Great video comparing qualities of RF cables

[differenceclouds]

An interesting look into a field where the subtleties of cable design really do make a large difference. There's a bit around 14 minutes in where he compares the frequency response of a well engineered cable and a more generic cable after being twisted around. Not only is it interesting that the frequency response of a cable only a few inches long is so far from being flat, it's also amazing to see that there really is a large difference when the cable is disturbed.

Two overlayed frequency response graphs showing before and after the generic cable is disturbed. Notice the range is from 300kHz to 50GHz:

 

[DonR]

Lack of cable lifters make me doubt his work... Bell Labs or not.

 

[solderdude]

Of course there are measurable differences above 300kHz in cables up to 50GHz.
This is important when transmitting analog signals in that frequency range.
For analog audio... not important at all.
For digital (which is HF) it is kind of important but a 'digital' RF signal is far more robust and less sensitive to error than lets say reception of very weak antenna signals at different frequency(bands).

 

[MaxwellsEq]

Broadcasters have for a century taken a great deal of care in selecting RF cables and connectors and installing them. It is absolutely the case that bending a coaxial cable beyond its specified bend radius has a deleterious impact on its performance at RF. The same is true of fibre.

 

[Mnyb]

In the days of analog televison this was a factor but as solderdude puts it even digital audio is almost DC compared to typical use cases for coax where characteristic impedance and reflections and skin effect actually comes into play . Is not Radar "cables" just hollow tubes with very smooth bend radius's otherwise the signal will literally leave the cable.

 

[fpitas]

Our cables at work are all supported on cable risers to eliminate those effects /s

 

[kchap]

An interesting look into a field where the subtleties of cable design really do make a large difference. There's a bit around 14 minutes in where he compares the frequency response of a well engineered cable and a more generic cable after being twisted around. Not only is it interesting that the frequency response of a cable only a few inches long is so far from being flat, it's also amazing to see that there really is a large difference when the cable is disturbed.

Two overlayed frequency response graphs showing before and after the generic cable is disturbed. Notice the range is from 300kHz to 50GHz:
View attachment 232082

Geek heaven.

 

[kchap]

I mean I'm in geek heaven.