News Page 12
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SARCNET Goes Digital
We had been listening for weeks on 40m, looking for regular digital teletype-mode traffic (i.e. Where stations can type messages to each other, using a computer, and send them over the air, using an HF transceiver. However, not like FT-8, where messages just contain call signs, signal reports and locations. We also explored JS8 - which was too slow, and VARA - which was not free and had too much TX activity). While digital teletype-modes are common on 20m, to our surprise, there was no traffic on 40m! We were looking specifically for any QSOs using the Olivia digital mode, which utilises forward error detection and correction, which provides virtually error-free communications on very week signals. An Internet search of suitable Olivia frequencies helped, but only one frequency was relatively free of WSPR traffic and other QRM. So, in September 2022, we started a regular digital version of SARCNET on 7072.500 kHz USB using Olivia 8/250. It operates in the afternoons and/or evenings, Melbourne, Australia time.
The settings for FLDIGI are: Dial (QRG) Frequency 7071.500 kHz, Cursor (Centre) Frequency 1000 Hz, Op Mode Olivia | OL 8-250. The settings for your HF transceiver are: Mode USB, TX/RX filters, if you have them, 850 Hz to 1150 Hz. The settings are shown below.
FLDIGI Settings
HF Transceiver Settings
The purpose of the net is just to increase tty-mode usage on the 40m band. As the net grows in popularity it means that stations will not have to be on every day and they can call in for just a short time. We are still experimenting with how to run a digital net on HF! A digital net is not without its challenges: The net control can be passed around as necessary. The net controller can broadcast the order of stations in the net and can update it whenever a station joins or leaves. Conveniently, FLDIGI has macro buttons to automatically send regular text, but these are originally set up for single station QSOs, not a group. Typing is slow and in a net of even a few stations it can be "a long time between drinks" - i.e. waiting for your turn. Hence we have developed the following hints and tips for stations joining our net:
Frequency: 7072500 Hz (i.e. 7071500 Hz Dial frequency and 1000 Hz Cursor frequency)Alternate Frequencies: 7072200 Hz and 7072800 Hz if the above channel is in use.Rig Mode: USBDigital Mode: Olivia 8/250Time: 0700-1200 UTC
Power levels: Generally use low power (QRP), say less than 30W. Indeed, we have made 3000 km QSOs on 0.5W. Note that if you can see a station on the waterfall, it is using more power than is strictly necessary for a reliable Olivia QSO! The net controller should use higher power and call CQ regularly. All stations may like to increase power if a DX station is present on the net.Squelch: Use the minimum squelch level to avoid the display of random noise characters - The net controller will turn squelch off to see weak signals.IDs: Do not encode or decode IDs (turn RxID and TxID off) as these take extra time and cause operational confusion.Spotting: Turn spotting on (click the spot button on the top menu bar) and use PSKreporter to check for Oliva activity.Cursor: Do not change your cursor frequency to centre stations that are not quite on frequency. Use your rig's RIT. Keep your TX frequency constant.Messages: Short, single line sentences are easier to read. Avoid any unnecessary verbosity. In a group, no more than six (6) single line sentences per QSO will ensure that everyone gets a turn.Macros: Use only the Tx and Rx macro to avoid confusion. Leave FLDIGI Call and Op information blank for net operation.
Tx Macro:
<TX>
Rx Macro:
de <MYCALL><RX>
QSOs: Press Tx, type your sentences, type the next station's callsign, press Rx. Simple.Backspace: With FLDIGI you can use backspace if you make a mistake!Signal Reports: RST and SNR reports are of little value. Report the percentage correctly received. E.G. 90% copy.Overs: Start and finish each over with a new line.Callsigns: Only provided at the end of an over, e.g.: VK2DJP de VK3SRCNet Control: A voluntary net controller will run QRO, with TxID on, call CQ regularly to invite others, and publish the net call sign list once every round like this:
CQ SARCNET de VK3SRC,VK2DJP,VK3TET,VK3IK,VK3MKE,AJ8S,VK3TXBreakers:
VK3SRC de VK3AXH
Hi Ian. Welcome aboard. 100% copy. Please pass it along in the list.VK3AXH de VK3SRC,VK3AXH,VK2DJP,VK3TET,VK3IK,VK3MKE,AJ8S,VK3TXNo Breakers:Hi Joe and the group,...VK2DJP de VK3AXH
VK2DJP de VK3SRCHi everyone,...VK3TET de VK2DJP
Station List: Joe VK3TET, Mike VK2DJP, Skip KL7NN, Oscar VK3TX, Keith VK3MKE, Chris VK3IK, Tim VK1TTY, Adrian VK5AW, Andrew ZL1COP, Geoff VK2XGB, Greg WA5IEK, Stephen ZL1ANY, Jim AJ8S, Matthew VK6QS, Rob VK2ARL, Felix VK3FAR, Dick VK7DIK, Karl VK3KRL, Justin VK5LAN, Paul VK2AMT, Mike W4ISB, Charles VK1CM, Colin VK2LCT, Ken JA1RZD, Alan VK4AAN, Simon VK4XP, Daryl VK3AWA, Rob VK6WHO, Gavan VK4GAV, Scott VK1PWE, Ralph VK3ZZC.
