This early 1970's "network analyser" is only a small part of a measuring system.
The unit offered is the transmission test part, and was intended for measuring
the transmission properties
of components in baseband and FDM telephony multiplex systems (which explains
its frequency range 50 Hz - 13 MHz).
To make up a full network analysis system this piece of equipment needs to be
complemented with:
- Signal source, preferably synthesized with GPIB interface
(i.a. HP3330 or HP3325, the HP3320 can be pressed into service)
- Reflection test set (return loss bridge)
- Power splitter and switching arrangement to alternately read transmission and
reflection
- Software to read the instrument output data and present it in a rectangular
or polar (preferred) display system
In my humble opinion this would be a very considerable amount of equipment and
work to make up a network
analyser that stops just "south of" twenty meters.
73/
Karl-Arne
SM0AOM
----- Original Message -----
From: "David Kirkby" <david.kirkby@onetel.net>
To: <amps@contesting.com>
Sent: Saturday, June 25, 2005 1:44 AM
Subject: [Amps] Cheap network analyser on eBay
> 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.
>
> The "buy it now" is under $75. Cheaper than the amateurish instruments
> that give "some idea about the magnitude of the impedance".
>
> It's an HP 3570A, which the tucker web site give a bit of info
>
> http://www.tucker.com/java/jsp/doorway_partnoH-P3570A_invid2370.htm
>
> although I think the max frequency is 13MHz, not 500 as stated there.
> Hence the frequency range is a bit limited.
>
> Here's a bit more info.
>
> http://www.tucker.com/images/images_spec/00004350.pdf
>
> The unit on eBay has option 004, which is the GPIB interface, so you can
> read (and often set) the instrument via a computer.
>
> The seller is definitely in what I would call the "doggy" category.
> Although he has over 1000 feedbacks, there are a lot of negatives (94.8%
> positive).
>
> A friend tells me the model number indicates it is likely to be very old.
>
> Anyway, here's the link to the eBay site.
>
> http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=97192&item=7525812615&rd=1
>
> It's clearly not without its risks, and I don't know much about it, but
> on the face of it, the unit would seem quite cheap and useful. But
> perhaps someone knows otherwise.
>
> You could extend the frequency range with mixers and a couple of sig
> gens, but then calibration would be much more difficult.
>
> PS
> If you do buy it, do your homework. Don't blame me if it needs an XYZ
> that is impossible to obtain, or if its dead and the seller will do
> nothing about it.
>
> --
> David Kirkby,
> G8WRB
>
> Please check out http://www.g8wrb.org/
> of if you live in Essex http://www.southminster-branch-line.org.uk/
>
>
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>
>
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