mfj 259b x= /R=

[The DB]

where's the popcorn... dang have'ta go to the store for more... Wait! I got 'Rice-Chex', that'll do...
Okay, carry on...
- 'Doc

Enjoying the show?


The DB

 

[W5LZ]

To a point, yes, I'm enjoying the show.
That 'show' consists of the continuing ignoring a fact that has been pointed out several times in this thread. Since that 'fact' is a fairly simple concept, it's not enjoyable that it's ignored because it's the -"accepted"-, or -"standard"- way of doing things.
- 'Doc

 

[hotrod]

I can confirm this. Before I got my first analyzer I used a field strength meter to tune antennas. The peak field strength was rarely at the 1:1 SWR mark. In mobile setups I don't think I ever remember seeing it peak at 1:1 SWR, it was always somewhere else. I would always tune until it peaked and then began to drop off, then set it back to the peak. Later when I bought my first analyzer I noticed that the field strength peaked near as makes no difference to the X=0 reading.

Yes, SWR can make a difference, no argument there. However, once you get past a certain point gains to your signal from making it lower drop out significantly. If I get x=0 and R between 25 and 100 (2:1 SWR) I'm generally happy. If R is outside of that range on a mobile antenna I look for a potential antenna problem, be it positioning or an issue with the coax or antenna itself...


The DB

thank-you 4 your help. my numbers are within what u put up.and too all who enjoyed the show .YOUR WELCOME!!!!!

 

[HomerBB]

If anyone has an interest, or an answer, what difference would be expected to be seen on mobile installations where the antenna was on the roof but one was a magnet mount and the other a puck mount?
Until after Christmas when I can get my MFJ-259b sent in for calibration I can't experiment to find an accurate answer myself.
I personally suspect different results can be anticipated for the two different antenna setups because of the capacitive bonding between the magnet mount to the roof metal that is not present in that way with the puck mounted antenna. Yes or no, and why. Any theoretical info with empirical evidence? (I live very close to the Show Me State)

 

[hotrod]

If anyone has an interest, or an answer, what difference would be expected to be seen on mobile installations where the antenna was on the roof but one was a magnet mount and the other a puck mount?
Until after Christmas when I can get my MFJ-259b sent in for calibration I can't experiment to find an accurate answer myself.
I personally suspect different results can be anticipated for the two different antenna setups because of the capacitive bonding between the magnet mount to the roof metal that is not present in that way with the puck mounted antenna. Yes or no, and why. Any theoretical info with empirical evidence? (I live very close to the Show Me State)

id be interested.as i thought about getting a wlison roof mount.imho id think you would
see a difference. however it would be just minuminal. jmho

 

[The DB]

If anyone has an interest, or an answer, what difference would be expected to be seen on mobile installations where the antenna was on the roof but one was a magnet mount and the other a puck mount?
Until after Christmas when I can get my MFJ-259b sent in for calibration I can't experiment to find an accurate answer myself.
I personally suspect different results can be anticipated for the two different antenna setups because of the capacitive bonding between the magnet mount to the roof metal that is not present in that way with the puck mounted antenna.

I think this would be worthy of being a whole new thread. I am also curious to hear think the difference would be as well.

Yes or no, and why. Any theoretical info with empirical evidence? (I live very close to the Show Me State)

From someone who lives in the show me state I love the addition of this line to your post... Anything I would post would be theory. I could dig up a field strength meter. I don't have a or a magnet mount with a proper stud mount on it to do that test, nor do I have an antenna aside from a 102" whip to use for the test... Even if I were to do the test, the stud on my vehicle goes up through the metal of the vehicle into a 6" riser. This riser would change the effective overall length of the antenna. I suppose I could put a replacement on the stud to hold it in place if I needed to. If someone nearby has a better setup for the test I am happy to show up with a field strength meter...

I could also advise further by suggesting the testing of several different sized magnet mounts if possible.


The DB