Here is an actual record of a small group session from 15 September 2022. Note: FLDIGI shows transmissions from your own station in red:
CQ SARCNET de VK3SRC
VK3SRC de VK2DJP good evening Joe. Can't stay long dinner is in the oven.
Hi Mike,
Could you decode that other station?
He's on regularly but won't QSO.
VK2DJP de VK3SRC
VK3SRC de VK2DJP no I could not decode him.
I noticed that FLDIGI automatically changed mode when you transmitted in Feld.
Yeah I don't like that. I click "Notify Only".
I suppose its OK when there are lots of modes present on the frequency.
VK2DJP de VK3SRC
VK3SRC de VK2DJP
Had a QSO with Ian VK3AXH earlier this evening so there are some other active stations… Build it and they will come!
Yes. That's good.
Have a nice dinner Mike.
73 VK2DJP de VK3SRC
Thanks Joe, Maybe catch you later this evening.
TNX fer QSO Joe, 73
VK3SRC de VK2DJP sk
73 Mike. de VK3SRC
CQ SARCNET de VK3SRC
Good evening Joe and Mike.
QRZ de VK3SRC
Sorry, my laptop was playing up. de VK3TX
Hi Oscar,
How are you this evening?
VK3TX de VK3SRC
Hi Joe, all good in general.
Feeling a bit worse than yesterday but I hope this sickness will finish up soon.
VK3SRC de VK3TX
Yes it is terrible.
Hope you get better quick.
Lots of static crashes.
Doesn’t worry Olivia, though.
She is pretty good at decoding!
VK3TX de VK3SRC
Many thanks Joe.
I noticed today during the whole afternoon the same on 20m, sometimes also the receiver overloading a bit.
I just wanted to say hello today but, I won't be long here. I may try to sleep early,
VK3SRC de VK3TX
That's OK.
We don't have to get on every day, or stay long.
We just need to make a noise to say that we are here.
There is a link on my QRZ page to a page about this net.
Still trying to work out the details.
73, Good Luck de VK3SRC
Looks like for me it is a must. LOL.
I'm really enjoying this, something different.
Always listening for something different but took me 7 years to find someone else interested!
Thanks for the check in today.
Cheers Oscar. GET BETTER mate. 73 de VK3SRC
Before I go, you've neen spotted in the cluster! 73 de VK3TX
Oh no. I better keep my head down, hi hi. de VK3SRC
CQ SARCNET de VK3SRC
VK3SRC de VK3MKE Good evening Joe.
Hi Keith,
How are you?
VK3MKE de VK3SRC
Yes very good. All under control.
I saw your sig so I thought I should say hello.
Also to VK3TX I could see both sigs very well. Btu
Very good.
Mike was on earlier too.
Well this is a lot of fun!
I wonder if anyone else can hear us?
QRZ de VK3SRC
Good, starting to make a presence felt.
Im using another old Codan tonight a 8525 abt 25W this one has fixed channels but its going okay.
Tried a few calls on 20m this arvo but had no responses. Could see some PSK31 sigs as well.
VK3SRC de VK3MKEQ
VK3SRC and the group de VK3IK.
Just a quick call in.
I am runing the club net at 2030. I will be listening .... watching.....LOL.
Enjoy. 73 de VK3IK
VK3IK de VK3SRC,VK3MKE,VK3IK
Hi Chris. Thanks for calling in.
Just pass it on to the next call in the list above and then back to me.
Over to you Keith.
VK3MKE de VK3SRC
Good evening Chris solid signal.
Great to hear from you.
I'm sure many people would use Olivia if there was some more activity.
Anyway I'll try during the day to call on 40m, this frequency, even tried 15m today too.
Btu Joe
Yes anything we can do to resurrect the activity would be good.
Have been on 7105 LSB mostly today.
VK3MKE de VK3SRC
Yes I hear you sometimes on 7105, I was going to call on 17m today but I was unsure about
the frequency. Suggested was 18.101, I think, but that is really close to the FT8 so I didn't bother.
btu VK3SRC de VK3MKE
Yes well FT8 is only 1.5kHz above us here.
I guess no one will be listening if there has been no activity.
Better do my job:
CQ SARCNET de VK3SRC
No one else there.
Yes very quiet.
On 17m FT8 is 18.100 so it could get ugly.
I can see some SSB just below us too. I just checked power out 15W.
I hoped Adrian VK5AW might call in tonight. I let him know the details.
btu de VK3MKE
Not sure if VK5 is in range.
I have had VK4 and VK6.
Amazed that 40m is open locally to Qlivia all night.
It is a whole new ball game.
We have to find out what she is capable of.
VK3MKE de VK3SRC
de VK2DJP
Hi Mike de VK3SRC
Good evening again Joe and hello Keith.
