JB>> at 10Mhz I don't think there'd be be much loss over 10m

BL> Ahh, Grasshopper... have you ever heard of resistance besides
BL> dialectric losses? Both of which increase, btw, with thin
BL> cable. Dialectric loss hardly matters below 200 MHz.

JB> I actually dug out a calculator ant tried to figure out the
JB> resistance of this cable, and it's stuff all (about 5.5 ohms
JB> round trip on a 100 m segment) I called that 0.23 db loss, but
JB> in power terms it's twice that, but still less than half a dB 

 The losses for RG-58 per 30m in the Amateur bands is as follows:

Frequency  3.5  7.0   14   28    50    144    220
Loss dB   .7    1.0   1.5   2.2   3.1   5.7   8.2

 Bear in mind that dB is a logaritmic scale and the difference
between 0.7 and 1.0 dB is stuff-all. 3db is half-power, 6 db is
four-times. At low frequencies, losses level off at pure resistance.
Once losses reach 6dB, only one-quarter voltage comes back as
reflection, and termination or not becomes academic.

 My problem with 10-m of thin network cable, is that I should have
been looking at 7.5MHz instead of 120MHz!

JB>> as you say I seen no reason why it wouldn't work with a single
JB>> terminator but I feel it'd need to be a 25 ohm resistor. 22
JB>> ohms would probably be close enough... Hmm I'll have to score
JB>> some T connectors and liberate one of my BNC cables from the
JB>> video lash-up and try it myself.

 The problem is that 10m is too close to 1/4 wavelength, even with
the sending end correctly terminated. 
     
 

--- BQWK Alpha 0.5