Broadcast - 3 July 2022
First item this week is a thank you to Peter, VK7KPC for his contribution to the “Winter VHF and Above Field Day” last Saturday and Sunday. He single handedly ventured out into a raging blizzard and set up a remote site at Poatina and later in the day moved even higher up towards the Great Lakes. Well, it may not have been raging or even a blizzard but it was indeed very cold, blustery and a miserable day to be stuck out at a remote site trying to make contacts with softies like me that stayed warm at home. I am sure that “Kay’s Fruit Cake” replaced the “Kendal Mint Cake” to sustain life on this venture. His call sign seems to appear in every event log that I have seen so far, I would confidently say that all contestants that managed to make contact with Peter were very appreciative of the effort that he put into helping get more points on the board for the state. I don’t know of anyone else that was brave enough to make this sacrifice! Well done Peter.
The Wednesday club night was well attended and as usual Peter VK7KPC was first there. After he had carried out the required club room start up sequence we found him ensconced in the heated radio shack, tuning in to the Double Scotch hour, run by Nic, VK7WW. Now to expand on the evenings happenings, I will pass it over to Idris VK7ZIR for a rundown of the night’s other activities.
“One of our members has been downsizing and has supplied a range of items for disposal at our Tech Session. There was a selection of instruments and other miscellaneous items on display. Of particular interest was a plethora of Grid Dip Oscillators with and without coils, including a vintage Grundig GDO, in original case with complete accessories. A professional analogue field strength meter and other TV related kit rounded off the collection. In one of the boxes was a “mystery item”. This took the form of what looked like a vacuum tube with a valve type base and a very heavy steel surround. The end was open with a probe and adjustment rings. The only visible marking was the word ‘Vibron’ printed on the steel sleeve. Most intriguing! After much wondering and mostly vacuous suggestions from the audience, our resident valve specialist Lionel VK7ZLB arrived and took charge of the investigation. Mr. Google gave us no clues as to the origin of the marking but Lionel postulated that, because of its construction, it could be a microwave component. It was therefore left to Lionel to take it and consult his voluminous reference library with instructions to report back to the next Tech Session with his findings. If anyone else thinks they could help us in identifying this item, please notify one of the Committee. Lionel also contributed a piece of computer history for our interest. A massive, by today’s standards, hard drive of 1980’s vintage. Manufactured by Seagate, an ST412, its capacity was 10 MB and it had to have its own plug in ATA interface card. A real ‘blast from the past’. Moving forward, there was the continuing obligatory handheld radio programming with more removal of cranial covering due to non-compatible software drivers.
Andre’ VK7ZAB setup a PC with the large wall monitor and demonstrated Slow Scan TV using the popular programme MMSSTV.
He has been decoding all the images sent via the VK7RJG repeater on the Thursday night nets and then posting these images on the NTARC web site under the “Blogs” menu. As a backup he has also been recording the repeater audio via the PC’s internal sound card using the “Sound Forge” editor. This software is a fore runner to the now popular and free Audacity programme. This audio file can be replayed and using a physical patch cable or software virtual patch from the sound card’s output to input the original images can be decoded again. Andre’ replayed the sound file from the inaugural northern SSTV net and decoded the images from that night for all to see.
Andre’ then demonstrated the procedure for loading photos and your call sign template ready for transmission. He didn’t send the output to a transceiver but used the audio recorder to save it to a file. This was then replayed into the decoder to show the results, a simple way to make a test signal for checking the system. Andre’ used the more modern PD90 mode and then showed the higher resolution PD120 and PD180 modes that are used by the International Space Station for their amateur broadcasts.
Colin VK7ZCF then went through setting up the remote control of rigs through the serial port, now days generally a USB computer interface. A control string is required and is different for each rig, this will require some research, copying of posts and testing. As a starting point for control strings and general information, Phil, VK7ZPD has included some excellent screen shots and configuration information that can be found within the NTARC Discord Channel under “sstv-group”. This information has been added to over the previous month since the local SSTV Net started.
Colin also showed an option where the software can be used automatically to send images as a beacon or receive, store and then replay images as a repeater. These options could be useful for testing. ”
Thank you Idris, it was yet another monumental evening, thanks to all who attended.
Now on to Thursday night, our northern SSTV operators were once again able to join the Southern SSTV Net via VK7RJG in the North on Mt. Arthur and VK7RAF in the South. In excess of thirty five images were transferred via the state wide linkup that started about 7:30pm. By the look of things, a good time was had by all. The great thing for me was that even though I was not able to participate at the time, I recorded the hour or so of audio, played it back later through my MMSSTV decoder software and was able to decode all the images successfully. If you cannot or don’t want to decode the images at the time, then they are available on the NTARC website under ‘Blogs’ or follow the link in the text version of this broadcast.
UPCOMING EVENTS
TestNet and TechNet – Wednesday 6th July. TestNet/CW course on 3.580MHz from 7pm till 7.30pm….and a TechNet on 3.567MHz from 7.30pm till about 8.30pm. Your host for the evening will again be Nic VK7WW.
Club Technical night – Wednesday 13th July. Held at the NTARC Club rooms, 7.30pm until whenever.
SSTV Net - held every Thursday night on the 70cm repeater, VK7RJG and linked to the South via repeater VK7RAF. Conducted from 7.30pm till about 8.30pm. These SSTV images are available on the NTARC website under ‘Blogs’.
Coffee Morning – held every Friday in the NTARC Club rooms. Get warm while you catch up, time is from 10am to noon and we look forward to seeing you all there. These coffee events represent a good opportunity to collect your QSL cards. We currently have cards awaiting collection, so why not pop in and check the QSL box and join us for a cuppa and chat.
FINALLY – A reminder to all members that if you have any items of news you would like added to our weekly roundup, no matter how trivial, then please email them to the Secretary at the following address news@ntarc.net all items to be received no later than 5pm on the Friday prior to the Broadcast.
That’s all folks,
73 from Stefan, VK7ZSB, Secretary NTARC.
