What large ground mounted vertical monpole antenna? 5/8.. 3/4 etc.

[222DBFL]

If need be I will post a thread I suppose. Hopefully this will help someone. It helped me and now antenna is tuned where I want it. And also Marconi, edges of the 2.0 vswr readings were at 26.800mhz to almost 28mhz. Obviously antenna can only be resonant where I tuned it, which was more for the upper portion of 11m band. 27.385-27.400 is about where I got best readings. R=50-52, X=0-2, vswr 1.0:1.0. Now to get it back up!!

 

[Marconi]

222, I hope you kept some measurements you made during construction.

I am curious what is the overall length of your radiator from the very bottom, below the radial hub, up to the tip of L-3, not including the top hat ball.

222, thanks for the added details, but my first question, noted above, was how tall is your radiator overall.

I don't mean to be picky, but I note that you ended up with your L3 measurement at 26.25" inches for 675mm. My calculation for 675mm = 26.6" inches for L3. Is this difference, because you adjusted your new length shorter for L3 to get you closer to 27.5 mhz...that I think you suggested to us in your earlier post was your desired frequency?

 

[Marconi]

222, the reason I'm being picky is because I'm trying to confirm my Eznec model using your analyzer results. I wish to see how close my model results might be to some real numbers we both might provide. I don't own a NV4K to test with so I have to ask others.

I also can not use the tapered dimensions in my models that might duplicate the real antennas construction. This is due to Eznec limitations using taper. So, I have to pick an average dimension for the models radiator and radials. That is a compromise that I can only hope works-out close and without the real antenna to test and measure...again I have to ask questions.

I have all the tubing dimensions including the diameter that Bob85 posted sometime back for the New Vector 4000, but I wanted some confirmation of those dimensions. Bob measure all the tubing lengths as well as the unexposed length use to make the overall antenna length and this is great. I have relied on these numbers for my antenna models. However, Bob's take-off shows 36-3/4" as the length for the section L-3, not including the top hat ball as best I can tell, at 36-3/4" inches. I'm not sure if this is exposed or overall however. I went by the tuning dimension for my model at 27.205 mhz and uses 28.7" inches. For these reasons I requested your overall length in your construction.

222, I don't think any of this will show much of a difference in the models performance values, but it might show me a difference to consider in the matching results my model indicates, and this is only thing I am trying to confirm.

To be clear, in real world testing just using our radios and considering the errors noted above...I don't think we can detect any differences in antenna performance for pattern, gain, or angle.

 

[Marconi]

If need be I will post a thread I suppose. Hopefully this will help someone. It helped me and now antenna is tuned where I want it.......Now to get it back up!!

A thread about your install will be helpful I think.

I made a couple of post above, but you may have your antenna up already. If so, don't worry about it...I'll get the answers to my questions another day.

And also Marconi, edges of the 2.0 vswr readings were at 26.800mhz to almost 28mhz.

The bandwidth noted here is very narrow. I recall DB suggesting your BW was narrow at some point in this thread and I agree. I don't recall seeing this info in your earlier post, but I assume the results note above is for the current setup. Did you take a BW curve reading with the original setup? If so, what was it back then? Was the original BW curve measured with the antenna raised up or at 9' feet? That might also make a difference if we consider a difference in height for those measurements.

I find my Sigma4 is very sensitive to different setups showing a 2.00;1 BW from 1.2 - 2.4 mhz. I'm not completely sure, but I think old theory was that a narrow BW shows the best performance, and maybe more recent theory suggest the best performance can be noted at or near the highest BW achievable.

As usual in the case when theory is being considered, such results seem to typically be minimal in values (very small differences), so this consideration above might not make a big difference in the scheme of things for CB operators. That said however, over time I have had the feeling that being able to measure my antenna setups showing me a wider bandwidth...seemed to result in better performance just as DB suggested, but I must admit that sense could also have been my natural bias at work too.

I recall having a vivid recollection of this BW issue when tuning my I-10K several times in the past. However, Jay the maker of the I-10K also was preaching this same idea in his promotional efforts...so that could have been working on my natural bias.

Good luck and keep us posted on your signal results after you get it raised back up, and don't forget to take a good comparison reading from your buddies that you contacted with your antenna recently down at about 9' feet. Tell us how far away these guys were as well.

 

[222DBFL]

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. It was my 1:1 balun which was about center of my coax where my split is. Replaced with a good barrel connector for now, and will add my Huber suhner surge arrester in line I suppose at some point. But now the antenna is working like it should with a good bit of freq range. 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. They come pre drilled. Also, the top whip I measured like shown in the sirio manual and I am sure I used 26 1/4" for 27.400. So your length sounds about right for the freq you've listed above. The gamma match whip I also checked from where it's exposed. I'll make some better notes and such and make a thread. Might take me a few days to get it all together.

