Jo-Gunn: Son of a Gunn

[bob85]

hey chief i modelled the sigma4 using my EZBOB software and got some interesting results for you to peruse,

its a simple program with a very user friendly interface similar to paint,

initial results look very promising and seem to match my own real world experiences,
i am sure i am getting pretty good at this antenna designing because i honestly dont really need to use the software anymore,
the results always turn out exactly how i imagined them to be,

every once in a while i will run an antenna through the program just to reassure myself i am still going in the right direction,

the program seems pretty accurate for models calculated over average soil which around here is,

( 13%moisture /27% loam/ 7% clay/53% b_llsh_t )

:twisted:

 

[Master Chief]

:lol :lol :lol :lol :lol :lol :lol :lol :lol :lol :lol :lol :lol :lol

 

[tecnicoloco]

EZBOB Modeling Program

Hello Bob85:
Where can I get a Copy of EZBOB ?:shock:


Tecnicoloco
73's :twisted: :twisted: :twisted:

 

[Robalo]

 

[KingCobra_CDX882]

:?

i thought the topic of this thread had something to do with a
Jo Gun son of a gun

:mrgreen: :gdlf :mrgreen:
:mad :nutzo :mad

 

[bob85]

it does 882,

i would like some answers pls

discounting the fact that i have had all my antennas mounted at heights ranging from ground mounted to 73feet to the feedpoint in an open field exept the i10k,
and i cannot turn back time nor can i mount the 5/8 any higher than about 35 feet at this location,

can you tell me this,

A, could a halfwave antenna both transmit and recieve further than any 5/8wave groundplane antenna when mounted anywhere from 12 feet to feedpoint to around 35 feet to feedpoint and at the same time give increased signal strength locally :?:

B, could a halfwave antenna both transmit and recieve further than any 5/8wave groundplane antenna mounted at anywhere from 12 feet to feedpoint and 35 feet to feedpoint when mounted with the antenna tips at roughly the same height,
the 1/2wave been the avanti antenna or its extended derivatives 27 to 32 feet long :?:

C, could the jogunn son of a gunn radials be mounted with an upwards flair just for experimental purposes :?:

D, could the jogunn radials be mounted with an upwards flair that will give an angle of say 25 to 30 degrees from the vertical radiator just for experimental purposes :?:

E, what happens to feedpoint impedance if you extend the avanti radiator to around 31feet :?:

f, what happens if you move gamma shorting strap down towards the base of antenna and retune gamma with said extended radiator for a good vswr whilst monitoring a station say 70+ miles out on a steady fm signal and optimising signal strength:?:

G, would you be willing to test the jogunn in such a way :?:

h, in your opinion if i fixed up my 31ft hybrid would i be able again to talk to my friends on the coast whom i have not talked to since i took the antenna down while other locals on hills such as charlie oscar can still talk to them:?:

I, why in your opinion could i barely hear my buddy on the coast when he took his 31footer down for the winter and erected his 5/8 groundplane and virtually not at all when he erected his imax2000, :?:

J,why when he put it back up because he could barely hear me could we talk every evening once again, :?:

K, why when the winter winds broke the top 3 sections off his 31 footer and he used the atu in his 950sdx could i still talk to him noticeably better than i could on his IMAX2000 :?:

remember its only a halfwave, a halfwave minus 3 sections is not much of an antenna at all,

L, in your opinion why did the 5/8wave seem to outperform the avanti hybrids when talking short hop skip into this side of europe when mounted at anywhere from 12 feet to 35 feet to the feedpoint but not work japan.india.australia on 10mtrs when my local stock and extended avanti users could still talk to those stations at that time :?:

remember the hybrid came down the 5/8 went up at same height same day same sporadic conditions,

WHY DO WE SEEM TO LOVE THE BANTER

 

