[Hammarlund] Re: Sweep Method for Alignment - different sweep speeds.

[Kenneth G. Gordon]

On 9 Apr 2006 at 14:56, Julian Bunn wrote:

> Regarding the merits of slower sweep speeds, I did a check today,
> comparing the IF response curve when sweeping at 1ms, 100ms, 1s and
> 10s ... there was no discernible difference at all.

I think Andy Moorer explained it quite well: the determining factor is 
NOT the IF center frequecy, but the IF bandwidth instead.

Crank your IF bandwidth down to as low as you can get it, say 100 Hz, 
and try again. You will notice a difference then.

The narrower the IF bandwidth, the slower the sweep speed must be to 
prevent ringing. 

Actually, you can HEAR this ringing even without the sweep generator's 
effects, at tight bandwidth settings with a crystal filter. All of my Heathkit 
rigs which have 400 Hz filters exhibit it. Trouble is, most hams don't 
really know what they are hearing when they hear that sound. And it is 
very clear on a scope.

Ken Gordon W7EKB