[R-390] HP 8640B RF Sig Gen Leakage???

Bob Camp [email protected]
Sat, 12 Apr 2003 16:07:31 -0400


Hi,

Another way to do the same thing is to use a VHF or UHF pager. They are
amazingly sensitive. Back when I was with Motorola they would go over each
new generator with a pager before they would trust it for leakage.

There are two basic ways to get a generator to radiate:

One way is to feed signal back down the supply line. This is fairly rare in
the case of stuff like the 8640. Most of what comes back out the line cord
is fixed frequency stuff rather than the variable output frequency. It can
be a problem in generators that are a bit simpler in design.

The second way for the generator to radiate is a defective shield. It may be
a piece of coax or a coax connector. It probably is a cover plate or push on
cover. After years of maintenance  things don't always get put back on quite
right every time. Also things like emi gaskets get dirty or bent. Eventually
the generator starts to leak.

Here's another thought - Do you have a military version of the 8640? If so
it's only rated for leakage if it's still in the big ugly yellow tub. I
don't know why that's true, but I"m told it is.

    Take Care!

        Bob Camp
        KB8TQ



----- Original Message -----
From: "Randy Zelick" <[email protected]>
To: "Glen Galati" <[email protected]>
Cc: <[email protected]>
Sent: Thursday, April 10, 2003 9:19 PM
Subject: Re: [R-390] HP 8640B RF Sig Gen Leakage???


> Hi Glen,
>
> Here is the routine: I tune up a radio, say a VHF unit, and measure
> sensitivity. Then I disconnect the generator and hook the radio to a small
> shop antenna. Presto - an on-channel carrier. Run the 8640 attenuator to
> zero, or switch off the RF, carrier still there. Change frequency of the
> 8640, carrier gone... switch off the 8640, carrier gone.
>
> Cheers,
>
> =Randy=
>
> --
> R. Zelick email: [email protected]
> Department of Biology voice: 503-725-3086
> Portland State University fax:   503-725-3888
>
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