[Marconi]

it does 882,

i would like some answers pls

discounting the fact that i have had all my antennas mounted at heights ranging from ground mounted to 73feet to the feedpoint in an open field exept the i10k,
and i cannot turn back time nor can i mount the 5/8 any higher than about 35 feet at this location,

sounds like a lot of time has pasted in testing and maybe even a station move was made as well. I too would discount these discounting factors.

can you tell me this,

A, could a halfwave antenna both transmit and recieve further than any 5/8wave groundplane antenna when mounted anywhere from 12 feet to feedpoint to around 35 feet to feedpoint and at the same time give increased signal strength locally

I have seen this happen when comparing two verticals at the same time using a switch box. When I was switching between my antennas to several local stations I got mixed results and I was surprised. The first such test was when comparing my I-10K to a Wolf Radio .50-11m ½ wave vertical with no ground plane and that is when I began to test such differences. As expected, the I-10K produced the best signal most of the time, but there were definitely exceptions in my results.

B, could a halfwave antenna both transmit and recieve further than any 5/8wave groundplane antenna mounted at anywhere from 12 feet to feedpoint and 35 feet to feedpoint when mounted with the antenna tips at roughly the same height,
the 1/2wave been the avanti antenna or its extended derivatives 27 to 32 feet long

I get the gist of your comment regarding tip height, but do not get a clear picture of the rest of your comments here. I have noticed that when I set the tip heights of antennas the same, the responses tend to become more similar among dissimilar antennas. Are you suggesting that the Sigma IV is a ½ wave antenna like an 18 footer is?

C, could the jogunn son of a gunn radials be mounted with an upwards flair just for experimental purposes

D, could the jogunn radials be mounted with an upwards flair that will give an angle of say 25 to 30 degrees from the vertical radiator just for experimental purposes

are you wondering if the son of a gunn would then act like a Sigma IV?

E, what happens to feedpoint impedance if you extend the avanti radiator to around 31feet

it would change a bit from that at the original frequency, but likely come back towards a tune as you went down in frequency to resonance. The sweet spot on the radiator may also change a bit.

f, what happens if you move gamma shorting strap down towards the base of antenna and retune gamma with said extended radiator for a good vswr whilst monitoring a station say 70+ miles out on a steady fm signal and optimising signal strength:?:

I don’t see the point as you do and I do not see a gamma working as you are suggesting either.

G, would you be willing to test the jogunn in such a way

h, in your opinion if i fixed up my 31ft hybrid would i be able again to talk to my friends on the coast whom i have not talked to since i took the antenna down while other locals on hills such as charlie oscar can still talk to them:?:

I, why in your opinion could i barely hear my buddy on the coast when he took his 31footer down for the winter and erected his 5/8 groundplane and virtually not at all when he erected his imax2000,

it could be that the 31 footer produces a bit better response in a power lobe generated, that favors the location of your coastal buddies. It could also be that the Sigma IV instead produces a lower and more favorable angle of radiation than the 5/8wave antenna. This would be contrary to popular opinion about these extended antennas. I believe this is basically a unique design advantage for the Sigma and also accounts for its seeming better long distance response as well.

J,why when he put it back up because he could barely hear me could we talk every evening once again,

K, why when the winter winds broke the top 3 sections off his 31 footer and he used the atu in his 950sdx could i still talk to him noticeably better than i could on his IMAX2000

it is my opinion that there probably was enough of the radiator remaining to produce the maximum current in the current distribution along the element. The tip of the element is mostly important for resonance only. This condition may have little effect on performance since there is very little radiating current in this area. Of course the matching load would change, but unless it adversely affected the transmitter, that too would be of little consequence.

remember its only a halfwave, a halfwave minus 3 sections is not much of an antenna at all,

L, in your opinion why did the 5/8wave seem to outperform the avanti hybrids when talking short hop skip into this side of europe when mounted at anywhere from 12 feet to 35 feet to the feedpoint but not work japan.india.australia on 10mtrs when my local stock and extended avanti users could still talk to those stations at that time

