Apache Labs Community Forum

Hi,

I was testing the recording feature of (I am using VAC, not sure this has anything to do with this) Thetis and made an audio clip of someone’s transmission. Then (I went in the dummy at this point as I was merely testing) I play the just recorded transmission and what I saw was odd. The transmit bandwidth as per the Panadaptor was twice the bandwidth that it should have been. Why is that?

JJ

I have not looked into it, but if you playback when not TX'ing then audio presented on both sidebands in the spectral area. If you MOX/PTT then hit playback it should be correct (and correct over the air).

R.

I never use this function myself, but FWIW be sure to have DC blocking turned off, and to have the VAC option set to allow playback.

ramdor wrote:I have not looked into it, but if you playback when not TX'ing then audio presented on both sidebands in the spectral area. If you MOX/PTT then hit playback it should be correct (and correct over the air).

R.

Richie,

My intent is to be able to play audio back to a station that is interested in hearing what their audio sounds like (but in the interest of not causing interference/confusion I went in the dummy load to TX the recorded audio). So, what I was seeing on the Panadaptor that showed the TX bandwidth to be twice as wide as the original signal from the station I recorded caused me to think that there is something wrong with my settings. I wouldn’t want to occupy TWICE the TX bandwidth when I play back their audio.

JJ

w-u-2-o wrote:I never use this function myself, but FWIW be sure to have DC blocking turned off, and to have the VAC option set to allow playback.

Thanks Scott, I will check the current selections on these parameters.

JJ

Perhaps you were running with duplex off (DUP not selected top left), which results in a view something like 96kHz if memory serves. So if you were RX'ing at 192k it would look somewhat larger if you then went to TX mode (as long as DUP is off).

R.

ramdor wrote:Perhaps you were running with duplex off (DUP not selected top left), which results in a view something like 96kHz if memory serves. So if you were RX'ing at 192k it would look somewhat larger if you then went to TX mode (as long as DUP is off).

R.

Thanks Richie, Will check.

JJ

ramdor wrote:Perhaps you were running with duplex off (DUP not selected top left), which results in a view something like 96kHz if memory serves. So if you were RX'ing at 192k it would look somewhat larger if you then went to TX mode (as long as DUP is off).

R.

DUP was OFF.

w-u-2-o wrote:I never use this function myself, but FWIW be sure to have DC blocking turned off, and to have the VAC option set to allow playback.

Where do I find the option to "have DC blocking turned off?" I have not "Bypassed VAC for Recording Playback" (box is unchecked) so I should be fine there.

JJ

JJ4SDR wrote:

w-u-2-o wrote:I never use this function myself, but FWIW be sure to have DC blocking turned off, and to have the VAC option set to allow playback.

Where do I find the option to "have DC blocking turned off?" I have not "Bypassed VAC for Recording Playback" (box is unchecked) so I should be fine there.

JJ

Checked the box and play back works fine!

JJ4SDR wrote:Where do I find the option to "have DC blocking turned off?"

Setup > DSP > AM/SAM

w-u-2-o wrote:

JJ4SDR wrote:Where do I find the option to "have DC blocking turned off?"

Setup > DSP > AM/SAM

Roger that Scott! Will check it out.

JJ