antenna reflect verses swr..

[Splash1]

i never realy understood the reflect feature on my swr meter..i added a mfj line isolator to the coax with a small jumper and the swr went up a tad from doing so but the reflect reading stayed exactly the same,n maybe even a little better,,reads almost nothing..which is more critical,reflect or swr ? what does the reflect reading actualy mean ?

 

[GnG8d]

CLICK

 

[RatsoW8]

I'm not so sure you're using the meter correctly.

The reflected (REF)power reading should be the SWR measurement. In one position (usually FWD or Set) you key up and set the meter for a full scale reading. Unkey the radio and set the switch from FWD(or set) to REF (or SWR). Key the radio again. The REF position is usually the SWR reading.

 

[W5LZ]

Exactly what do you mean by "reflect"? There's some confusion with that word. It actually refers to the power being reflected back from the antenna because of an impedance mismatch, which is measured as SWR. The higher the amount of power being 'reflected' the higher the SWR. SWR is computed by the relationship between forward power and reflected power. So, if the SWR is low, then odds are that the amount of reflected power is also low. If it isn't then there's reactance present in the antenna and the SWR meter isn't telling the truth anyway.
So, what are you referring to when you say "reflect"? If you're talking about that mysterious 'reflection' thing that you hear batted around, then I have no idea what it is. I also think that the ones you hear talking about that stuff, and it's not related to SWR or a forward and reverse reading watt meter, they don't know what they are talking about either.
- 'Doc

(that's the nicest way I can think of to put it.)

 

[Splash1]

the meter is a diamond sx-200..the far left switch is the power settings 200..20..5..watts....the next switch is.. power..calibrate..swr..the far right switch is ref..frw..off..now,, to ck swr u cal then hit swr n u get the swr..to ck reflect u move the switch up from forward to ref n u get the reflect reading which is almost always,or should be lower than the swr reading..ps,,not all meters even have a reflect feature..the instructions did say there is a difference between swr and reflect readings but did not go into detail what the differeces are so thats why im asking..

 

[IMD262]

The reflect position measures the reflected power.

 

[Captain Kilowatt]

The FOR/REF switch allows you to measure how much power you have going to the antenna (FOR) and the REF position shows you how much of that power is being reflected by the antenna back to the radio. By looking at those two power levels you can compute what the SWR is by using the proper formula if you wanted too. Your SWR position basically does that computation for you and shows you directly what the SWR is. As the SWR goes up so does the REFlected power as compared to the FORward power.Some people like to use the REF meter when using an antenna tuner as it shows when you have a good match much quicker that recalibrating the SWR meter while tuning the tuner.

Good meter BTW. I have the Diamond SX-1000 for HF/VHF/UHF and then some.

 

[Splash1]

Kaptin K..thanks for the info..so i guess what your sayin is the ref switch is just used for another way to figure swr ?

 

[GnG8d]

(1+ sqrt (P rev/P fwd)) / (1- sqrt(P rev/P fwd))

 

[Captain Kilowatt]

Kaptin K..thanks for the info..so i guess what your sayin is the ref switch is just used for another way to figure swr ?

Sort of but not quite. Anytime you have even a slight SWR some power is reflected back to the radio by the antenna. This is shown as refelected power on the meter.

(1+ sqrt (P rev/P fwd)) / (1- sqrt(P rev/P fwd))

This is the formula I spoke about above but was too lazy to look up and too tired to pull it from memory. That is how you compute SWR from using the values of forward and reflected power.