I'm currently using a hunk of radioshack twinlead (the stiff, foam filled black stuff) for my QRP portable operations... I have a spool of this:http://www.monstercable.com/productdisplay.asp?pin=81
They call the conductors 12 gauge... they seem bigger to me though, and each is composed of LOTS of tiny copper wires, so this is very flexible cable, and fairly lightweight.
Anyone have any thoughts on how this will perform compared to my current RS cable? I plan to test it out this weekend...
Transmission line losses are mainly due to conductor loss and dielectric loss. For quality transmission lines at HF which typically use polyethylene (PE) or PE foam, dielectric loss is insignificant. For example, Loss components in practical transmission lines at HF
shows that dielectric loss in RG213 is much less than copper loss over HF, and relatively insignificant.
PVC is widely used for insulation of power, audio, and telecommunications cables, and it is significantly lossy at HF.
K8ZOA characterised common ZIP cord (which uses PVC insulation), and the data is in TLLC
. Taking a dipole at 14MHz (say feed point Z=60+j0), and 25m of ZIP feedline, the efficiency of the feedline is about 40%, whereas common inexpensive RG6 TV coax would have an efficiency of around 87%. By contrast with PE dielectric coaxial cable, the conductor loss in this case is relatively high, and dielectric loss is as high as the conductor loss by 30MHz.
See PVC insulated feed line on HF
for a graphical comparison of RG6 and ZIP cord.
So, what you have will work, whatever 'work' means, but it is probably not insulated with a low RF loss dielectric, and losses may be quite worse than using a more conventional transmission line.
Thing is in this case that if you are running QRP, you are already behind an average station on EIRP, do you really want to chuck another 3.5dB away?
Sure it 'works', but the question you might ask is how well.
I don't know the detail of the stuff you have, and so it is not possible to be definitive other than to say that whilst you can't say with confidence that it will work poorly, you also can't say with confidence that it will work as well as a conventional transmission line.