[ARC5] Visual alignment of BC-454

[Kenneth G. Gordon]

On 22 May 2013 at 19:31, Dennis Monticelli wrote:

> Ken,
> 
> I would be very interested to view those sweep photos.

I have ONE photo up at the moment:

Go here:

http://www.w7ekb.com/Personal/BC454/BC454IF-1.jpg

The receiver is that 10 meter BC-454 I struggled with a month or so ago.

You will notice some "jitter" on the trace, which I am almost certain is coming 
from my B&K 3025 Sweep/Function generator. It is not a very good piece of 
gear, but it is all I have at the moment, and it does work OK.

The IF bandwidth is quite broad, and the regenerative IF causes that peak 
that you see to the left of the main "hump". Also, the shape of that trace 
shows very obvious overcoupling.

I have set the HP-8640B to sweep 10 KHz, and the limits (above and below) 
points are almost exactly 10 KHz: I am sweeping from a little more than 
1408.5 to 1418.5 KHz. which appears to be centered. This shows that the 
IF's center-frequency is not 1415 KHz, but more like 1413.5 KHz or so.

However, I don't see how that really matters much with this receiver.

I am using the B&K's "Sweep Output" on the back panel to drive the HP and 
to sync the scope. The waveform of that Sweep Output is supposed to be a 
sawtooth, but it isn't a particulary GOOD sawtooth, and the slower I set the 
sweep, the more rounded the sawtooth gets. 

I have the sweep rate set at its highest setting, which isn't very high.

I am going to try to feed another signal generator output to the receiver to try 
to get some sort of moveable cursor to see how wide the bandwidth at the 6 
db points actually is. I think that is going to be difficult to accomplish with this 
setup though.

So, what do you all think of this so far?

Ken W7EKB