All PSK modes most recent 24 hours

This is on 40m:

Screen Shot 2018-11-14 at 12.46.06

Last update: 14-nov-2018 12:54

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FT8 on 9-nov-2018

The habit is to run it for one or two hours around the morning greyline on 40m, transmit power around 50W, but the bandwidth is only 50 Hz in 8PSK mode.

Screen Shot 2018-11-09 at 10.45.01

The pskreporter.info website produces these statistics.

Last update: 9-nov-2018 10:48

Running FT8 on shortwave

During the last month I was active on FT8 on 20, 40 and 80m, you need the WSJT-X software and there should a way to control the CAT interface plus that you need audio input/output to your PC, so for this I use the microham keyer II. With FT8 the audio level should be such that you just keep the ALC a zero (this can be arranged both in WSJT-X and on the MK2), also the power level of the PA in your transceiver should be at roughly 1/3 to 1/2 of what the transceiver can handle. All advanced options in the FT-991 should be off, don’t use DNF or DNR, no equalizer and no speech processor. Also the bandwidth should be wide open, 3200 Hz is the maximum. This is what I got over the last 24 hours, pskreporter.info is able to produce these graphs.

Screen Shot 2018-11-05 at 10.16.32

My conclusion is that there is nothing to complain about FT-8, this mode is highly resilient and can deal with local QRM, your transmit power can be low, you don’t make spoken noise in the house which is a source of complaints, the FT8 digital mode is very efficient because of its small bandwidth and due to the FSK modulation characteristics. I’m pleased with the interaction time, QSOs are quickly realized, for me it is like hamradio. I’m also pleased to see that FT8 on 40m is in the frequency range where novice amateurs can use it. The only drawback may be, you need a computer so that it would be an extra device to carry in the field if you like backpacking.

The pskreporter.info website produced the graph, it also draws your antenna radiation pattern. The most interesting periods to work in FT8 are around the greyline. The ADI file that is generated by FT8 is manually imported in ham radio deluxe after a day or so, and I will confirm all QSOs on eqsl and lotw. Soon there will be updates to WSJT-X with even a more interactive mode called JS8CALL. (Please read the comment of PE4BAS) As soon as the beta testing is done (I’m not participating) I will take a look at it.

Last update: 5-nov-2018

BER in BPSK

The bit error rate in bi-phase shifted keying modulation is simulated in MATLAB in the following way:

% digital modulation tester (works with large arrays and stides)

l = 10000000; % number of symbols to generate by stride
m = 100; % number of strides
clear xx; clear yy1; clear yy2; jj = 0;
for ii = -20:10:130,
EbNo = ii/10; ber1 = 0; % ber2 = 0;
for kk = 1:m,
ber1 = ber1 + digitanal( l,EbNo,1 );
% ber2 = ber2 + digitanal( l,EbNo,2 );
end
if ((ber1 > 0) & (ber2 > 0)),
jj = jj + 1;
xx(jj) = EbNo;
yy1(jj) = ber1/m;
% yy2(jj) = ber2/m;
end
EbNo
end
% semilogy(xx,yy1,’o-‘,xx,yy2,’o-‘)
semilogy(xx,yy1,’o-‘)
xlabel(‘Eb/No in dB’);
ylabel(‘BER’);
grid

where digitanal is as follows

function [ber] = digitanal( l,EbNo,type )

% this is for BPSK and QPSK actually

EbNoReal = 10^(EbNo/10);

if (type == 1), % BPSK
s = (round(rand(1,l))-0.5)*2;
n = (1/sqrt(2*EbNoReal))*randn(1,l);
r = s+n;
symbols = sign(r);
check = sum( (s == symbols) );
ber = ((l – check)/l);
end

if (type == 2), % QPSK
s1 = (round(rand(1,l))-0.5)*2;
s2 = (round(rand(1,l))-0.5)*2;
n1 = (1/sqrt(2*EbNoReal))*randn(1,l);
n2 = (1/sqrt(2*EbNoReal))*randn(1,l);
r1 = s1+n1;
r2 = s2+n2;
symbols1 = sign(r1);
symbols2 = sign(r2);
check = sum( (s1 == symbols1) & (s2 == symbols2) );
ber = ((l – check)/l);
end

end

It gave me this:

berbpsk

So, a Eb/No of 4 dB results in a BER of 0.01, which seems compatible with the analytical equation.

Last update: 3-10-2018

40m Deltaloop

Here is the 40 meter version of the loop antenna, the aluminum mast is 10m tall, base of the delta loop is elevated at 2 meter with the help of two support poles at the end. The analyzer showed that this antenna is resonant at 40m and 15m, including all odd harmonics of 40m. Although it is not-resonant at 20m I could easily tune it, even got some nice QSOs out of it. At the center of the antenna baseline there is a 1:4 guanella balun, it is described earlier in this blog.

Thanks to John who helped me with this mast, next time I will try this with the 12m carbon fiber stick and perhaps more lightweight wire.

Last update: 28-sep-2018

Panadapter for your rig

Linking everything together

In this setup, the SDR receiver and the PC are a panadapter for the transceiver, a FT-991, but in principle it should work for any transceiver:

  • Install SDRConsole and omnirig on your PC, get microkeyer¬†(or similar) and run it, define three com port COM1 for the radio, COM2 for PTT and COM3 for the mirrored CAT interface. Here we need COM1 and COM3
  • Tell SDRconsole that there is an external radio, via view -> select -> external radio.
  • When you turn the external radio on, it wants to run omnirig, specify here the COM3 port and speed of the mirror CAT line.
  • In my case I also want to use ham radio deluxe, for HRD you go via tools -> 3rd party serial port the connection, here you select mirror CAT port COM3.
  • No virtual audio cables are required, the only thing the SDR does is to listen to its own antenna, the transceiver works with the longwire antenna, SDR console has an option to automute when you transmit, home -> automute is where you need to be.

In the end you should be able to do this:

  1. The SDR and the transceiver exchange all CAT information via COM3, HRD uses COM1 and MK2 takes care of the mirroring between CAT ports. Use the MK2 debugger to check it.
  2. Rotate the frequency dial on your transceiver and the slider on the SDRconsole moves around, also mode changes are transferred.
  3. And the other way around it also works, all actions in the SDRconsole control the transceiver.
  4. You can still use HRD, the logbook receives the correct frequency and the modes via the main CAT or COM1.

See: https://forums.hamradiodeluxe.com/node/42831

Last update: 22-Sep-2018 1:07 AM local