Re: OT: High Frequency coax?? Copper tubing??


Hi Gerry,

Every general class ham should have a coax chart at your fingertips somewhere. Personally I prefer the quickly accessible Wikipedia article on Coaxial Cable at It contains a very detailed chart listing a very large number of coax types and all of the important parameters anyone would need to compare them all.

It says the insulator / dielectric for RG-402 and RG-405 is PTFE (aka Teflon).

Dennis Tillman W7PF

-----Original Message-----
From: GerryR
Sent: Sunday, November 03, 2019 11:15 AM

I'm not at all familiar with this type of coax. What is the core material, and what makes it so good at the higher frequencies?

----- Original Message -----
From: "Dennis Tillman W7PF" <@Dennis_Tillman_W7PF>
Sent: Sunday, November 03, 2019 1:46 PM

These two sizes of Semi-Rigid Copper Coax cable are very common:
RG-402 which is 3.58mm OD (0.141" OD)
RG-405 which is 2.20mm OD (0.0865" OD)

Working with it is very different compared to typical coax we are all used
to. Tools to cut it properly and to bend it properly are expensive. Using
common tools to cut it like a pipe cutter, and to bend it like an
inexpensive bending jig, will almost certainly affect the high frequency
performance of whatever you make.

Dennis Tillman W7PF

-----Original Message-----
From: Reginald Beardsley
Sent: Sunday, November 03, 2019 9:01 AM

Here's a representative link for the information you're looking for:

There's lots more. This was simply the first one google tossed up. It is
great stuff provided you don't want to bend it more than once. Though
rebending used cables is OK. The solder filled braid "RG402" has become my
standard cable for anything above 1 GHz. I've made a couple of H field
probes from a used piece of high grade stuff.

Connector quality on Chinese ebay jumpers is rather variable. I've been
documenting my efforts in this thread:

I will be supplementing the TDR results with 8753B/85046A testing soon now
that I have an APC-7 cal kit and adapters.
Have Fun!
Dennis Tillman W7PF
TekScopes Moderator

Dennis Tillman W7PF
TekScopes Moderator

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