#1	05/12-10 11:08
OZ3AFU Indlæg: 728	Hejsa Er der nogen der har nogen erfaring med Diamonds VX1000 Tribander antenne.eller evt en anden Tribander Jeg har læst en engelsks artikel hvor en skrev at SWR forhold næsten ikke var til at styre på 2meter??? VH Ronny Besvar

#2	05/12-10 11:32
Kenn Andersen Indlæg: 112	Svar til #1: hej jeg har sådan en antenne 2meter 70vm 6meter jeg har kun problem med 6 meter lidt for meget swr ellers de andre bånd fint ---------- ka Besvar

#3	05/12-10 11:46
poul nielsen Indlæg: 252	Svar til #1: EA4EOZ an amateur radio electronic enthusiast Modifications to the Diamond V2000 and similar antennas This kind of antenna has grown in popularity over the last years because it gives you a decent performance and triband capabilities. But its 50 MHz design is far from optimal. Here you can learn how to improve its 50 MHz performance in a very easy way. The physics behind the V2000 is very simple. A 5/8 antenna on 144 MHz is almost a slightly loaded quarter wave on 50 MHz. So it is not very difficult to modify the matching network to use the lower 5/8 144 MHz element as a 1/4 wave element for 50 MHz. It's very easy to do. But a quarter wave vertical antenna antenna needs an earth plane to work properly. The V2000 antenna uses a quarter wave radial as a counterpoise for 50 MHz. This is the way its uses to get it working at the three band simultaneously. There are many antennas working with this principle on the market. Some of them are: Moonraker SQBM-1000, Watson W2000, Comet CX-725 or GP-15 and Diamond V2000. This modification have been performed on a generic V2000, but surely it can be done on all the others as well. The V2000 and similar antennas have a tuned radial for 50 MHz. Because only the first 144MHz 5/8 element works at 50 MHz, the antenna is not more than a rotated V dipole in this band, a rotated dipole in a way one of its arms is vertical. The antenna was mounted about five years ago, and it has work always nicely on 2m and 70cm. On 6m I had TV (yes, I still have TV in VHF channel 2 here) noise, sometimes as high as 9+. But it has not been a problem to hear nice signals on the band, of course Es, and some nice TEP and F2. The antenna worked nicely... except if you test it with an antenna analyzer. The antenna had a very erratic SWR curve at 50 MHz, with many nulls between 48 and 56 MHz. The rig's SWR meter shown the same erratic curve. There was no dude the antenna had a problem. My first try was to adjust the radial length, but the radial was fixed, no tunning possible at all. I tried to tune the antenna cutting physically the radial, but nothing except another erratic SWR curve was obtained. I restored the radial. Here I can't transmit on 50 MHz, so SWR was not a problem at all. Some time later, playing with MMANA software, I modeled the antenna and I realized what was happening at the antenna. A quarter wave antenna really NEEDS a ground plane to work. Manufacturer do not provided a ground/earth plane for the antenna, only a tuned radial, or counterpoise as it is called some times. The problem is that a vertical quarter wave antenna with only a radial/counterpoise, isn't a vertical antenna. It's a DIPOLE. But it is a problematic dipole: The dipole does not have balun, so the coax cable and the mounting mast are the 3rd and 4th dipole arm! This will explain perfectly why the antenna has that erratic SWR curve. Googling a bit, I found a message from JA7UDA stating the antenna is really directive, with the main lobe just at the 50MHz radial direction. This was the confirmation for me that the antenna was really a no-balun V dipole on 50 MHz. V2000 simulation on MMANA. As you can see, the antenna's lobe is deformed at the 6m radial direction. This is the directivity noted by JA7UDE. This situation can produce many effects, but for me the principals are: 1.- The antenna works randomly, It depends on the installation place, mounting hardware, coaxial cable, etc, etc... 2.- The polarization of the antenna is also random: Vertical at the radial direction, a mixture of vertical-horizontal at the others... 3.- A dipole without a balun makes the coaxial cable (and mounting hardware in this case) to radiate. This is a real problem! As a experiment, I replaced all the antenna radials with full size quarter wavelength 50 MHz radials with the hope to convert it to a real ground plane antenna. The radials were made with aluminum tube, a screw and a nut. The total length was 145 cm. More details at the next image: The new radials in detail. This is only one of the multiples choices we have to make them. You can also tweak the antenna tunning adjusting their length. Make sure all three radials have the same length. Results were much better than I could never expect. The SWR curve is now the one you can expect from a 50 MHz groundplane antenna: 1.00 at 51.080 and 1.4 at 50.000 and 52.000. But for me, the main advantage is the antenna now receives exclusively vertical polarization. This is a great advantage when you are located only 40 Km away from a 250 KW TV channel 2 transmitter!!! The previous TV noise of 9+ is now reduced to S1-S2, and now some real weak signal can be heard, like meteor reflections and multi-skip Es. No changes were noticed in operation and performance on 2m and 70cm. Just as before the modification. The modified V2000. If you have this antenna, and you are not happy with its performance, try to put a real ground plane as I described here. Its cost is under 15 euros and it works much (and much is much) better than the counterpoise. Miguel A. Vallejo, EA4EOZ Back to the index page håber at du får noget ud af dette.jeg har lavet min antenne om,og det er som at få en anden antenne og 6 meter er bare super hilsen poul nielsen OZ4HT Besvar

