| Author |
Message |
    
Duck246
Intermediate Member
Username: Duck246
Post Number: 131
Registered: 8-2004
| | Posted on Saturday, July 21, 2007 - 11:17 am: | 
|
What does this look like? This is a Maco V-5000 at 45ft. I believe this means X is inductive right?
26.965 - 1.3 SWR
R= 38
X= 5
27.205 1.2 SWR
R=53
X=11
27.405 1.3 SWR
R=67
X=6 |
Tech237
Moderator
Username: Tech237
Post Number: 858
Registered: 4-2004
| | Posted on Saturday, July 21, 2007 - 2:53 pm: |
|
I believe that X just indicates the reactive component and that it may be inductive or capacitive..
Simon
Tech237
N7AUS
|
Dale
Senior Member
Username: Dale
Post Number: 1022
Registered: 12-2002
| | Posted on Sunday, July 22, 2007 - 9:21 am: |
|
isnt it the R the one to really be concerned about?thought it was ohms?maybe im backwards
dale/a.k.a.hotrod
cef426
cvc#64
|
Bruce
Senior Member
Username: Bruce
Post Number: 4483
Registered: 9-2003
| | Posted on Sunday, July 22, 2007 - 8:16 pm: |
|
I use a noise bridge and it shows R and XL or XC you set the dial untill it nuls out and read the dials ....
On 6 since 66
|
Tech237
Moderator
Username: Tech237
Post Number: 860
Registered: 4-2004
| | Posted on Monday, July 23, 2007 - 8:55 am: |
|
Dale, - no. Yes R is resistive (for DC only) but antennas are not just resistive, except at resonance because they don't work at DC but on AC voltages. When you tune and antenna you are really working at making the R of the antenna match that of the source AND trying to bring the reactance down as low as possible.
Your Resistance can match but if the Reactance is high or unmatched rather your SWR will be high too.
Now having said that some antennas will always have a value of X higher than 0 and in many such cases that is because the antenna needs that to work properly..
Hope this helps - it is a short, simplified answer to what is really a complex question.
Simon
Tech237
N7AUS
|
Patzerozero
Senior Member
Username: Patzerozero
Post Number: 3870
Registered: 7-2004
| | Posted on Monday, July 23, 2007 - 6:23 pm: |
|
resistance 50 ohms, to ALLEGEDLY match the transmitter, with no reactance at the resonant frequency. that said, the perfect 5/8 wave antenna on THE resonant freq should be R=50, X=0. everywhere else will be different. with a few weeks of spare time to play, 'duck, you can get that from your v5000. it'll take adjustments to the length of the radiator, & WHERE you adjust it will change readings you get, as well as length of the ground planes & where you adjust them from as well. THEN, the tuning ring can be affected no matter where you make changes, spacing, where coil is tapped, angle of coil, etc, etc, etc. forget it though, you're close enough! |
