Re: Revised versions of VLF/LF/HF Vertical and HF Active Vee antennas

David Cutter

This makes  remote access more tempting, eg from the far end of a field (well beyond practical cables) back to the house using an Arduino and WiFi; not that I'm an expert but it adds to my desire list.

David G3UNA


From: [] On Behalf Of Chris Moulding
Sent: 23 September 2019 21:11
Subject: [CrossCountryWireless] Revised versions of VLF/LF/HF Vertical and HF Active Vee antennas


Recently I was asked by a customer if it was possible to reduce the DC current consumption of the VLF/LF/HF Active Vertical antenna as he wanted to use a solar panel and small battery to power it and a receiver at a remote location.

The original amplifier design used a JFET amplifier followed by a bipolar transistor output stage to match to 50 ohm coax cable. This used over 100 mA so it would take a high drain from a solar power battery system especially overnight..

I've redesigned the amplifier to use a transformer after the JFET amplifier to match directly into 50 ohm coax and to reduce losses in the base unit replaced the Owen splitter with a hybrid transformer. Other minor resistor value changes to reduce current drain from the green Power LED were also made.

As a result the DC current consumption is now down to 15 mA and the RF output and IP3 performance is identical to the original version.

All new VLF/LF/HF Active Vertical and HF Active Vee antennas will now use the revised amplifier. Amplifier and base unit PCBs will be marked with the number 2.





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