I believe 5/8 wave elements tend to produce very good power at an angle of 20 – 40 degrees while also showing a bit less power at 12 degrees and less. Responses here depend to a large degree on soil conditions between stations. Clutter on the horizon is always a factor as well. Again, the design of the Sigma may well be the factor that produces the results you see in both the coastal contacts and DX. Concerning the comparison to the Imax. It is my opinion that the Imax has high gain, but when the conditions are very quite and you are reaching out towards the effective end of your range that noise becomes a real factor with these antennas. This makes it less likely you will be able to hear as well. This most likely has to do with common mode current affects with the Imax not decoupling the feed line well at the feed point.

remember the hybrid came down the 5/8 went up at same height same day same sporadic conditions

 

[bob85]

hello marconi,
thanks for taking time to give your view,

the gamma shorting strap was indeed brought down the radiator when compared to the stock vector 4000 antenna, i do not pretend to know the why's or hows but it works for us over here,
no i am in no way suggesting its a halfwave antenna at all, neither would i stake my life on it that it is not,
i do not think it is a halfwave with a modified pettern but i cannot see rf as i wish i could,

when comparing 2 antennas spaced at a wavelength or more in our field and one wavelength to feepoints they interect with each other and one set of readings changes when the two antennas are swapped round on the poles,

am i wondering if the jogunn with upswept radials could act like a sigma4?
yes it states so in the avanti patent that if the angle between the legs and the basket is incrased to around 30 degrees where the radial dimentions would be around 7feet and in some cases even more than 30 degrees then an even larger increase in gain can be had over the 5/8 than is seen with the stock avanti leg angle,
it does not however say if that increase in gain is at a favourable angle,

the short hop thing,

at this time i think the avanti does not seem to suffer from coupling effects like a conventional antenna as they work very well even when the mounting stub is actually stuck in the ground compared to other antennas mounted at such a low height,

my old 5/8 antennas only worked very well when i had them at close to or at 2 full wavelengths to feedpoint,
unfortunately i cannot test the i10k at this height in this location,

the only direct a/b comparisons i have against the 10k is my imax2000 and my friends 5/8 sirio 827, the i10k soundly beats them both

it would be unfair to compare the dx results between my avanti hybrid and the 10k because dx conditions change all the time and to be fair we are in a trough with only sporadic short hop skip into europe from my location at this time, though i did work iceleand on the i10k when my locals could not make the trip,

can i talk to stations/friends on the coast every day as i could with the hybrid? no and neither could one of them when he took his 31 footer down and erected a groundplane then an imax2000,
could we talk every day as soon as he put the 31ft antenna back up?,yes

i have had it explained to me that when we extend the radiator to around 31foot then it is no longer a resonant antenna,

i do not dispute this at all as the guy telling me surely understands antennas better than i do,
does it still work better for us than the 3/4wave radiator?,
yes without a doubt though i do not understand why,

do i realise that ground conditions and everything in the nearfield effects my antennas pattern, of course it does,
does the avanti seem to be bothered as much as other antennas by things around it, NOPE,

am i the only person over here to test the style of antenna against others with both 3/4 and extended radiators?, no

what antenna do the guys that have tested the antenna now use??
they use an extended avanti sigma4...

the people who claim you must put up a beam to see any real gains over any other vertical antenna, DONT BE SO STUPID! YOU HAVE NEVER HAD OR TESTED WHAT I HAVE USED FOR OVER 25 YEARS IF THATS WHAT YOU THINK..

 

[Master Chief]

A, could a halfwave antenna both transmit and recieve further than any 5/8wave groundplane antenna when mounted anywhere from 12 feet to feedpoint to around 35 feet to feedpoint and at the same time give increased signal strength locally :?:

Head to head with full size antennas; NO.

