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CX2SA > SATDIG 08.08.09 21:20l 286 Lines 8159 Bytes #999 (0) @ WW
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Today's Topics:
1. Re: Antenna project with 2 ELK antennas (Jean-Fran?ois M?nard)
2. AO-51 V/S mode (Allen Vinegar)
3. Re: AO-51 V/S mode (Greg D.)
----------------------------------------------------------------------
Message: 1
Date: Sat, 8 Aug 2009 12:50:44 -0400
From: Jean-Fran?ois M?nard <jf.va2ss@xxxxx.xxx>
Subject: [amsat-bb] Re: Antenna project with 2 ELK antennas
To: i8cvs <domenico.i8cvs@xxx.xx>, amsat-bb@xxxxx.xxx
Message-ID:
<b6cfdc060908080950se68a138g40594f52d97bc82d@xxxx.xxxxx.xxx>
Content-Type: text/plain; charset=ISO-8859-1
Le 8 ao?t 2009 11:54, i8cvs<domenico.i8cvs@xxx.xx> a ?crit :
> Hi Jean, VA2SS
>
> Since the ELK antenna is a log-periodic antenna covering a wide
> band from 2 meters and 70 cm it is difficult to connect 2 ELK in
> phase and gain 3 dB in 2 meters and 70 cm as well.
>
> Also it is difficult to connect 2 ELK with a phase offset of 90?
> to get circular polarization in 2 meters and 70 cm
>
> I would prefere to put one ELK horizontal and the other one
> vertical feeding each antenna with an individual coax line.
>
> Using a coax relay in the shack you can immediately switch
> from the Horizontal to the Vertical polarization.
>
> About the distance between the antennas over the plastic boom
> the distance is a function of the antenna gain and higher is the gain
> (in order do not overlap the aperture area of each antenna) larger
> must be the distance between booms
>
> Since the gain of the ELK in the lover 2 meters band is 6.6 dBd
> over the dipole or 6.6 +2.14 = 8.7 dBi over the isotropic then the
> aperture area wich is a circle perpendicular to the antenna boom
> can be computed using the following formula:
>
> ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? / ?2
> ? ? ? ? ? ? ? ? ? ? ? ? ? G x /\
> Aperture area= ----------
> ? ? ? ? ? ? ? ? ? ? ? ? ? 4 x Pi
>
> Since G= 8.7 dBi = 7.41 in power ratio
>
> ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?2
> ? ? ? ? ? ? ? ? ? ? ? ? ? ? 7.41 x 2
> Aperture area= -------------- = 2.36 square meters
> ? ? ? ? ? ? ? ? ? ? ? ? ? ? 4 x 3.14
>
> A circle with a geometrical area of 2.36 square meters
> has a radius of
>
> ? ? ? ? ? ? \ ? ? ? /--------------------
> radius = \ ? / ? ? ? 2.36 / 3.14 ? ? ? ?= 0.86 ?meters
> ? ? ? ? ? ? ? ?\/
>
> Hence the distance between the booms is 0.86 x2 = 1.72 meters
>
> In this condition both aperture areas are tangents but it is better
> to overlap the areas a 10 % to prevent the generation of side lobes
> so ?that a distance of 1.55 meters between the antenna booms
> is recommended.
>
> I hope this helps
>
> 73" de
>
> i8CVS Domenico
>
> ----- Original Message -----
> From: "Jean-Fran?ois M?nard" <jf.va2ss@xxxxx.xxx>
> To: "i8cvs" <domenico.i8cvs@xxx.xx>
> Sent: Saturday, August 08, 2009 4:00 PM
> Subject: Re: [amsat-bb] Antenna project with 2 ELK antennas
>
>
> Hi,
>
> I do not know much about antenna... But I tought that could be better
> for satellite this way... I did not do any search at this time about
> this project... it is only an idea that I had.
>
> If you have any suggestion for such project using 2 Elk antenna....
> please let me know.
>
> I don't want to spend much money at this moment... and I have only
> these 2 antenna.
>
Wow !!
Thanks !! This is the kind of answer that I really like.
