Hi Martin, Yes I agree that FT8 or any of the Weak signal modes do not imply using low power transmitters.
They are 'what it says on the tin' Weak signal modes. A station on 20Metres in New Zealand could be running a kiloWatt and be a very weak signal here in the UK -- FT8 would be appropriate in those circumstances.
However; The HF bands will always be there, QO100 will not be. Lets make sure it's amplifiers last as long as possible by using sensible power from our transmitters.
Ron
Yes Keith, I could not agree more.
I am now listening to a station who is triggering Leila and yet giving reports of -7 to -14 to stations who are giving him reports of +8 or +9.
He obviously does not have a good receive signal and is trying to compensate by using too much power.
Everyone using FT8 Must be able to monitor their own transmission, or chaos ensues.
Some stations also have too much drift to enable good decoding.
On the subject of Fox/Hound mode, I am not certain that this is appropriate for the satellite. HF operators use this mode successfully for rare DX expeditions but on the satellite, some operators do not understand the correct procedure for QSY'ing.
Ron.
Hi Detlev,
I could not do any sensible measurements at 40MHz because my hybrid couplers are not good enough at that frequency.
So I used a different approach and made a measurement at 50MHz.
The picture shows the 50MHz (+8dBm) carrier passing through a 50.125MHz crystal filter, the filter attenuates the 50MHz signal by almost 50dB.
What is left is the true RMS level of noise passing through the filter, The cursor shows the analyser noise floor at -122.5 dBm.
The Leo Bodnar device noise measured at 50.100MHz is -107dBm.
As to how that will relate to 40MHz I will leave to others. This is my final opinion on the subject.
Regards everybody and stay safe.
Ron.
Detlev, I will have a go, but I doubt my simple equipment is capable of nulling out the carrier enough -- even with a notch.
If I can manage it I will let you know. 73.s de Ron.
OK Detlev.
I must stress that it is not a measurement that I would take to the bank -- HI.
My analyser noise floor is about -125dBm. The measurement I did using a notch at 40MHz
indicates that the Bodnar unit is lower than that. I would quite believe their claim of -150dBC/Hz @ 10kHz.
Just as a follow up of my analyser measurement.
The Leo Bodnar unit's noise floor at 10kHz offset was about 6dB above the analyser noise floor.
The analyser RF bandwidth was 1kHz, the video bandwidth was also 1kHz.
This equates to -100dBC/Hz. But I stress, not a scientific measurement, just using what I have.
Hi George,
As I said in the description below the picture "Not a very scientific test"
The analyser does not have the narrow bandwidth to make any better tests. I might repeat the experiment with a measuring receiver and carrier null -- but I have other things to do ATM.
Regards, Ron.
Not a very scientific test, but here you see the 10kHz offset at -70.16dB
Measured at 40MHz on H.P. analyser.
Glad it worked!
Here are two of my pics.
Have you got a plug in the microphone socket Thomas.
Even if the plug is not connected to anything it will wake up Win10 to the fact that the sound card is now live.
Has given the HackOne a new lease of life...Thanks Alberto!
Further update:
I remeasured the next day and found the sun-noise was 5dB. Looks like I need to reposition the dish!
Just measured 3.0db which is within 0.1 db of last year on my 90cm RX dish.
Before and after filter.
