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CX2SA > SATDIG 04.09.08 03:34l 211 Lines 7282 Bytes #999 (0) @ WW
BID : 30788_CX2SA
Read: GUEST
Subj: AMSAT-BB-digest V3 446
Path: IZ3LSV<IK2XDE<F5GOV<CX2SA
Sent: 080904/0122Z @:CX2SA.LAV.URY.SA #:30788 [Minas] FBB7.00e $:30788_CX2SA
From: CX2SA@CX2SA.LAV.URY.SA
To : SATDIG@WW
Today's Topics:
1. Re: Information request (WILLIAMS MICHAEL)
2. Re: sun noise and other natural noise sources (i8cvs)
3. presentation and AO-51 demonstration, tomorrow (Thursday, 4
September) (Patrick STODDARD (WD9EWK/VA7EWK))
----------------------------------------------------------------------
Message: 1
Date: Wed, 3 Sep 2008 08:00:46 -0700 (PDT)
From: WILLIAMS MICHAEL <k9qho6762(AT)sbcglobal.net>
Subject: [amsat-bb] Re: Information request
To: amsat-bb(AT)amsat.org
Message-ID: <994390.26258.qm(AT)web82705.mail.mud.yahoo.com>
Content-Type: text/plain; charset=iso-8859-1
The article is in the September/October?2000 issue.
?
I built the project, but it was not a complete success somewhat of a
disappointment.
?
I am modifying the?circuit, etching a new PCB, and going to try it from a
different design approach.
?
The mini-circuits VCO, and power divider cost $50.00 for these two devices.
They can be ordered online with a?credit card.
?
If I can help you with anything, please email.
?
Mike
K9QHO
AMSAT 33589
?
?
?
?
------------------------------
Message: 2
Date: Wed, 3 Sep 2008 20:03:04 +0200
From: "i8cvs" <domenico.i8cvs(AT)tin.it>
Subject: [amsat-bb] Re: sun noise and other natural noise sources
To: "Michael Heim" <kd0ar(AT)sbcglobal.net>, "AMSAT-BB"
<amsat-bb(AT)amsat.org>
Message-ID: <001001c90def$515f1360$0201a8c0(AT)tin.it>
Content-Type: text/plain; charset="iso-8859-1"
----- Original Message -----
From: "Michael Heim" <kd0ar(AT)sbcglobal.net>
To: <AMSAT-BB(AT)amsat.org>
Sent: Wednesday, September 03, 2008 2:06 AM
Subject: [amsat-bb] sun noise and other natural noise sources
> I am working on an S-band receive setup. I currently operate X band
> terrestrial, and used sun noise as a test of my receive equipment there.
> It is quite weak on 10 GHz. Noise from the earth (aimed at the ground) is
> many times stronger. Aiming at trees, buildings, etc produce substantial
> noise on 10 GHz. The question I have is... Can I use the same techniques
> on 2.4 GHz? Of course antenna gain is lower, but noise figure should
> be fairly close - 1dB or so....
>
> I have 2 units for 2.4 I'm testing. one has an integral yagi antenna,
> supposedly about 16dB gain. The other has an N connector, of which I have
> not designed an antenna for it yet.
>
> So, the question is... is sun noise stronger, weaker on 2.4 than on 10
> ghz? If equipment is functioning properly should I be able to detect the
> sun? I actually didnt think about trying to hear a tree on it, but they
> should also be noise sources on that band as well.
>
> Michael Heim
> ARS KD0AR
Hi Michael, KD0AR
The Sun radiates uncoherent energy into the radio spectrum in form of
withe noise and the power of it is measured in Solar Flux Units i.e. in
sfu
-22
One sfu is equivalent to a power of 10 watt / square meter / Hz
incident over the aperture area of your antenna and 1 sfu is 10.000 time
greater than the radio flux unit Jansky used by radioastronomers.
