To 7/8 or NOT to 7/8, that is the equastion

[222DBFL]

Yes sir. Dx is picking up. Been hearing it on the dipoles. Just a few more things to do to new mast setup and should be able to get to at least 20ft at the very very least. Plans are to go to 24-27ft. Will see when antenna arrives and I am overwhelmed by the difference between it and the 2016 or even the tornado LOL! From photos I've seen anyhow. I will make it work one way or another. But it has to be safe! That is the main goal. M0GVZ, thx for all your replies. I've been listening closely to all of the replies I've gotten and it has helped me tremendously!!! Thx all!! Will hopefully have antenna by Tuesday and up by next weekend. Maybe it's time for an 11m DX contest, hint hint.

 

[Marconi]

Attached below are 4 Free Space models with pattern overlays for my 26.8' foot New Vector 4K model with dimensions set to specifications. All I did was change the radiator lengths to the other 3 lengths noted in this thread by Needle Bender for comparison.

31.6' for a 7/8 wave Saliut
29.6' for a .82 wave
27.7' for a .75 noted for the Sigma 4 length
26.8' for a .75 noted for the Sirio NV5K length.

I posted the 4 overlays, one for each radiator length in order to more easily compare the gain and angle results for each antenna being discussed.

The active Primary pattern starts with the 26.8' model and it is noted in black ink. The others are in different colors and are made active using the ( * ) beside the description.

Attached below are the supporting models and overlays. Just click on the file: IMG.pdf

The note "watch this area"... is IMO the area of the antenna that is ill-effected by making the radiator longer than 3/4 wave. It looks to me to be the reason we see the angle go higher when we add extra length to the radiator. I can't explain why these Free Space models show to be contrary to reports by others, but maybe NB will check this trend out for us when he does his real world testing and reports back.

Note: If we just look at the Free Space gain for these models and don't consider the maximum angles they produce...we might get a totally different idea for the results.

NB, a while back I responded to your request for some model results as noted above. I think you were telling us at the time that you were going to do some comparison testing using a New Vector and/or a L150-Saluit antenna you had, and that you were going to modify and compare signals for these antennas at the various overall radiator lengths noted.

Whatever happened to that project?

 

[Needle Bender]

NB, a while back I responded to your request for some model results as noted above. I think you were telling us at the time that you were going to do some comparison testing using a New Vector and/or a L150-Saluit antenna you had, and that you were going to modify and compare signals for these antennas at the various overall radiator lengths noted.

Whatever happened to that project?

Hi Eddie, I've been fighting some damn bronchial nightmare flu while having to move everything in 2 storage units into one larger 10x30'. No extra energy to play musical antennas until I'm feeling better & done with playing musical storage units. I've decided to assemble the old one to Avanti spec and leave the NV4K stock - for now. the hub on the Saliute busted so I'm stuck ordering another from Sirio. I am anxious, however, to see what I think about the 29er, and I don't mean MountainBike
Another thing keping me somewhat distant from the forum is a dead computer so, for now, I'm stuck on this dang coby tablet, a fate worse than DEATH!

 

[Marconi]

Before I posted my question to you I had a thought that somebody said something about flu, but I couldn't recall who said it. Sorry you have that miserable bug. I know it is no fun. You need to be careful and get your rest.

Sorry, but since I'm too old to do this type of work anymore, I was just getting impatient to hear you report on the performance results you get with your New Vector 4K. Your ideas to real world test the NV4K using different length radiators is of interest to me, and you may be the only one I know with such a similar interest in such comparison testing.

Get well soon.

 

[222DBFL]

How the heck do I start a new post? I would like to at least post my findings and dimensions and issues I ran into.

 

[222DBFL]

So far at this point with the NV4K I have the following readings at height of 26-27ft to base of antenna.
R=59, X=0, vswr 1.1:1, freq=27.405. I had it perfect on Sat. with readings of R=50, X=0, swr 1.0:1, at 27.405. I had a bit different reading the next day, just slightly, R=52, X=3, swr 1.0:1. I messed with the gamma match like a Dumb Ass!! Stupid move. Lesson learned. I should have left it alone. I also changed out mast pipes. Antenna now sits inside new pipe instead of on the side. Thankfully I can reach the gamma match with the 1st section let down I believe from my chimney top. I also used rubber grommets made for lmr400 and ised them to isolate coax from mast from top to bottom. All joints were heat shrank, no-ox used on all joints, and connection points minus coax. Antenna came out great. Looks very nice to me and I don't foresee having any issues with it breaking. Sirio did a bit of beef up at the joints and it does help keep the antenna from bending. Anyway, here are a couple of pics and as soon as I find out how to post an actual darn thread, I'll post here for now. Also here are the measurements that I used in the photos below. Hopefully they will help someone. I've more Marconi, these are the ones I have latest given to you. I will re measure gamma match again when I move it to try to get R back near 50, while keeping X at 0. Or at least close to that. Anyway, pics below. More to come when I figure out how to post my own thread. Good day to all!!

 

[Marconi]

Look for the big black button on the right of the screen: "Post New Thread."

 

[Needle Bender]

Before I posted my question to you I had a thought that somebody said something about flu, but I couldn't recall who said it. Sorry you have that miserable bug. I know it is no fun. You need to be careful and get your rest.

Sorry, but since I'm too old to do this type of work anymore, I was just getting impatient to hear you report on the performance results you get with your New Vector 4K. Your ideas to real world test the NV4K using different length radiators is of interest to me, and you may be the only one I know with such a similar interest in such comparison testing.

Get well soon.

Ahhhhhhhhh, FINALLY finished with consolidating 5 storage units into ONE! Now I can get to the more important business of playing antennas

- How's everything on your end Marconi?

