[time-nuts] HP58504A antenna

WB6BNQ wb6bnq at cox.net
Mon Jul 21 16:45:09 EDT 2008

Hi Jose,

If you trace out the power feed (the bottom direction from the coax connection) it supplies the transistor (most likely a MMIC) and the black 6 legged active device (no idea on it).  The silver square looks like a filter
device of some sort between what you call the transistor and the 6 legged active device.  The silver square has no voltage going to it.

The 30 milliamps does not sound out of range to me, but then I have no experience with the hp system.  What makes you think it is the antenna that is the problem ?  If the voltages appear to be about right (your
statement) my guess would be that the antenna might be working correctly.

So I would not be shorting anything out without getting a lot more information first.  Is there anyone else in your area that has such a system that you could compare with ?

Good luck,


Jose Manuel wrote:

> Hello all,
> I´d like to repair a HP58504A antenna that don´t deliver any output signal. The current is about 30 mA ( I think too high), and the transistor (unknown type) and the MMIC (uPC2749TB), seems to be with correct voltage.
> Does anyone have any experience or data about this antenna?
> I took an inside photo: http://www.ea1px.es/HP58504A.jpg     Can the transistor be identified by the color code?
> Thanks in advance, José, EA1PX
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