The energy radiated by the Sun is direcly proportional to the frequency
and infact if you look at the following pages
http://www.swpc.noaa.gov/ftpdir/indices/DSD.txt
http://www.swpc.noaa.gov/ftpdir/latest/curind.txt
you will find that at the same time 04:00 UTC of day 3 september 2008 the
value of sfu measured by the NOAA stations in Learmonth and Penticton was
66 sfu at 2800 MHz
233 sfu at 8800 MHz
522 sfu at 15400 MHz
indicating that the energy in watt for each square meter and for each Hz of
bandwidth radiated by the Sun increases increasing the frequency.
We amateurs we refere our calculations to the frequency of 2800 MHz or
10.7 cm tanks to W8MIF wich converted the sfu at 2800 MHz into all
corresponding values of sfu for the amateur bands of 1296-2304-3456-5760
and 10368 MHz as reported by an article written by Bob Atkins KA1GT
into the ARRL UHF/Microwave Experimenters Manual ARRL order Nr 3126
In addition tanks to Melvin WR0I of the North Texas Microwave Society we
have the software NOISE.EXE
Using it directly with the sfu at 2800 MHz we can easily calculate the
expected Sun Noise for 9 amateurs bands from 144 MHz to 10 GHz
Supposing that your 10 GHz dish has a diameter of 60 cm with a gain
of 33 dBi at 50% efficiency with an antenna temperature Ta= 10 kelvin
due to side lobes and spillower looking at the ground and a receiver with
an overall Noise Figure of 1 dB so that Te=75 kelvin then your System
Temperature Tsys = 75+10 = 85 kelvin
Since the Sky temperature at 10 GHz is 5 kelvin with 66 sfu at 2800 MHz
today NOISE.EXE says that you should receive a Sun Noise of about
4.4 dB at 10 GHz
Going to 2.4 GHz you says that your antenna has a gain of 16 dBi
corresponding to the gain of a dish of about 40 cm or 15.7 inch at 50%
efficiency.
The antenna temperature Ta at 2.4 GHz for a dish of that size is at best
about 70 kelvin and since the overall Noise Figure of your receiving system
is 1 dB then Te= 75 kelvin and the System Temperature Tsys=75+70=145 kelvin
The Sky temperature at 2.4 GHz is about 50 kelvin so that to day with
66 sfu at 2800 MHz NOISE.EXE says that at best your Sun Noise is only
0.3 dB
By the way in a separate message I have sent to you NOISE.EXE and several
other related papers so that you can play with it "all night"
Have fun and 73" de
i8CVS Domenico
------------------------------
Message: 3
Date: Wed, 3 Sep 2008 11:24:12 -0700 (PDT)
From: "Patrick STODDARD \(WD9EWK/VA7EWK\)" <amsat-bb(AT)wd9ewk.net>
Subject: [amsat-bb] presentation and AO-51 demonstration, tomorrow
(Thursday, 4 September)
To: amsat-bb(AT)amsat.org
Message-ID: <773336.66061.qm(AT)web56104.mail.re3.yahoo.com>
Content-Type: text/plain; charset=us-ascii
Hi!
I will visit the Yavapai Amateur Radio Club in Prescott AZ:
http://www.w7yrc.org/
tomorrow evening. I will give a satellite-related presentation
during the club's regular monthly meeting that starts at 1900 local
(Friday 0200 UTC). About 30 minutes before the meeting, there is
an AO-51 pass that covers much of North America. If the satellite
is on and the weather is good, I will be doing a demonstration as
WD9EWK from outside the club's meeting site. If you hear me on,
please feel free to give me a call and say "hello" to those who
are listening to the demonstration.
Prescott is in Yavapai County and grid DM34. It is approximately
100 miles/160km north of Phoenix, in the mountains with an elevation
of one mile (5280 feet/1609m). I was in Prescott for this club's
hamfest in late May, and have made several trips to this grid in
the past few months. Besides my trips, there has been some satellite
activity from this area.
I will send QSL cards for all contacts made during the demonstration.
There will be no need for you to send me a QSL card or SASE to
receive my card.
Thanks in advance, and 73!
Patrick WD9EWK/VA7EWK
http://www.wd9ewk.net/
------------------------------
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End of AMSAT-BB Digest, Vol 3, Issue 446
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