[R-390] IF alignment questions and noise issue.

[Roy Morgan]

On Jan 17, 2015, at 10:05 PM, Dennis Wade <sacramento.cyclist at gmail.com> wrote:

> Test Lead CX-1363/U


In the URM-25B manual, I found this:


12. TEST LEAD CX-1363/U.
(See figure 2-17)
a. The Test Lead CX-1363/U should be used for
making interstage receiver measurements. It consists of a 0.1
microfarad capacitor (C-601) in parallel with a 510
micromicrofarad capacitor (C-602) enclosed in an aluminum
case similar to the antenna simulator and fixed attenuator
units. One end of this case is terminated in a type UG-185/U
connector. Two 18" long clip leads extend from the other end.
The capacitor network is in series with the red lead, whereas
the black lead is grounded to the case.
b. The capacitor network is inserted to protect the
attenuator (E-112) of the signal generator from accidental test
probing at points of B + potential and should always be used
when making interstage receiver tests.
c. The reactance of the test lead capacitors should not
normally affect the accuracy of the meter (M-101) voltage
indication since, in most cases, the impedance at receiver
interstage measurement points will be high. It must be
realized, however, that when the CX-1363/U is used at test
points of low impedance (below 400 ohms) the meter
indication can no longer be depended upon to reflect the
actual signal voltage applied.
 

Roy Morgan
RoyMorgan at alum.mit.edu
K1LKY Since 1958