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This category was created to discuss various questions and topics regarding ExpertSDR2 operation.

ТЕМА: Recommended settings/power for FT8/RTTY

Maximum recommended power 16 Окт 2020 08:47 #1

  • sq3rx
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Hi,
What is maximum (safe) recommended power for FT8/RTTY for daily and contest use?
Mek SQ3RX
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Maximum recommended power 17 Окт 2020 12:30 #2

  • tomas
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Hi,
what do you mean by safe?

RTTY uses FSK- and FT8 PSK-modulation. They are both "non-linear" modulation types, so you can run maximum average power from final amplifier stage all the time (if cooling is good enough). What could happen though is that you will overdrive input signal that will cause harmonics and intermodulation, there fore just drive until you get wanted known average power.
My tip is to always check the ALC-meter, the ALC-function should never be active (i.e above "0"). So increase input signal until it increases to just below zero, then you will most probably have a clean and good signal for all activities even with full power from you rig.

73
/T
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Maximum recommended power 19 Окт 2020 12:46 #3

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To go one step further with Tomas remarks:

In order to keep the signal clean, it is very much necessary to increase the TX FILTER TAPS!!!!
The default value of 256 is MUCH to LOW- if you increase the TX filter taps t 4096 you'll notice a much improved IMD - and if your PC can handle it change to 7168

I's suggest setting all the TX filter Tap modes to a minimum of 4096 but preferable 7168 if your PC doesn't run into processing issues

I also set my DSP Filter Taps at 7169 as well

And like Tomas mentioned keep your AGC slightly below o ( around -3 ) for me seems to be a good sweet spot

Now to answer your initial question I am assuming you are asking if the finials in the radio are capable of Full Duty Cycle? That maybe a good question for roman or Vasilly to comment on.

If I ever need more then say 45-50 watts in a digital mode I just use the A1000 at that point I could pretty much set a brick on it and come back tomorrow still keyed up and TXing

Roman / Vasilly if you see this could you comment if sunSDR2DX is capable of Full Duty Cycle TX?
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Последнее редактирование: 19 Окт 2020 12:46 от N8SDR.
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Maximum recommended power 19 Окт 2020 18:35 #4

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tomas пишет:
Hi,
what do you mean by safe?
/T
By safe I mean:
1) Does not overload trx amplifier (I don't want to burn it)
2) Provides clean signal.

N8SDR thank you for your suggestions. I've changed filters taps to 7168 - EESDR2 and Wsjt-x work smoothly. I still don't have idea how to configure AGC. Can you provide any screenshots ?
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Maximum recommended power 19 Окт 2020 20:38 #5

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sq3rx пишет:
By safe I mean:
1) Does not overload trx amplifier (I don't want to burn it)
2) Provides clean signal.

Ok, then I think I answered them above :yes:

good luck!
/T
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Maximum recommended power 19 Окт 2020 21:11 #6

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sq3rx пишет:
I still don't have idea how to configure AGC. Can you provide any screenshots ?
Regarding AGC/output power settings it depends somewhat on your set up, but assuming you are running wsjt and ESDR2.
There are two level controllers, the one on wsjt called "Pwr" and the one in ESDR2 options -> VAC called "TX gain"

1. Start by setting wsjt "Pwr" to mid and "TX gain" to -20dB
2. Set ESDR2 "Drive:" to 0%
3. Right click on signal meter and select "TX" -> "Mic-meter"
4. Press "Tune" on wsjt-x
5. Start increasing "Pwr" and "TX gain" until "Mic-level" is just below zero (lets say -3 to 0) (My settings are full "Pwr" on wsjt and -14dB in VAC, this is a matter of taste I guess)
6. Go back to "power/SWR-meter" on the signal meter as in #3
7. Now you have a good input level and can start increasing "Drive:" to wanted output power.

Dont forget to sett RX-level to approx 50dB in wsjt by adjusting VAC "RX gain"

I hope this helps.
73
/T
Последнее редактирование: 19 Окт 2020 21:17 от tomas.
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Maximum recommended power 19 Окт 2020 23:32 #7

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Thank you, been busy Yes as suggested above, also my setting are very close as well -14 in VAC for both TX and RX gain
I found using those settings what I see displayed on the Power meter in EESDR is very close to what I see on my external meter as well.

if you right click on the BARgarph meter in EESDR you will get a menu popup select show s-meter this will pop out a large analogue looking meter on it watch the mic metering I see around -2/0 which keeps things happy
Please do not email me and ask for help I no longer will be part of this, If I could delete /remove my profile I would do so.
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Maximum recommended power 20 Окт 2020 08:02 #8

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I finally set up my configuration correctly :D . The best result achieved with -5dB TX gain on VAC and -10.5dB level on Wsjdtx Pwr.
Once again thank your for your support.
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