[Lowfer] using HP 3581 or 3586 on VLF / LF

[Roger Rehr W3SZ]

Hello, All!

I saw a reference somewhere (I think) to using HP Signal Analyzers [like the
3581 (for 0-50 KHz) or the 3586 (for 50 KHz and up) ]  receivers.  But now I
can't find the references.

I did find a nice site on using the HP 310 in this manner.

Since I have come back from Dayton with a couple of 3581A's I was hoping
someone could guide me on this.  It seems that I can get two types of output
from the 3581

1.	At the 'output' BNC, I get a signal the same frequency as the original,
but at much larger amplitude (several Volts out from -79 dBm in, for
example)

2.	A signal meant for an X-Y plotter that also up to several volts output,
but at the low frequencies you'd expect for an X-Y plotter.

My thoughts thus far are:

1. 	to use the 3581's as a preselector/preamplifier and feed the outputs
(which will need attenuation) into an existing VLF receiver (then all they
do is narrow the bandwidth and amplify) or

2.	use the pen plotter output to trigger an audio oscillator when the signal
comes above a certain level, thus producing a CW signal.

Are there other approaches people have tried with the 3581A?

How about with the 3586?  How is is done with those?  Is it worth my picking
up a 3586 A / B / C if I find one cheaply?

Thanks in advance.

Thus far there seem to be a good number of 3581A's out there, so I hope they
are useful.  I paid 25$, and 2 of 2 I got seem to work OK.

73,

Roger Rehr
W3SZ   FN20ah
2 Merrymount Road
Reading, PA  19609-1718
http://www.qsl.net/w3sz