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


Chris Moulding
 

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.

Regards,

Chris


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: CrossCountryWireless@groups.io [mailto:CrossCountryWireless@groups.io] On Behalf Of Chris Moulding
Sent: 23 September 2019 21:11
To: CrossCountryWireless@groups.io
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.

Regards,

Chris

_._,_._,_


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Robert, VA3ROM
 

Will you be offering just the based unit for sale for those of us with the older antenna unit, Chris?

In my case, the antenna isn't that old ;)

73,
Robert