Ed,
I can't answer your question directly because it all depends.
Your preamp has a very low noise figure. If mounted at the antenna, it
will swamp out any losses in the feedline (as opposed to mounting it in
the shack). However, with good low loss feedline, the loss in 25 feet
of coax may not be significant. If you had 200 feet of coax, then you
would likely want to put the preamp at the antenna.
If you do add the preamp at the antenna:
With 24 dB of gain, you may find that the dynamic range of your
receiving system is reduced. That can be increased by reducing the
front end gain of the XV144 - it involves removing the MAR6 amplifier in
the XV144. The instructions are in the XV Owner's Manual.
If you do not currently have the preamp mounted at the antenna, I would
suggest trying the stock XV144 to see if that meets your operating
needs. Should you find that weak signals are difficult to copy, then
add the preamp at the antenna for improved noise figure of the entire
system.
If you add the preamp, it may be beneficial to run a separate RX coax
from the preamp to the XV144 (split RX and TX at 144 MHz) which entails
removing a relay and adding a jumper.
If you are not into extremely weak signal reception (such as EME), then
the XV144 without the preamp may be more than adequate. The typical
XV144 will receive a signal less than -140 dBm above the receiver noise
floor with no difficulty.
73,
Don W3FPR
On 3/13/2014 7:24 PM, Edmund Wright wrote:
I have recently finished aligned and tested an Elecraft XV144 Transverter. I
have an Advanced Receiver Research SP144VDG GasFet 2 meter preamplifier. Its
specs are as follows:
Noise Figure 0,55 dB
Gain 24 dB
Compression +12 dBm
Transceiver Power 25 watts
Should I use my preamplifier between my Isopole 144 MHz vertical antenna and my
XV144 transverter antenna connector? I will have about 25 feet of coaxial
cable between the preamplifier mounted on the antenna and the XV144 transverter.
I will appreciate any comments or suggestions
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