I have about the same bandwidth now. Over 2mhz. before reaching vswr of 2:1. I will post a thread about some readings I took. All were at feedpoint then again at radio. I found my original issue causing the narrow banded readings.
222, I must have read your post in error. I thought I read your post to state your antenna showed 28.000 to 26.800 mhz = 1.20 mhz for a <2.00:1 bandwidth.
I also must have missed your post saying your BW was over 2 mhz. If I had understood your antenna was producing a 2 mhz BW...I would not have commented. 2 mhz is a little less but near the maximum I see with my real world S4 antenna, plus Sirio claims in their manual that their NV4K should show <>2 mhz bandwidth.
Generally speaking I'm seldom able to measure my BW curves at the feed point as I think is necessary, so most of my Antenna Work Sheets results for real antenna were recorded at the radio end of the coax. This is due to my not being able to measure the BW at installed height, so I'm forced to measure at the radio end of the coax only.
Don't let this BW issue confuse our discussion...it may not be that important, because in all case I think such results make little difference and for sure if our antennas are matched close to correct.
Give me until tomorrow and I'll have some stuff up. Posted on another thread. I'll have heat shrink over all my joints so getting those readings will be hard. But they are a universal fit I think.
Don't let me rush you 222, I appreciate you doing the work and taking the time to post about it.
Don't worry about the tubing sections that you have sealed up. If you took measurements at the time you built the kit and measured the dimensions and did not find any minor discrepancies then don't worry about getting me these dimensions. I know that Bob85 gave me good dimensions, because he went to the trouble of measuring both the overall and the exposed length for each section of the NV4K's radiator, hoop, radial basket, and top hat. He understood that such details for modeling would be important. The section L3 Bob posted is the part that I'm not sure about, and since this length is determined by frequency...the length is important to my default model for CB at 27.205 mhz. That said, I can use your frequency to build a model and then change the frequency producing the proper dimensions that I choose...so not a problem if you use a different center frequency and give me your results.
I'm just trying to verify my model with a real antenna as close as I can to some real figures that I did not generate. If I can get that close to correct, then I will have more confidence in my modeling.
Believe me doing this kind of back and forth is not easy, and I thank you working with me.
Also, the top whip I measured like shown in the sirio manual and I am sure I used 26 1/4" for 27.400.
I didn't question the dimension you use, I just got a different length for the L3 at 26.6" inches instead of 26.25" inches.
So your length sounds about right for the freq you've listed above.
I agree, and just so you know, I don't think it will matter one way or the other for this Eznec model even though the match results may change a little.
The gamma match whip I also checked from where it's exposed.
My model does not include the matching network, and it would make a difference to some of the matching results, but IMO will have very little effect on the performance results.
Just my opinion.
I'll make some better notes and such and make a thread. Might take me a few days to get it all together.
Take you time and thanks again.