David Kirkby, G8WRB said:
>There is on eBay at the minute what appears to be a very cheap HP
>network analyser, which I guess would double as a cheap power meter too.
I posted this here on June 18, but I am reposting, due to the
interest in the 3570A on EPAY:
I have a complete HP3570A system, which is in excellent condition,
including the 3330B sweeping synthesizer and both manuals. When they
were sold together with a HP 9820 computer, it was called a 3040A
network analyzer. I do not have the obsolete computer to go with it.
The system has GPIB, and I have a complete hardcopy listing of a
3040A operating program in Rocky Mountain Basic for someone who would
like to enter it either into one of the old HP computers or port it
to a PC with a GPIB board.
I don't see that it is needed for most work, however.
I never used the computer with it, as i was only interested in
visually measuring the loss/phase of transmission through filters,
tuned networks and transformers. It is fine for that, very accurate
actually, but as someone pointed out, it doesn't measure VSWR or S11.
To do so would probably require a resistive power splitter and a
wideband (LF at least) directional coupler from Mini Circuits or
other. It would probably be better to use an antenna analyzer for
that function, as the 3040A system is two full chassis and another
for the XY display.
To record the results, one can step through the frequency sweep of
10, 100, or 1000 points, and manually record the numbers for phase
and magnitude of the the transmission response. The nice thing about
the 3570A (and the later 3577A and 3589A) was that it had 1 Meg input
Z, so to use it for 50 or 600 ohm (audio) circuit, they included BNC
terminators to install on the input. This is lacking in the higher
frequency boxes such as the HP8751A, 8753A, and an expensive high Z
input adaptor box had to be acquired.
The specs of the 3570A are 120 dB dynamic range, 0.01 dB amplitude
and 0.01 deg phase resolution. Frequency can be stepped as small as
0.1 Hz for XTAL testing, and the sig gen can output -86 to +13 dBm.
It also does power sweeps in very precise fashion from the same
synthesizer.
I am selling this thing, would ship in three boxes, with a HP120B
series rack mounted X-Y display (like new also) to do quick sweeps
without storing data (for tuning things). $400 or BO and I have
photos available.
73
John
K5PRO
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