Hey 222DBFL, I haven't checked for your new thread yet and it's been a month since I've been online, how's the R? - Back down to 50-52ohms?

I really should get a new hub & gamma for the Saliute but maybe I can cut a piece of copper and make a copy of the NV4K gamma, just hope the Avanti & NV4K gammas were basically the same.

So..., the COBY tablet met with an abrupt ending - MAN I hated that thing! I'd be in the middle of posting and would have to go back a line or three to make a correction and the dang thing would not come back to the bottom no matter where I clicked.
It got the boot heel and now permanently resides in the local landfill!

So it looks like I'll be back on the roof this week/weekend, playing with my aluminum tubing.
73

 

[222DBFL]

I've not had a chance to mess with the antenna itself NB. It's either too windy, raining, or I have been working!! At any rate I did add a 9ft coax jumper with a Huber Suhner surge arrester and a couple of n-male to SO239 adapters. Now readings at radio are as follows at 27.400.
R=48-49
X=2
VSWR= 1.0:1.
With my dummy load which is a 100 watt 50 ohm Bird dummy load I see the following readings with the MFJ attached directly to the load, only having an adapter inline from Din Male to N-male.
R=49
X=0
VSWR: 1.0:1.
Now with this said, for now I have gotten the R value to a place where I am happy with using my radio. I've made quite a few contacts and have been getting some good reports locally as well. I have confirmed talking out to 70+ miles south of me, 36 miles north of me. And to 60 miles west of me. These are all consistent contacts, or daily guys I talk to. I did also manage an across the state from east coast to west coast of FL early one morning when the noise levels were low. The antenna has handled some heavy winds for a while now and has had its share of some bad T-storms, and the readings above have remained exactly the same to this day. However long ago that I encountered the issue. When I get some time, most likely after the holidays, I'll get the gamma match moved to where I beleive it should be and it should correct the issue. At any rate I am truly happy with this antenna and it has out performed any other antenna I have had or have up currently! It has great RX and TX capabilities and will tune flat if you take your time!!! This is my first go round with an antenna like this and yes I hit a couple bumps, but like I said I am happy I have the antenna!!! It truly does rock. I've had several locals ask if I had changed radios or added power or dofferent mic as the setup I'm running just sounds good I guess. Icom 746 with the vector 4000 at 26ft to the base of the antenna.
Thanks for all that helped and still are!! I will get the antenna tuned properly and hopefully will be able to get rid of the added coax jumper but keep the surge arrester. At any rate the antenna is working and it's making me contacts and I am enjoying myself. That is what matters. Will keep everyone updated as soon as I can get to resolving the issue for sure though. For now the band aid is working..

 

[Needle Bender]

Sounds like you're right there, but it would be nice to not require the patch cord.

What I like is setting the antenna for X=0/1, 1.0:1 & R=50-52ohms, THEN after it's up in the air, seeing the same readings at the radio end of the coax.
- I find if I cut the coax to multiples of a 1/2 wave, ( making sure to use the Velocity Factor in my calcs) I'm not disappointed.

 

[222DBFL]

I have some playing to do. I know I can get it right. Just a matter of having the time and weather. It works well and gets out better than the sirio tornado or the A99, that is for sure!! I have been really impressed with the antenna and some of the locals have really taken notice to the way my radio station sounds and works now. I know it sounds weird but it's what I've been told by more than one local. At any rate thanks for the replies and hopefully you will get yours up one day.

 

[Needle Bender]

I have some playing to do. I know I can get it right. Just a matter of having the time and weather. It works well and gets out better than the sirio tornado or the A99, that is for sure!! I have been really impressed with the antenna and some of the locals have really taken notice to the way my radio station sounds and works now. I know it sounds weird but it's what I've been told by more than one local. At any rate thanks for the replies and hopefully you will get yours up one day.

Ah, so You've tried the Tornado... What's the difference in performance compared to the NV4K, and what's the difference in installation? (height, coax type/coax length, etc.)

 

[222DBFL]

Height, coax, and install are all basically the same. The tornado was about 1ft higher at the base.
Performance wise, the NV4K beats the pants off the tornado!! I am able to talk out to 70 miles consistently in all directions. This has been confirmed by me logging the distances. 50-70 miles is my range and I am only about 9ft above sea level where I live. Maybe a touch more but not much. Anyway. Just my experience thus far. Also dxing has become a joy. The NV4K has logged me some contacts that I have never heard before and also getting me better signal reports all around. Could be the conditions, but the DX is not as good as last year when I did have the tornado up. IMO, this antenna is worth every penny and I wouldn't hesitate to buy another. I am no antenna expert and can only go by what I have experienced, and currently with 2 dipoles horizontal at 35-40ft, the NV4K works better than the dipoles majority of the time anymore. Didn't use to be this way. Now I rarely switch over to the dipoles for dxing. Bottom line is I am happy and to me the NV4K is one heck of an antenna that I am glad I have now.

 

[222DBFL]

I guess the only difference is the extra coax jumper and surge arrester. And I did change out a coax run that was a bit shorter then the one I am using now. It is a 60ft section of LMR400, vs about 45ft maybe. I don't remeber the length of the coax I removed and it is still in use, just on another antenna. Other than this, the installs were the same as far as location of antenna, height, and radio being used which is an Icom 746.

 

[Needle Bender]

Hey, I have a 746, Nice rig! When the AM AMC is opened up all the way it gets surprising loud.
Best desk mic I've found for it is the Icom SM-8 - which can control 2 different rigs and has a tone adj underneath.
I see you're in FL. We should be able to DX rather easily when conditions permit. I look forward to it. L38?