posted on Thursday January 12th, 2017 by lz4ny

This is very small and light PA, but with power more of 300W output in CW mode and 500W pep in SSB mode. In the PA there is not trafo for HV. The plate voltage is the quadrupled electrical mains AC voltage. Continue reading →

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Preamp for 2m with BF981

Posted on Sunday January 8th, 2017 by lz4ny

To improve one receiver simply adding an antenna preamplifier proved that is not at all easy. It must satisfy two very conflicting requirements. To improve sensitivity and to maintain the dynamics of the receiver. One excludes the other. Clearly … must compromise, but what? Continue reading →

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Direct Digital Synthesizer (DDS) VFO

Posted on Thursday January 5th, 2017 by lz4ny

This is a continuation of my previous DDS projects. This project uses PIC16F628A and AD9850 or AD9851. PIC16F628A is an 18-Pin microcontroller with 2K byte program memory, it is a FLASH-based and a member of the versatile PIC16F62XA family of low-cost, high-performance, CMOS, fully-static, 8-bit microcontrollers. PIC16F62XA devices have special features to reduce external components, thus reducing system cost, enhancing system reliability and reducing power consumption. Continue reading →

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A universal direct conversion receiver for PSK-31

Posted on Tuesday January 3rd, 2017 by lz4ny

Decode and read text message communications being sent over shortwave amateur radio frequencies. Continue reading →

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DSB QRPP mikro transceiver

Posted on Tuesday January 3rd, 2017 by lz4ny

This is a diagram of a very simple design of micro transceiver 21 Mhz built only 2 ICs (SA612 and LM386) and several discrete components, structures can easily be neglected and another frequency with recalculation and resetting the freewheeling circuit and change a quartz resonator. Continue reading →

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QRP BPSK transceiver in 80m

Posted on Monday January 2nd, 2017 by lz4ny

Благодарение на чудесните възможности на PSK31, PSK63 и компютрите се дава възможност с много прост трансивър с пряко преобразуване който работи на фиксирана честота с кварцов резонатор да се провеждат връзки с множество кореспонденти. Continue reading →

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Mini transceiver PSK – NIKI80

Posted on Sunday January 1st, 2017 by lz4ny

Trx niki 80 to proste i niewielkich rozmiarów urzadzenie nadawczo-odbiorcze przeznaczone do pracy emisją psk w paśmie 80m. o mocy wyjściowej 5W. Continue reading →

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