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Re: High Gain and Wide Bandwidth Dipole Antenna.
Yes, EZNEC is an antenna design / evaluation application.? Even a 2-wire folded dipole has a nominal feed impedance of 300-ohms and is inappropriate to feed it with 50-ohm coax.? Dave - W?LEV On Fri, Dec 6, 2024 at 4:24?PM Chris Pannell via <chrispannell=[email protected]> wrote:
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Dave - W?LEV |
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Re: High Gain and Wide Bandwidth Dipole Antenna.
¿ªÔÆÌåÓýClaudio,
Many thanks for the reply.? Please
excuse my manners, I should have apologized for not speaking
Spanish before launching into? English!! I speak a little Greek,
but no Spanish, unfortunately. Still, it is nothing that Google
Translate can't fix.?? In answer to your question, I am in
England, down in the South East, in Kent, 70 miles from London.? I
did live for 16 years in America though, I have been back in
England for 6 years. As I was in Florida, I feel cold all the time
here.? I'll put a few more details about myself on my profile when
I get round to it, but I am primarily an optical scientist (semi-
retired) , with some background in electronics, including RF.
I see Dave-W0LEV replied saying he
thought the impedance presented at the feed was? 1.2 k Ohms, not
50 Ohms,? according to his EZNEC analysis. I have never used this,
I assume it's an RF antenna design package.? Any comments on this?
Regards,
Chris Pannell
On 06/12/2024 02:26, W0LEV via
groups.io wrote:
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Re: IoB 12/05/2024 Easley, South Carolina
Interesting. Thanks. John
On Friday, December 6, 2024 at 02:10:33 AM UTC, Dave Typinski <davetyp@...> wrote:
Really nice N event trains of S-bursts, John! -- Dave On 12/5/24 19:20, AOL via groups.io wrote:
> Good evening: >? ? ? ? ? IoB from early this morning. N events included, making the paper that > Tom sent very timely. Thanks. > >? ? ? John > |
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Re: High Gain and Wide Bandwidth Dipole Antenna.
But my EZNEC model shows 1.2 k¦¸ at the feed.? That would require a 24:1 broadband transformer plus balun.? I don't believe it is useful with 50-ohm coax at all! I sent out the EZNEC analysis earlier this afternoon.? You should translate and read it!! Dave - W?LEV On Fri, Dec 6, 2024 at 12:56?AM Claudio Alberto P¨¦rez Celeiro via <ecosanacion.interdimensional=[email protected]> wrote:
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Dave - W?LEV |
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Re: IoB 12/05/2024 Easley, South Carolina
Really nice N event trains of S-bursts, John!
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-- Dave On 12/5/24 19:20, AOL via groups.io wrote:
Good evening: |
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non IoA 12/05/2024 Easley, South Carolina
Good evening: ? ? ? ? ? non IoA from early this morning. ? ? ?John?
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Re: High Gain and Wide Bandwidth Dipole Antenna.
Claudio Alberto P¨¦rez Celeiro
Buenos d¨ªas Chris. Me alegro de tu correo. Estamos hablando de una antena para la? recepci¨®n de Onda Corta fundamentalmente. Tambi¨¦n se puede utilizar para transmisi¨®n, si uno es radioaficionado utilizando el acoplador ¨® un Choque de Radio Frecuencia, o bien, un Balun de 1:4 o 1:1 seg¨²n donde est¨¦ colocada la antena por el efecto capacitivo con casas, muros, postes de luz, etc. Volviendo a su efectividad para recibir las se?ales de J¨²piter, decir que por su Ancho de Banda, es una antena que no es cr¨ªtica en su construcci¨®n, pu¨¦s simplemente son dos brazos con tres hilos que se juntan en sus extremos, tanto en el centro y la bajada del Coaxial, como en los laterales y sus ¨¢ngulos de 45 grados. Estos tampoco son cr¨ªticos, siempre que se cumpla con la medida final de cada brazo.? Si la instalaci¨®n es horizontal, es conveniente el colocarla a un 60 % de su Longitud de Onda, es decir, unos 4,40 mtrs de altura como m¨ªnimo, ¨® a 8,80 como maximo.? Es importante decir, que NO ES importante que los brazos est¨¦n totalmente horizontales con respecto al suelo. No afecta a la recepci¨®n de la misma de una forma significativa. En cuanto a como colocarla en el terreno, es simplemente como bien dices, ponerla de Este a Oeste, as¨ª siempre tendr¨¢s una magn¨ªfica posici¨®n,? para muchas experiencias con? J¨²piter y otras experiencias en Radioastronom?a etc.? Cualquier duda que tengas, estoy a tu disposici¨®n. Pregunta: Desde donde me escribes? Gracias y un sincero saludo. Claudio? Madrid |
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IoB 12/05/2024 Easley, South Carolina
Good evening: ? ? ? ? IoB from early this morning. N events included, making the paper that Tom sent very timely. Thanks. ? ? ?John
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Re: High Gain and Wide Bandwidth Dipole Antenna.
