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A Useful ATU Circuit
It uses a parallel circuit for 30 - 80 and a series tuned arrangement for the bands up to 10 metres The mode of operation is selected by a DPDT switch
post 20 Mar 2024
Antenna Transmatch tuner Links →
Tuners in T for antenne filaire
This is a high-pass T-filter consisting of a variable inductance inductor and two CVs. Each of these 2x125pF CVs has a capacity of 250 pF
Tunner per Antenna tipo canna da pesca
Modifica fatta ad un accordatore ZetaGi M 27 surplus
What tuners do
The primary function of a tuner is to present the radio with its specified load impedance
QRP Z-Match
The two variable capacitors are very compact. A simple SRW bridge allows to indicate the best tuning positions and an additional 150 pF capacity can be switched on, to help tuning shorter wires if necessary
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This is a high-pass T-filter consisting of a variable inductance inductor and two CVs. Each of these 2x125pF CVs has a capacity of 250 pF
Modifica fatta ad un accordatore ZetaGi M 27 surplus
The primary function of a tuner is to present the radio with its specified load impedance
The two variable capacitors are very compact. A simple SRW bridge allows to indicate the best tuning positions and an additional 150 pF capacity can be switched on, to help tuning shorter wires if necessary
Antenna switch arduino for icom IC-7300 A solution built around an arduino nano and one of the readily available four relay switching boards
50 MHz preamp Gain 26dB with the BFG135 Preamps for 144 and 430 MHz, for 50 MHz, the BFG135a is a cheap transistor and in my view rather strong. It is not easily damaged by static discharge or RF power. FG connection
30 Volt Computer Power Supply Stack A bonus was that i discovered that these did not need a standby load connected to the supply to keep them running just apply mains power and close the Start lead to ground