Simon ZL1SWW and Harry ZL1BK did some measurements on “old wobbly” – the 5775 repeater vertical and found it is currently behaving. It has a broad smooth low SWR curve across 2M – quite unlike previous measurements where it exhibited an extremely odd shaped response.
There is probably an intermittent connection somewhere, so even though it currently looks OK, the antenna will be replaced. Harry has completed the refurbish on the replacement and its ready to install. With it being monthly meeting time again, the antenna replacement would have to wait. At the meeting a proposal to establish an AREC group was discussed and unanimously passed. A number of members have indicated their interest in being involved and one early project will be defining and implementing an improved capability for emergency communications from the clubrooms. Five new members were sponsored and accepted to the club.
Dave ZL1DL displayed a “mini” radio interface that is under development. With the current interest in Winlink, Dave suggested a small interface suitable for handheld radios might be useful. Initial discussions with Keith ZL1BQE, who has produced a number of designs, was for an interface “around matchbox size”. Keith suggested such was entirely possible but would comprise mostly surface mount components. This probably wasn’t going to suit the idea of a club assembly project, and so a slightly larger format was settled on. In fact, there are many sizes of matchbox, so the current design is not far off the original brief.
The interface is effectively a USB connected sound card along with a PTT control signal. TX and RX audio and PTT connect to the radio and a USB connection is made to a PC. The current development does not have audio / PTT isolation between radio and PC. This was not deemed necessary for handheld radios, as ground loops are unlikely. However, we are looking to potentially ( or is that galvanically? ) [stop the bad puns – please!] provide for isolation as an option; this will require squeezing in an additional couple of transformers and an opto isolator. Current thinking is we will have a USB-C socket for the computer connection and a 4 pole 3.5mm socket to accommodate a radio specific connection cable. Thanks to Keith ZL1BQE for the ongoing development.
Slightly more than a few visitors turned up today in some fairly impressive transport. Members of the Vintage Car Club had a drive to Musick Point and stopped to admire. We were happy to have a chat and share the history of the building. [Yep the post heading was clickbait!]
