I'm not really looking to "press the crowd" for a solution.... it's just that I have never seen anything like this before... and I am just throwing it out there to see if it "rings a bell" with anybody.
A friend has (I believe) a "made for the US Navy" Harris UR-94.
Both sides of SSB seem to transmit fine and push up to decent power........
HERE comes the weird part....
When you throw it at AM.... and you look at it in the spectrum display of a nearby SDR on a computer.....
The carrier is there.....
Te UPPER side information is there.......and looks good.....
The LOWER side information... well... it is there... but only about half the amplitude of the UPPER side info.... AND it tends to "trail off" on the left end.... towards the noise floor.
It is almost like (this is just me trying to describe it!).... the carrier and upper side info are getting through.. but the lower side info is in the "skirts of a filter" and is being "shaved off" or "attenuated".
I stuck a screenshot of his photo... you can see that... to the right of the carrier... the upper side data looks good.... and the yellow in the waterfall on that side is nice and bright.
But if you look at the right... it starts out at about the mid-level.... then just fades (as the modulating frequency goes up). And note that the yellow in the waterfall on the LEFT side is weaker and falls away more quickly than the RIGHT side......
I double checked him.... and this IS AM...... just him modulating the mic.
It doesn't seem like an "audio EQ" problem or it would be attenuating on both sides of the carrier.
It just looks like a filter skirt is sitting JUST to the LEFT of the carrier and cutting the lower half off.
Like I say, I am just looking for a "ping" to see if anyone has ever seen anything like this.
Bob
A friend has (I believe) a "made for the US Navy" Harris UR-94.
Both sides of SSB seem to transmit fine and push up to decent power........
HERE comes the weird part....
When you throw it at AM.... and you look at it in the spectrum display of a nearby SDR on a computer.....
The carrier is there.....
Te UPPER side information is there.......and looks good.....
The LOWER side information... well... it is there... but only about half the amplitude of the UPPER side info.... AND it tends to "trail off" on the left end.... towards the noise floor.
It is almost like (this is just me trying to describe it!).... the carrier and upper side info are getting through.. but the lower side info is in the "skirts of a filter" and is being "shaved off" or "attenuated".
I stuck a screenshot of his photo... you can see that... to the right of the carrier... the upper side data looks good.... and the yellow in the waterfall on that side is nice and bright.
But if you look at the right... it starts out at about the mid-level.... then just fades (as the modulating frequency goes up). And note that the yellow in the waterfall on the LEFT side is weaker and falls away more quickly than the RIGHT side......
I double checked him.... and this IS AM...... just him modulating the mic.
It doesn't seem like an "audio EQ" problem or it would be attenuating on both sides of the carrier.
It just looks like a filter skirt is sitting JUST to the LEFT of the carrier and cutting the lower half off.
Like I say, I am just looking for a "ping" to see if anyone has ever seen anything like this.
Bob