Beware of cheap coaxial cables

[Jon Rosenstiel]

This evening I was attempting to calibrate my ratemeter using a 2mV pulse. I was having a heck of a time getting a clean signal, so I decided to try another coax cable. Made all the difference in the world!

See the attached photo of the offending coax. They may as well have left the shielding completely off! What is this, 30% coverage?

I had 8 more cables of the same type. Threw them all in the circular file. (Trash can)

What do you have to do to get decent cables? Make your own?

Jon Rosenstiel
[attachment=0]Coax cables 002.jpg[/attachment]

[pawinemaker]

I have found that coax cables rated for data transmission (like DS-3, STM-1) are a much higher quality than just about anything else out there. The only problem is finding it at a low price.

[Richard Hull]

30% coverage means the shield is crap!! Most stock cables have over 90% or better. Super RF cables that are double shielded offer over 98% coverage!!

30% coverage means that 2/3 of you shield copper is on someone elses cables!!! (saves the manufacturer copper and you money) 30% coax is like using bare wire in the RF world.

Cables on inputs to preamps are hyper critical and even the best throw triboelectic effects in on charge sensistive amps like the BF3 asnd He3 tube to preamp connections. Heroic effort and no expense must be spared on this particular link in the chain.

This lead cable from the tube to preamp MUST be left motionless at all times!

Richard Hull