Matching receive and transmit scales

dynamicfusion
Posts: 57
Joined: Thu Oct 14, 2021 5:23 am

Re: Thetis v2.8.11 - UPDATES and current issues

Postby dynamicfusion » Fri Feb 18, 2022 10:37 pm

Is there a way to match receive and transmit display graphs? When I transmit the scale gets bigger, and adjusting the zoom makes it smaller of course, but I can never quite get it to match. I had it matching at one point but did a database reset and cant figure it out. My tune signal is also off center when I tune up, strangely, it used to be in the middle. See attachments:
Attachments
tx.jpg
tx.jpg (199.44 KiB) Viewed 1972 times
receive.jpg
receive.jpg (221.09 KiB) Viewed 1972 times
PD3LK
Posts: 194
Joined: Mon Nov 11, 2019 8:45 pm
Location: Apeldoorn, NLD

Re: Matching receive and transmit scales

Postby PD3LK » Sat Feb 19, 2022 3:40 pm

As far as i know there's no option to couple RX and TX filters or scales. Would be very handy though!
Fasted way that i can think of is dragging the TX filter width wile in TX but it doesn't make the RX and TX scales equal.

73, Leon
Attachments
TX filter wide.jpg
TX filter wide.jpg (1.25 MiB) Viewed 1906 times
73 PD3LK Leon
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w-u-2-o
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Re: Matching receive and transmit scales

Postby w-u-2-o » Sat Feb 19, 2022 4:33 pm

On the frequency axis the TX and RX scales are always in alignment when you have DUP turned ON. Do you have DUP turned ON?

Having DUP on is, IMHO, the preferred method. It shows the actual transmitted signal as it presents itself to RX1 from either the internal RF coupler or an external coupler, if one is configured, as is usually the case when using an external amplifier with PureSignal. With DUP off you are only seeing a representation of the signal at the input of the DAC.

On the amplitude axis you do not want the scales to be the same. At least there would seem to be no compelling reason for that, and every reason not to do it.

When in receive, RX1 is seeing signals that are typically from (for example), -130dBm to -60dBm, give or take.

When in TX, and with DUP ON, the important information is typically between -70dBm and +10dBm, depending on how far down into the weeds you want to go. It's not worth looking that far down, anything that is -70dB or more below the transmitted peak will never be seen at the receiving end.

With such a great disparity in signal levels between TX and RX, to make the amplitude scale cover both ranges is to lose a lot of detail and definition in what is displayed.

However, if you are bound and determined to make them identical, simply go to Setup > Display and make the numbers in RX1 > Spectrum Grid match the numbers in TX > TX Grid Scale.
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pa1hr
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Re: Matching receive and transmit scales

Postby pa1hr » Sat Feb 19, 2022 4:46 pm

Leon,
I notice that you use VAR1.
Try a fixed bandwidth, e.g. for SSB 2.9 kHz.
73, Hans.
--

73,
Hans Remeeus (PA0Q/OE3JRC)
https://pa0q.nl
"Communication is about people, the rest is technology"
PD3LK
Posts: 194
Joined: Mon Nov 11, 2019 8:45 pm
Location: Apeldoorn, NLD

Re: Matching receive and transmit scales

Postby PD3LK » Sat Feb 19, 2022 6:55 pm

learned something new today :) I never noticed before that DUP has the desired effect.
Thanks OM's! r/Leon
73 PD3LK Leon
dynamicfusion
Posts: 57
Joined: Thu Oct 14, 2021 5:23 am

Re: Matching receive and transmit scales

Postby dynamicfusion » Sun Feb 20, 2022 4:13 am

THANK YOU! DUP for the win!

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