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RE: [linrad] RX2500

Hi Stan and all,

> Any idea of the power requirements for the RX2500 and other LINRAD 
> hardware ?
> RX2500:    + 15 VDC and -15 VDC at _______  amps
> RX10700
> RX70
> RX144
> for planning purposes.
All the units need about 0.6 A each.

My setup runs right now like this:
 +14.7V   2.56A
 -14.8V   2.47A

It may change a little for the RX144. Also note that the current
will increase slightly when a near saturating signal is applied
to the antenna input. With +15 dBm applied to the antenna input,
the goes up by about 70 mA.

There will ba a RXHF also. I have not yet decided any details, 
but it may use a similar amount of power but it may also use about
0.4 A depending on whether it needs an RF amplifier or not.

There is no need to run RXHF and RX144 simultaneously but since
the thermal time constant is pretty long you might want them powered
up continously unless you add phase locking of the local oscillators
to a frequency standard.

My lab power supplies are rated 2.5A. They can not deliver 15V for
an extended period of time because there is a relay that doubles the
voltage fed to the rectifier. The pair of 2N3055 can not manage the
heat continously. This is why I operate below nominal. The voltage is
not very critical. 

I would suggest a power source that can deliver at least 3A continously
and for ever while staying cold.

Some day there might be a TX chain that is doing the same mixing the 
other way. I do not think it will need anywhere near the same power
because IM3 on the transmit side can be much higher. Allowing 1A for 
a TX chain should be plenty - but there is no guarantee there will be
one, and what power it might need. The idea is to make it compatible 
in power levels and intermediate frequencies so one can test rx and tx
against each other to verify that the dynamic range is ok on both.



Leif  /  SM5BSZ