B, could a halfwave antenna both transmit and receive further than any 5/8wave groundplane antenna mounted at anywhere from 12 feet to feedpoint and 35 feet to feedpoint when mounted with the antenna tips at roughly the same height, the 1/2wave being the Avanti antenna or its extended derivatives 27 to 32 feet long :?:

Head to head with full size antennas; NO.

C, could the Jo-Gunn son of a gunn radials be mounted with an upwards flair just for experimental purposes :?:

Yes.

D, could the jogunn radials be mounted with an upwards flair that will give an angle of say 25 to 30 degrees from the vertical radiator just for experimental purposes :?:

With some slight tubing modifications, sure.

E, what happens to feedpoint impedance if you extend the avanti radiator to around 31feet :?:

It would change.

F, what happens if you move gamma shorting strap down towards the base of antenna and retune gamma with said extended radiator for a good vswr whilst monitoring a station say 70+ miles out on a steady fm signal and optimizing signal strength:?:

I don't know.

G, would you be willing to test the jogunn in such a way :?:

Sure!

H, in your opinion if i fixed up my 31ft hybrid would i be able again to talk to my friends on the coast whom i have not talked to since i took the antenna down while other locals on hills such as charlie oscar can still talk to them:?:

All things being equal, if it worked before, it should work again.

I, why in your opinion could i barely hear my buddy on the coast when he took his 31 footer down for the winter and erected his 5/8 groundplane and virtually not at all when he erected his imax2000, :?:

Not knowing what may or may not have changed, I'd say the original antenna had a favorable antenna pattern.

J,why when he put it back up because he could barely hear me could we talk every evening once again, :?:

See above.

K, why when the winter winds broke the top 3 sections off his 31 footer and he used the atu in his 950sdx could i still talk to him noticeably better than i could on his IMAX2000 :?:

Cause the iMAX 2000 sucks?

remember its only a halfwave, a halfwave minus 3 sections is not much of an antenna at all,

We discussed the 31' version was possibly a 5/8 over a 1/4 and not a 1/2 wave......effectively.

L, in your opinion why did the 5/8 wave seem to outperform the Avanti hybrids when talking short hop skip into this side of europe when mounted at anywhere from 12 feet to 35 feet to the feedpoint but not work japan, india, australia on 10mtrs when my local stock and extended avanti users could still talk to those stations at that time :?:

The antenna's patter and major lobe.

remember the hybrid came down the 5/8 went up at same height same day same sporadic conditions,

This doesn't change my last answer! 8)

 

[Marconi]

Bob says:

when comparing 2 antennas spaced at a wavelength or more in our field and one wavelength to feepoints they interect with each other and one set of readings changes when the two antennas are swapped round on the poles,

What response did you use to determine that this was interaction between antennas when trading places?

 

[bob85]

marconi, i used signal strength only,
back then i had 2 choices,
test them both together on 36ft poles same length coax from same reel,
one wavelength was a typical mounting height for stations round me and i could easily walk a 36ft scaffold pole up and down for swapping antennas about or i could use one pole move the untested antenna well away and lay it down at 90 degrees to the tested antenna get reports take notes and swap antennas within a couple of minutes and retest,
i prefer the single antenna and swap method,

i am not even sure what did what its a long time ago, what i do remember is swapping positions changed signal readings more than just moving one antenna from one pole to the other,
it was difficult to determine was the best antenna when i tested both at once,
i may be wrong but i also seem to remember the biggest changes were with stations that were more or less inline with the antennas and less so off the sides,

was there any method in my madness??,
at that time i thought there was, i now realise my testing only applied to my dads field and at that mounting height and most likely other factors

 

[bob85]

hey chief maybe not the best time to ask but any news or pics of the jogunn or the force12 :?:

 

[Master Chief]

no.

I will soon though, I promise!

 

[bob85]

looking forwards to seeing it

 

[bob85]

i know your a busy guy chief but are you holding out on us with this antenna,
did you use my rivets to fix it back together ?

sorry you know how it is i could not resist :twisted: