[Elecraft] PX3 -- AM Mode Display

[GRANT YOUNGMAN]

No, I’m not missing any points here. Actually LO cut doesn’t really make much sense in this context in any case, just mentioned it.  It simply maximizes the available bandwidth.

The point — is that if one increases bandwidth, one would expect the bandwidth to generally increase symmetrically about the tuned frequency.  Obviously, if the AM detector is intentionally designed to receive only one sideband (plus carrier), aka the K3 sync mode, that wouldn’t happen.  One would not expect increasing bandwidth to both increase the bandwidth AND apparently shift the bandwidth always to favor the upper sideband.  That may not be what is actually happening, but that is what the KX3 display is showing.

So let’s say that IS what happens.  Then by shifting the low frequency side of the bandwidth upward (using the Lo Cut control, etc.) you can get to what looks like a bandwidth band that covers just the upper sideband of the AM signal. But when you do that (try it), the signal becomes pinched and unreadable, and it is not possible to “retune” the receiver to recover copy.

I’m not bitchig here, just trying to relate the odd PX3 display to what the KX3/PX3 is doing.

Grant NQ5T
K3 #2091, KX3 #8342




> On Apr 19, 2016, at 6:49 PM, Nr4c <nr4c at widomaker.com> wrote:
> 
> I think you are missing the point of AM.
> Remember, the extremes are Hi and if you mess with LO Cut doesn't it open a hole at the center?  
> 
> Sent from my iPhone
> ...nr4c. bill
> 
> 
>> On Apr 19, 2016, at 3:53 PM, GRANT YOUNGMAN <nq5t at tx.rr.com> wrote:
>> 
>> Something is funky on the PX3 when the KX3 is in AM mode.
>>