05/12-10 11:46

poul nielsen

Indlæg: 252

Svar til #1:
EA4EOZ
an amateur radio electronic enthusiast

Modifications to the Diamond V2000
and similar antennas
This kind of antenna has grown in popularity over the last years because it gives you a decent performance and triband capabilities. But its 50 MHz design is far from optimal. Here you can learn how to improve its 50 MHz performance in a very easy way.

The physics behind the V2000 is very simple. A 5/8 antenna on 144 MHz is almost a slightly loaded quarter wave on 50 MHz. So it is not very difficult to modify the matching network to use the lower 5/8 144 MHz element as a 1/4 wave element for 50 MHz. It's very easy to do. But a quarter wave vertical antenna antenna needs an earth plane to work properly. The V2000 antenna uses a quarter wave radial as a counterpoise for 50 MHz. This is the way its uses to get it working at the three band simultaneously.

There are many antennas working with this principle on the market. Some of them are: Moonraker SQBM-1000, Watson W2000, Comet CX-725 or GP-15 and Diamond V2000. This modification have been performed on a generic V2000, but surely it can be done on all the others as well.

The V2000 and similar antennas have a tuned radial for 50 MHz. Because only the first 144MHz 5/8 element works at 50 MHz, the antenna is not more than a rotated V dipole in this band, a rotated dipole in a way one of its arms is vertical.

The antenna was mounted about five years ago, and it has work always nicely on 2m and 70cm. On 6m I had TV (yes, I still have TV in VHF channel 2 here) noise, sometimes as high as 9+. But it has not been a problem to hear nice signals on the band, of course Es, and some nice TEP and F2. The antenna worked nicely... except if you test it with an antenna analyzer. The antenna had a very erratic SWR curve at 50 MHz, with many nulls between 48 and 56 MHz. The rig's SWR meter shown the same erratic curve. There was no dude the antenna had a problem.

My first try was to adjust the radial length, but the radial was fixed, no tunning possible at all. I tried to tune the antenna cutting physically the radial, but nothing except another erratic SWR curve was obtained. I restored the radial. Here I can't transmit on 50 MHz, so SWR was not a problem at all.

Some time later, playing with MMANA software, I modeled the antenna and I realized what was happening at the antenna. A quarter wave antenna really NEEDS a ground plane to work. Manufacturer do not provided a ground/earth plane for the antenna, only a tuned radial, or counterpoise as it is called some times. The problem is that a vertical quarter wave antenna with only a radial/counterpoise, isn't a vertical antenna. It's a DIPOLE. But it is a problematic dipole:

The dipole does not have balun, so the coax cable and the mounting mast are the 3rd and 4th dipole arm! This will explain perfectly why the antenna has that erratic SWR curve. Googling a bit, I found a message from JA7UDA stating the antenna is really directive, with the main lobe just at the 50MHz radial direction. This was the confirmation for me that the antenna was really a no-balun V dipole on 50 MHz.