I will try this with the recommendation you gave me. I'm not familiar
with all those formulas regarding antenna, so a little help time to
time is really helpful.... I like to learn, so you won't repeat the
same thing twice.
Thank again.
Best 73
J-F VA2SS
> 73
>
>
> 2009/8/8 i8cvs <domenico.i8cvs@xxx.xx>:
>> ----- Original Message -----
>> From: "Jean-Fran?ois M?nard" <jf.va2ss@xxxxx.xxx>
>> To: "AMSAT Mailing list" <amsat-bb@xxxxx.xxx>
>> Sent: Thursday, August 06, 2009 10:44 PM
>> Subject: [amsat-bb] Antenna project with 2 ELK antennas
>>
>> Hi,
>>
>> I have 2 ELK antennas here, and I would like to do an experiment with
>> these two antennas. I would like to stack side by side, one vertical,
>> and one horizontal.
>>
>> 73
>>
>> Jean-Fran?ois M?nard
>> VA2SS
>>
>> =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
>> AMSAT www.amsat.org / Member #37102
>> ARRL www.arrl.org
>> =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
>>
>> Hi Jean, VA2SS
>>
>> Staking 2 ELK antennas side by side,one vertical,and one horizontal
>> what type of polarization you plan to get ?
>>
>> 73" de
>>
>> i8CVS Domenico
>>
>>
>>
>>
>
>
>
> --
> Jean-Fran?ois M?nard
> VA2SS
>
> =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
> AMSAT www.amsat.org / Member #37102
> ARRL ?www.arrl.org
> =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
>
>
>
>
>
>
>
>
>
--
Jean-Fran?ois M?nard
VA2SS
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
AMSAT www.amsat.org / Member #37102
ARRL www.arrl.org
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
------------------------------
Message: 2
Date: Sat, 8 Aug 2009 13:48:24 -0400
From: "Allen Vinegar" <tokens@xxxxxxx.xxx>
Subject: [amsat-bb] AO-51 V/S mode
To: <amsat-bb@xxxxx.xxx>
Message-ID: <B87838EA29CC4BC88F1066DF8E1C8725@xxxxx>
Content-Type: text/plain; charset="iso-8859-1"
I would like to try this mode using a K5GNA downconverter. The problem is I am
using an FT-736R and apparently you can not have Xmit and Rcv on same band in
satellite mode. I am using SATPC-32 for doppler control. The downconverter
uses a 2m IF. Anyone else with an FT-736R have this worked out?
Many thanks!!
73,
Al W8KHP
------------------------------
Message: 3
Date: Sat, 8 Aug 2009 11:09:37 -0700
From: "Greg D." <ko6th_greg@xxxxxxx.xxx>
Subject: [amsat-bb] Re: AO-51 V/S mode
To: <tokens@xxxxxxx.xxx>, <amsat-bb@xxxxx.xxx>
Message-ID: <BLU133-W80BC8F113BFE1D1CC20D3A9080@xxx.xxx>
Content-Type: text/plain; charset="iso-8859-1"
Hi Allen,
If you have both Rx and Tx on the same band, then both directions will be
using the same RF connector on the rig. I suppose if you are REALLY careful
you can put an antenna switch between them, but you need to make really sure
you don't transmit into the back of your downconverter. And since you won't
be able to hear yourself, this arrangement is probably only going to work in
FM mode.
I've done VS with my FT-736R, but my 13cm receive is through a separate rig
(an all-mode scanner). I also modified my downconverter for a 300mhz IF so
that I wouldn't have any interference regardless of the uplink (2m/70cm). The
736 was only used for the uplink.
Good luck,
Greg KO6TH
> From: tokens@xxxxxxx.xxx
> To: amsat-bb@xxxxx.xxx
> Date: Sat, 8 Aug 2009 13:48:24 -0400
> Subject: [amsat-bb] AO-51 V/S mode
>
> I would like to try this mode using a K5GNA downconverter. The problem is I
am using an FT-736R and apparently you can not have Xmit and Rcv on same band
in satellite mode. I am using SATPC-32 for doppler control. The downconverter
uses a 2m IF. Anyone else with an FT-736R have this worked out?
>
> Many thanks!!
>
> 73,
> Al W8KHP
> _______________________________________________
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