Coaxial cable stretcher

300 divided by frequency equals free space wavelength measured in meters which equals 360° through a vacuum.
Easy stuff really simple math

 

It's not a question of using the scope to measure delay it's a question of understanding what happens within the piece of cable to hinder the Precision of your measurements and use that knowledge to your advantage when setting up your test bench

 

ARRL Antenna Book, 17th ed., p. 24-12:
"When the line length is an even multiple of 90o (that is, a multiple of ? wavelength), the input resistance
is equal to the load resistance, regardless of the
line Zo... It does not matter whether the impedance
...is resistive, reactive, or a combination of both."

There is only one frequency I am concerned with.
I only know one technician who devoted his life to a single frequency .
That's one way to learn some interesting things if you focus your whole life on a single frequency. There is only one frequency my technician is concerned with as well as the majority of his customers.

Check out these hams arguing amongst themselves about this very topic it's pretty funny
http://www.redwaveradio.com/9_dbad721b9a0582f7_4.htm

 

An rf test bench only needs to be configured for a single frequency assuming all the customers use that frequency.

Every rf test bench I've seen except for one has the following problems to varying degrees:

Stability (lack of self oscillation)
Bandwidth
Noise
Harmonic distortion
Intermodulation distortion
Temperature coefficients
Large signal power
Slew rate
Large signal power conversion efficiency
Amplitude frequency response
Phase frequency response
Differential group delay distortion
Pulse fidelity
Overload recovery
Sensitivity to transistor production lot parameter variations

Making the phase angle of the load voltage and current equal is desirable. A complex load impedance produces an elliptical load line which produces distortion even in a totally "linear" circuit.

 

Perhaps you could remind me why your opinion even matters since by your own admission you have never compared your own work to anyone else's work. Keep in mind that's all I've done for the past 12 years. The only thing that matters is real-world performance and not a bunch of theory from someone who by their very own admission has never achieved half of what my equipment is capable of doing at the same frequency which is the only thing that matters. Until you are capable of talking from Drums Pennsylvania to Harrisburg Pennsylvania atwill 7 days a week from a mobile or from Drums Pennsylvania to Quakertown Pennsylvania at will 7 days a week on 11 meters on a.m. your opinion means absolutely nothing to me. The only thing that matters is what can be replicated at will. Anybody can ramble off a bunch of quotes from a book kind of like David Bupp did. Until you understand how cable works at a single frequency and how you can manipulate cable in such a way to render reactance meaningless, and are able to recognize how reactance affect the accuracy of an RF test bench that isn't configured correctly your opinion really means nothing to me.
I spent the last 12 years analyzing work from people just like you and comparing it to everyone else's work and by your own admission it doesn't Stack Up.
When you take two different radios to two different technicians and both radios are identical models and afterwards one of those radios only talks half of the distance and then you take the one that talks half the distance back to the guy who did the good radio if he is able to duplicate the same results from the radio that was less than desirable before in a consistent manner you might be onto something which is precisely what I've done over the last 12 years. Having a very good signal generator with almost no total harmonic distortion and being able to maintain the Integrity of the waveform out of the transmitter is a very difficult thing to do as I'm sure you are aware. Someone that can do it on a consistent basis is someone to be respected.

 

Delay is always caused by the dielectric.
Not probably. Always. The point wasn't to measure the delay. The point was to acknowledge the delay exists. Once you acknowledge the delay exists then you can start to understand other coaxial cable characteristics like 90° impedance Transformers and 180° impedance repeaters.
Once you acknowledge the existence of those things then you can better understand how to present a 49 ohm load to a transmitter on a single frequency on a test bench.
Per Arrl handbook
180° increments of any cable at a specific frequency with any characteristic impedance will always present a 49 ohm load to a transmitter at same frequency assuming a 49 ohm load is present at the other end of the cable Regardles of any reactance present.
And that's precisely the point of any test bench.
For maximum accuracy you always want to be immune from reactance in a laboratory setting.