Resonant Frequency and Tuning my Antenna...help?!?

[8113 Northern MN]

Ok. So a user on this website who i will leave unnamed unless he says it is ok for me to do otherwise, was extremely generous and allowed me to use his AA-54 Antenna Tuner. Ive read complete through the manual and needless to say am a bit dumbfounded. Ive figured out the whole SWR and range settings but other things have me baffled.

In looking for my antennas Resonant Frequency. From my understanding the resonant frequency is the frequency at which I have the absolute lowest SWR and the highest dB return loss (please correct me if I am mistaken). I was extremely surprised to find that my Imax 2000 is returning with 22.248 as that spot. I was led to believe that it is tuned to be used for 11meter and should be lowest within the 27mhz range.

My questions:
Does shortening or lengthening the coax to the antenna change the resonant frequency?
What exactly am I looking for to make sure I am getting the absolute most out of my antenna?
I use 38lsb the absolute most, should I attempt to tune it for 27.3850 and if so where do i start?

 

[The DB]

In looking for my antennas Resonant Frequency. From my understanding the resonant frequency is the frequency at which I have the absolute lowest SWR and the highest dB return loss (please correct me if I am mistaken).

That is a commonly held belief, but the low SWR point does not always mean resonance. The X value determines weather or not you are at resonance. You want X = 0. Unfortunately, if you are using the equipment through a feedline, the variables X and R can and usually does change with feedline length. That analyzer does not have the ability to tune out a feedline length. There are ways around this, however.

My questions:
Does shortening or lengthening the coax to the antenna change the resonant frequency?

The antennas tunes resonant frequency does not change with coax length, however, what your analyzer measures will. Unless the match is a perfect match the feedline will act as an impedance transformer of sorts.

What exactly am I looking for to make sure I am getting the absolute most out of my antenna?
I use 38lsb the absolute most, should I attempt to tune it for 27.3850 and if so where do i start?

To get the absolute most you are using the wrong tool. For that you need a field strength meter. However, using an antenna analyzer like that you can get close. What you need, if you can't make a measurement at the antenna itself, is a feedline cut for a half wavelength at that frequency.


The DB

 

[8113 Northern MN]

So, making my coax from the radio to the antenna the length of one half the wavelength of 27.385 should change my resonant frequency to be around the right spot?

 

[The DB]

So, making my coax from the radio to the antenna the length of one half the wavelength of 27.385 should change my resonant frequency to be around the right spot?

Don't forget to factor in the coax's velocity factor ignoring this will throw everything off. Its hard to cut an exact length but it will be close enough.


The DB

 

[hotrod]

i would only cut coax as last resort. unfortunetly tuning for lowest swr isnt the same
as resonance as stated earlier.if ya friend has a mfj 259b antenna anylizer or similiar
tune so x=0 on your channel of choice.second LOSE the antenna tuner a properly tuned antenna dosnt need it. even a antenna thats a little off still dont need it.as stted earlier
lowest swr doesnt mean all power is getting out or resonance

 

[Marconi]

8113, here is a simple video for using a field strength meter that DB mentioned. Maybe you can get some ideas about the use.

IMO, this is not as easy with a big old 11 meter antenna as this video suggests using a high frequency antenna.

 

[Tallman]

8113, here is a simple video for using a field strength meter that DB mentioned. Maybe you can get some ideas about the use.

IMO, this is not as easy with a big old 11 meter antenna as this video suggests using a high frequency antenna.

Good video for a first timer doing a test like this, or even an old timer like me.