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RE: [linrad] RX2500

Hi All (probably Leif)

I am building the power supplies needed in hopes of having an
RX2500 for myself.
Is there any danger of component damage if one of the supplies
fails in some way? Either one or both could go to some combination
of 0 volts or +24 volts, so I want to make the power supply failsafe, but
only if need be.

73, Jim Shaffer, WB9UWA.

On 30 Jul 2003 at 2:11, Leif Asbrink wrote:

> 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.
> 73
> Leif  /  SM5BSZ