V2000 simulation on MMANA. As you can see, the antenna's lobe is deformed at the 6m radial direction. This is the directivity noted by JA7UDE.

This situation can produce many effects, but for me the principals are:

1.- The antenna works randomly, It depends on the installation place, mounting hardware, coaxial cable, etc, etc...

2.- The polarization of the antenna is also random: Vertical at the radial direction, a mixture of vertical-horizontal at the others...

3.- A dipole without a balun makes the coaxial cable (and mounting hardware in this case) to radiate. This is a real problem!

As a experiment, I replaced all the antenna radials with full size quarter wavelength 50 MHz radials with the hope to convert it to a real ground plane antenna. The radials were made with aluminum tube, a screw and a nut. The total length was 145 cm. More details at the next image:

The new radials in detail. This is only one of the multiples choices we have to make them. You can also tweak the antenna tunning adjusting their length. Make sure all three radials have the same length.

Results were much better than I could never expect. The SWR curve is now the one you can expect from a 50 MHz groundplane antenna: 1.00 at 51.080 and 1.4 at 50.000 and 52.000. But for me, the main advantage is the antenna now receives exclusively vertical polarization. This is a great advantage when you are located only 40 Km away from a 250 KW TV channel 2 transmitter!!! The previous TV noise of 9+ is now reduced to S1-S2, and now some real weak signal can be heard, like meteor reflections and multi-skip Es.

No changes were noticed in operation and performance on 2m and 70cm. Just as before the modification.

The modified V2000.

If you have this antenna, and you are not happy with its performance, try to put a real ground plane as I described here. Its cost is under 15 euros and it works much (and much is much) better than the counterpoise.

Miguel A. Vallejo, EA4EOZ

Back to the index page
håber at du får noget ud af dette.jeg har lavet min antenne om,og det er som at få en anden antenne og 6 meter er bare super
hilsen poul nielsen
OZ4HT

Besvar

#4	05/12-10 11:52
poul nielsen Indlæg: 252	Svar til #1: du kan også prøve EA4EOZ hjemmeside og kig under v2000 så er der mere der hilsen poul nielsen OZ4HT Besvar

#5	05/12-10 16:51
OZ3AFU Indlæg: 728	Svar til #2: SVAR til 2-3 Jeg siger mange tak for info,det er altså nogle problemer med 6meter kan jeg fornemme. VH OZ3AFU Ronny Besvar

#6	06/12-10 20:36
OZ1KS Kenneth.S Indlæg: 654	Svar til #5: Jeg kender en del der bruger den Antenne her i Aalborg.. og de Kalder den en "Luft Kølet Dummy-Load" Jeg var igang med at Lave en Test af sådan en Antenne op imod en DISCONE over fra Frank en CTE Replika.. Men vi måtte simpelt hen Droppe Testen da Diskonen ikke Duede ,,, Jeg har en Ide om at En Discone til 500Kr CTE/SIRO/DIAMOND der Dækker Amatørbåndende er mindst Ligeså god om ikke bedere end den "luft Kølede Dummiload" dem der har en rotor på har så oplevet at den er "retnings bestemt" ud over Radialen.. (antennen i toppen af røret ingen skygger) så det er faktisk en "retnings bestemt rundstråle" Hvilket jo faktisk Holder ganske godt vand hvis du kigger på et tværsnit af antennen og den måde de har Konstrueret den på.. Så spørger du mig Så er en Discone .. (ikke den JinBo/CTE KOPI fra Valby den dur ikke) Men en Discone fra CTE/SIRO/DIAMOND der går fra 50MHz og op.. vil være væsentlig bedere en V2000 på 6M og også op AF på båndet .. dem jeg selv har Køre Fortrinligt.. og der er jo forskel på 500Kr og 1200Kr.. og Bliver man taget i hånden Så at sige.. så kan jeg sagtens nøjes med at spilde 500Kr og ikke 1200Kr.. På en "Dum i loget" Antenne Hygge OZ1KS ---------- Det gør ikke noget det Koster Lidt når det DUR Vy De OZ1KS 7 3 MAN! Kan ikke Diskutere med Folk der her Ret ! Jeg skriver med stort for at Understrege Ikke Råbe Og efter som det er MIG der har skrevet det bestemmer jeg OSSE! hvad det betyder Besvar