 

[222DBFL]

Also the 2 locals, one is south about 10 miles and the other is close, about 4 miles. I haven't had a chance to speak with any of my other further out locals but was able to hear 675 around Sarasota shooting dx yesterday. I could hear him and the guy he was talking to. My receive does seem better than the tornado or the A99 and signal and audio reports are best they have ever been so I've been told by at least 2 good known sources. Like said I'll post more details in my thread as different type antennas were used, both beam and vertical.

 

[222DBFL]

I was off on the measurement. It is 26.5". And yes it was to get me more toward the 27.5. I ended up at 27.400-27.405.

 

[Marconi]

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.

They come pre drilled.

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.

 

[222DBFL]

No worries sir. For all the help I've gotten from you and a couple of others, I got this antenna figured out and finally tuned correctly. Just bare with my lack of knowledge and I'll get every measurement I can and all my results for freqs, I did take quite a few readings through the 11m band to verify antenna had the bandwidth it was supposed to. I'll explain more why I had to go back and redo some things other than adjusting antenna as well. Again. Thanks for all the help, and I'll get the stuff to you soon. Have a good one.

 

[Marconi]

222, below is a topic from an article in my old (1977) ARRL Antenna Handbook, talking about "Feed Point Mismatches."

The chapter does have references at the end, but this topic is not referenced there. None the less, I believe the ideas in this article were probably resourced from several QST articles by Walter Maxwell who produced the series entitled "Another Look at Reflections," at about this same time.

This describes in simple terms how and why a modestly close mismatch is not as much of a problem, in real world radio operations, as some would suggest.

Sorry the last few lines are cut off.

 

[RadioDaze2.0]

A local breaker has just got one of these:

https://www.vortexantennas.co.uk/shop/q82-vertical-11m/

I look forwards to check his signal out when he comes on next. That antenna looks very like a Sirio Vector 4000. I suspect he will be blowing smoke !

222DBFL can you see any really obvious problems with the Vector for mobile static?

I would probably cut some slits in the tubes and use butterfly wing nut jubilee clips.

I am trying to understand how long and large the lower cone section is and whether that could be transported in one piece or if it is massive ? I think it is taller than a man ?

My interest has been perked in this antenna. I wonder if it can be easily modified so it is easier to erect when static mobile for either ground mount or just a 4.5 meter shortish mast.

I am also wondering if this antenna would be significantly better than a Gain Master in real performance terms.

That Vortex Q82 says it is 2 S points better than a Vector (12dB) ? Anyway if there was anyway to get a Vector together within say.... 1 hour or so I might be up for it. I imagine once marked up with dimensions it would be quicker.

I kind of need something to keep my interest levels up.

 

[222DBFL]

Way too many possible problems for this antenna to even be remotely close to an easy static mobile setup. The bottom hoop section is about 8ft tall by itself. Lots of nuts, bolts and screws and such to get lost as well. And it takes time to put together properly!! I learned that the hard way and still need to adjust my antenna since moving it to its final position. I had it perfect!! And I do mean perfect. At 27.400 readings were.
R=50
X=0
Swr= 1.0:1.
This is before I put it up. After placing it up and getting everything setup, antenna currently has the following readings at 27.400
R=57
X=0
Swr 1.1:1.
With it just like this and the base at 26ft. I consistently can talk out to 70 miles so far. I did talk across the entire state a week or two ago, but that is not an everyday happening.
Anyway, back on topic. It just is way too big and would take you at least an hour or more to setup the antenna. Maybe less if you marked every piece. But there are many more nuts, bolts, screws, and small Allen head screws as well that can easily be lost. I'm sure it could be done, setting one up for static mobile. But for all the effort and possible issues, NO WAY!! You won't gain that much out of it compared to say the GM which just screws together correct?? I wouldn't even consider it!! And I love the antenna, don't get me wrong, it's just made to be put together once and placed up once. But this is JMO. Again I just think there's too many parts to lose!!! Small parts!!!

 

[RadioDaze2.0]

I thought it would be a stretch, looks quite fiddly. Thanks for your opinion.

 

[Marconi]

I am also wondering if this antenna would be significantly better than a Gain Master in real performance terms.

That Vortex Q82 says it is 2 S points better than a Vector (12dB) ? Anyway if there was anyway to get a Vector together within say.... 1 hour or so I might be up for it. I imagine once marked up with dimensions it would be quicker.

I kind of need something to keep my interest levels up.

RD this is my opinion. The Vortex would be a very expensive stretch.

I know others will tell you this antenna or that is better, but I honestly do not find enough difference among all the vertical CB antennas I have...to justify spending more money. You could probably do just about as good with an A99, if DX is what you like to do out in the boonies or on a nice hill, then IMO no other effective antenna is cheaper, easier to construct, mount, and work with...than an A99.

Click on my YouTube video link below in my signature area and see some of my CB antenna comparisons. The videos are not well done, but some might give you some ideas of the differences in signals that I have reported.

If you just want something to do that is related to the hobby, and can be informative...get you a FREE Demo version of Eznec modeling software, and try to learn how to model antennas.