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Phasing two antennas & TX/RX switching – Shed Workshop – 6 October 2019

Bernard ZL2BD will talk to the challenges of switching between RX and TX antennas on your rig and demonstrate a simple circuit (not suitable for break-in keying) to allow us to use our active antenna  or mag loop antenna on RX and our standard antenna on TX (or you can buy one like the MFJ unit above).

He will also demonstrate using a phasing circuit with two RX antennas (through a full 360 degrees) to reduce noise levels.  This can be used with  two active antennas, or in fact, any two antennas.

All welcome at Bernard’s QTH: 1 Winsley Tce, Churton Park. Sunday 6 October 2019 1pm -3pm. Tea and coffee available after the workshop talk.

To whet your appetite you may want to read the following introductory articles:

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Receive Antenna Phasing and Noise Cancelling Explained

1 file(s)   3.66 MB
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Details of circuits for RX/TX antenna switching and phasing of two RX antennas

1 file(s)   1.35 MB
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Shed Workshop 4 August

Bernard talking about fake transistors, discovered during prototyping of the Active Antenna Kit

Bernard ZL2BD and John ZL2XJ launched the first of a pair of shed workshops covering the construction of an active antenna.

Bernard discussed why amateur operators should be interested in active antennas, the basic design elements that underpin the electronics, and the nature of the kit construction that members will be undertaking.

The designs all incorporate a FET followed by a bipolar transistor. They must transfer the very high impedance of a short whip antenna to the 50 ohm input of a typical receiver. They may also include filtering to reduce broadcast interference (BCI). They are fed using 12v over the coax, so they require a filtering system to separate RF from DC back in the shack.

We will meet on 1 September from 2pm -4pm since it will be Father’s Day and some may want to go out to lunch with family. We will be constructing our devices, so members will need to bring a soldering iron. The kits will be provided free of charge to members. If you didn’t attend the first session, please contact one of the committee to confirm you are coming to be sure we have sufficient kits available.

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Active Whip Antennas Explained

1 file(s)   2.22 MB
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Upcoming regional events

  1. Saturday 27 July 9am start – Branch 42 Used Equipment Sale – Onepoto Speed Boat Club (Onepoto Road). For more information contact ZL2ABC (Bruce Packer)  zl2abc@gmail.com  or by phone to 04 938 7147.
  2. Saturday 3 August 2019: 9.30am – noon – Winter DV Talk by John ZL2TWS Start Time: 10:30 am (clubrooms open 9:30 am – morning tea/coffee at 10:00 am). At Upper Hutt Clubrooms Branch 63, Park Street, Upper Hutt.A registration fee of $5.00 applies to cover expenses. Please register with mark@foxtrot.co.nz Finishes no later than 12:00 pm. Learn about D-Star G3 Plus2 and ircDDB variants followed by a demonstrations of BlueDV for D-Star, DMR and Yaesu System Fusion (YSF). Instant D-STAR registration available on the day for new users of Peanut or BlueDV. The talk will then continue about Hotspots and Dashboards. Following the session many of the group will have lunch at the Cosmopolitan Club (pay your own way).
  3. Regional Councillor Meet Up at Branch 42 Clubrooms in Titahi Bay – Date and time to be confirmed – The combined regional meeting will be on either Tuesday 10 September or Wednesday 11 September. Both ZL2 councillors are expected to be present.
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Sunspots … Sunday 21 July 2019

At the Branch 50 event held at Mike ZL1AXG’s QTH on Sunday 21 July, Mike gave a presentation about sunspots – what they are and how sunspots impact on the ionosphere – and therefore on HF propagation, what the next cycle may hold, and their possible impacts on climate.

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Sunspots Presentation Part A

1 file(s)   4.41 MB
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Sunspots Presentation Part B

1 file(s)   2.73 MB