06/12-10 20:36

OZ1KS Kenneth.S

Indlæg: 654

Svar til #5:

Jeg kender en del der bruger den Antenne her i Aalborg.. og de Kalder den
en "Luft Kølet Dummy-Load" Jeg var igang med at Lave en Test af sådan en Antenne op imod en DISCONE over fra Frank en CTE Replika.. Men vi måtte simpelt hen Droppe Testen da Diskonen ikke Duede ,,,
Jeg har en Ide om at En Discone til 500Kr CTE/SIRO/DIAMOND der Dækker Amatørbåndende er mindst Ligeså god om ikke bedere end den "luft Kølede Dummiload"
dem der har en rotor på har så oplevet at den er "retnings bestemt" ud over Radialen.. (antennen i toppen af røret ingen skygger)
så det er faktisk en "retnings bestemt rundstråle" Hvilket jo faktisk Holder ganske godt vand hvis du kigger på et tværsnit af antennen og den måde de har Konstrueret den på..

Så spørger du mig Så er en Discone .. (ikke den JinBo/CTE KOPI fra Valby den dur ikke) Men en Discone fra CTE/SIRO/DIAMOND der går fra 50MHz og op.. vil være væsentlig bedere en V2000 på 6M

og også op AF på båndet .. dem jeg selv har Køre Fortrinligt..
og der er jo forskel på 500Kr og 1200Kr.. og Bliver man taget i hånden Så at sige.. så kan jeg sagtens nøjes med at spilde 500Kr og ikke 1200Kr.. På en "Dum i loget" Antenne

Hygge OZ1KS

----------
Det gør ikke noget det
Koster Lidt når det DUR
Vy De OZ1KS 7 3

MAN!
Kan ikke Diskutere med
Folk der her Ret !

Jeg skriver med stort for at Understrege Ikke Råbe
Og efter som det er MIG der
har skrevet det
bestemmer jeg OSSE!
hvad det betyder

Besvar

#7	06/12-10 20:53
OZ1KS Kenneth.S Indlæg: 654	Svar til #5: http://www.radcom.es/pdf/diamond/vx-1000.pdf Jamen en bunke skrammel.. minus db på 50Mhz 0 DBd på 2Meter og 3DBd på UHF Så skal man da Ville det.. Her er en Discone Lige så God/Dårlig!!! men måske Knap så Klædelig.. Det er sværet at rose Ingen Ting.. Byg 1 Dipol til 50MHz .. du vil se at den har fint SWR på 2M og 70 CM en dipol vil have 2.15DBi altså NUL 0DBd på 50MHz og det er DBd der DUR.. DBi er S A L G S DBer.. og har den RESONANS Fler steder så stiger Gainet jo med Længden.. Vy De OZ1KS ---------- Det gør ikke noget det Koster Lidt når det DUR Vy De OZ1KS 7 3 MAN! Kan ikke Diskutere med Folk der her Ret ! Jeg skriver med stort for at Understrege Ikke Råbe Og efter som det er MIG der har skrevet det bestemmer jeg OSSE! hvad det betyder Besvar

06/12-10 20:53

OZ1KS Kenneth.S

Indlæg: 654

Svar til #5:
http://www.radcom.es/pdf/diamond/vx-1000.pdf

Jamen en bunke skrammel.. minus db på 50Mhz
0 DBd på 2Meter og 3DBd på UHF
Så skal man da Ville det..
Her er en Discone Lige så God/Dårlig!!! men måske Knap så Klædelig..

Det er sværet at rose Ingen Ting..
Byg 1 Dipol til 50MHz .. du vil se at den har fint SWR på 2M og 70 CM
en dipol vil have 2.15DBi altså NUL 0DBd på 50MHz og det er DBd der DUR.. DBi er S A L G S DBer.. og har den RESONANS Fler steder så stiger Gainet jo med Længden..

Vy De OZ1KS

Besvar

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