I modeled your proposed antenna from the sketch using the latest and free version of EZNEC.?? The parameters I used are as follows: Conductivity:? 0.005 S/m Relative Dielectric Constant:? 10? (well wateres grass lawn) Height:? 15-feet? (4.6-m) You might thing twice about this configuration. The feed impedance modeled as follows.? This is for a 1200-ohm resistance!!!!!? It's a LONG WAYS from 50-ohms and standard coax!!!!! For a 2:1 SWR (at 1200-ohm feed impedance) ???????? 16.4 through 22.9 MHz For a 3:1 SWR (at 1200-ohm feed impedance)????????? 15.4 through 25.0 MHz Again, the 2:1 and 3:1 SWR are with a resistive load of 1.2 k¦¸ !!!!!? NOT 50 OHMS!!!! The following plot is with a 1200-ohm load. Here you are with a standard 50-ohm load - nearly infinite SWR!! Feeding this directly with even a 1:1 balun will introduce a whole lot of loss!!!? Not appropriate for a Jupiter Antenna. Dave - W?LEV On Sun, Dec 1, 2024 at 4:28?PM Claudio Alberto P¨¦rez Celeiro via <ecosanacion.interdimensional=[email protected]> wrote:
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Dave - W?LEV |
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Re: High Gain and Wide Bandwidth Dipole Antenna.
Claudio - a few questions:? Is the orientation of the array critical with respect to Jupiter, i.e. should the 3 wires be at 90 degrees to Jupiter? Or just align it east-west with the 3 wires at the same height from the ground? Also, is the overall height important?? Finally, do the tapered ends actually come in at 45 degrees as shown?
It looks a very interesting design.
Regards,
Chris Pannell |
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Re: Dec 02 2024. Io-C N emissions - Heliotown
Hi Sabine,
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I think in Tom's message it's just a non-standard abbreviation for "polarization" -- as in "left-hand circular polarization" -- also seen as "LCP" in the standard abbreviation. -- Dave On 12/5/24 03:10, Sabine Cremer wrote:
Great record, the N-event immediately catches the eye. Can you give a |
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Re: Dec 02 2024. Io-C N emissions - Heliotown
Great record, the N-event immediately catches the eye. Can you give a Hi Sabine, I am not able to explain "polar" in this context. Too complex for me unfortunately. Maybe others can help. In the meantime I googled and found this good paper on N-Events by Jim Brown, Dave Typinski and Richard Flagg. Hope this helps a little. - Tom |
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Re: Nancay trip report
I really enjoyed browsing through your documentation. I spent some time searching the internet to see if the strange 4 m antennas in front of the common backplane belong to the early Telefunken "Lichtenstein" RADAR and like the "W¨¹rzburg-Riese" parabolic mirror antennas were part of Nancay's legacy from a very dark time. But I found no evidence of this. I wonder what was observed in Nancay in the 4 m band?
?
Sabine
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Germany Standard time: UTC +1 hour |
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