Will put it to Keith
VK3MKE de VK2DJP
Yes that may well be, forgot about that. It certainly is a new ball game for me.
Good evening, Mike nice to hear you again.
There is a website I found that has lots of info on the various modes I'll find it again and mention it.
VK3SRC de VK3MKE in the group
VK3MKE de VK3SRC,VK2DJP,VK3MKE
Yes we need all the info we can get.
QRX Mike...
CQ SARCNET de VK3SRC
nothing heard de VK3SRC
I guess I'll take it now hi hi.
I'm looking forward to seeing just how weak signals can get before Olivia loses them,
I'm running 10 watts at the moment.
Both of your signals are S9 with me.
VK3MKE de VK2DJP
de VK3MKE The website is W1HKJ.com there is lots of stuff there.
Yes that would be interesting Mike, I'm running abt 15W.
I could reduce it a bit further I guess.
I don't know how to express a signal report in this mode but I can copy both of you readable 5 so that's all we need.
VK3SRC de VK3MKE es group
VK3MKE de VK3SRC,VK2DJP,VK3MKE
Always pass it to the next in the list above, then back to me.
The s/n is on the bottom line of FLDIGI. UR 22.5dB Keith.
Great website Keith. What's my s/n Mike?
VK2DJP de VK3SRC
VK3SRC de VK2DJP ur s/n is 22.5 Joe.
Will give Keith his next over.
Running 5W now.
Hope u still copy
VK3MKE de VK2DJP es the SARCNET group
VK2DJP de VK3MKE Thanks Mike,
Yes can still copy.
Joe your s/n varies a bit. UnsurePwhat@to give you.
Just xhduced power to awc%5W too.
btu MK3SR` de VK3MK
VK3MKE de VK3SRC,VK2DJP,VK3MKE
Keith UR 18-20dB and only 90% copy on 5W now.
Looks like that is the limit here - It varies of course.
VK2DJP de VK3SRC
VK3SRC de VK2DJP
Keith 100% copy here with ur 5W
S/N was +8.5 then dropped to -4.9
I think....can't see the plus or minus sign because of task bar
Can't remember how to get rid of it hi hi
VK3MKE de VK2DJP
de VK3MKE
Very good Mike yr signal was as high as 5.5dB.
Joe yrs was 8.8db at th peak.
Just went back to 12W again.
The task bar... can you minimise FLDIGI and then adjust it back maybe VK3SRC de VK3MKE
I don't understand the + and -.
My meter says: s/n: 24.8 dB for you Keith. 30.2 for Mike.
Anyway we are still learning.
VK2DJP de VK3SRC
Keith thanks for the tip
Trying to minimise made everything on FLDIGI come into view.
Joe, when there is no signal the S/N here is something like -15dB.
Signals for the most part are positive.
But they can become negative as the signals weaken and approach the noise floor
VK3MKE de VK2DJP
de VK3MKE Well done Mike.
Yes I don't really get the s/n
I agree about the s/n meter, same here.
If you can copy everything 100% that's ok.
Until I found the cursor needed to be at the end of the text...
I’ll stay for one more round then I'll be going.
btu VK3SRC de VK3MKE es group
VK3MKE de VK3SRC,VK2DJP,VK3MKE
The displayed s/n depends on your RX filter BW.
I have set my RX and TX filters to 850Hz Lo and 1150Hz Hi.
My s/n is between 20-30dB for you guys.
When I set a SSB 3kHz BW it drops to -5dB to +5dB
We can't all set our TX and RX BW so s/n won't be very useful.
Yes I am going QRT on the next too.
Cheers and 73.
VK2DJP de VK3SRC
de VK2DJP
Kinda like how long is a piece of string Joe hi hi
It all boils down to being able to decode the signals
Tonight, you two gentlemen have been 100% copy with me all the time
Yes, it's a good time to pull the plug for me to.
Thanks for being in my shack tonight
73 Joe and Keith, it's been fun again
VK3MKE de VK2DJP sk sk
VK2DJP de VK3MKE.
Yes the old piece of string, 100% copy here too.
I don't have any adjustment on the Codan, except power out.
It's been a pleasure.
Thanks Joe and Mike really enjoyed the chat.
73 cheers de VK3MKE going QRT sk
73 Keith and Mike. de VK3SRC sk
SARCNET @ Warrnambool Hamfest
At the kind invitation of Mark VK3UA, Julie VK3FOWL and Joe VK3YSP, attended the Warrnambool Hamfest. The inaugural event was a joint event by the Warrnambool District Amateur Radio Group and the Portland and South West Radio Group.
Mark said: "It came about from a desire of hams in the Western District to get something happening post lockdown. With restrictions easing, we felt it was the time to organise a local event. With active operator numbers growing in the district, we now have the manpower and enthusiasm to take on an event like this. We hope to provide everyone a good fun radio day."
To support the event, SARCNET donated raffle prizes including an LCD Soldering iron, USB soldering iron and an Electronics Prototyping Kit, valued at $55. It was a great, well-organised, event and good to see so many oeprators attend.
Warrnambool Hamfest