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CX2SA > SATDIG 04.11.08 16:04l 829 Lines 27909 Bytes #999 (0) @ WW
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Sent: 081104/1357Z @:CX2SA.LAV.URY.SA #:46210 [Minas] FBB7.00e $:46210_CX2SA
From: CX2SA@CX2SA.LAV.URY.SA
To : SATDIG@WW
Today's Topics:
1. Re: Yaesu FT-847 (Nate Duehr)
2. Re: - AMSAT-BB Contents From MM3YCG (Callum Graham)
3. Re: help with wisp (Gordon JC Pearce MM3YEQ)
4. Preamp advice, pse (ANTHONY JAPHA)
5. Re: Preamp advice, pse (Jim Jerzycke)
6. Re: Preamp advice, pse (Mark Spencer)
7. Re: Yaesu FT-847 (tosca005@xxx.xxxx
8. Re: help with wisp (Alan)
9. IC-910 and 1296 Board for Sale (John Henderson N4NAB)
10. Re: Yaesu FT-847 (Luc Leblanc)
11. "off topic" Intelsat Retires the Oldest Commercial
Communications Satellite (robert@xxxxxxxxxxxxxx.xxxx
12. Re: GO-32 Status? (TOFFY)
13. GS-5500 (Dave)
14. Re: Preamp advice, pse (i8cvs)
15. Re: Preamp advice, pse (Edward Cole)
----------------------------------------------------------------------
Message: 1
Date: Mon, 03 Nov 2008 13:48:21 -0700
From: Nate Duehr <nate@xxxxxxxx.xxx>
Subject: [amsat-bb] Re: Yaesu FT-847
To: Sebastian <w4as@xxxxxxxxx.xxx>
Cc: AMSAT BB <AMSAT-BB@xxxxx.xxx>
Message-ID: <490F6395.20606@xxxxxxxx.xxx>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Sebastian wrote:
> And Nate, thanks but I'm aware of how to change the baud rate on the
> radio, the problem was with the software.
Glad you got it working... have fun! :-)
Nate WY0X
------------------------------
Message: 2
Date: Mon, 3 Nov 2008 21:59:56 +0000 (GMT)
From: Callum Graham <mm3ycg@xxxxxxxxxx.xxx>
Subject: [amsat-bb] Re: - AMSAT-BB Contents From MM3YCG
To: amsat-bb@xxxxx.xxx
Message-ID: <980827.57367.qm@xxxxxxxx.xxxx.xxx.xxxxx.xxx>
Content-Type: text/plain; charset=utf-8
Thanks to everyone who gave me info regarding working VO 52, I've not had much
time today tho I will give it a go during the week...so listen out for me HI?-
And thanks again
73 De Callum MM3YCG
------------------------------
Message: 3
Date: Mon, 03 Nov 2008 23:05:38 +0000
From: Gordon JC Pearce MM3YEQ <gordonjcp@xxxx.xxx>
Subject: [amsat-bb] Re: help with wisp
To: Jeff Wandling W7BRS <jw@xxxxx.xxx>
Cc: amsat-bb@xxxxx.xxx
Message-ID: <490F83C2.2050008@xxxx.xxx>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Jeff Wandling W7BRS wrote:
> "WiSP for Windows 95/98 or NT 4.0 is current. Written by Chris Jackson,
> ZL2TPO."
WTF? For suitable versions of "current", perhaps!
> WiSP may be obsolete? What version are you running?
I'll say.
It's one of the odd things I've noticed about software for amateur
radio, though. It all seems to be really badly written shareware for
old versions of Windows, with no source code available and quite often a
fee required to "unlock" the useful bits - which, if it hasn't been
updated in ten years, you may not be able to get any more!
I would have thought that radio amateurs would have grokked the concept
of open source, if anyone did...
Gordon
------------------------------
Message: 4
Date: Mon, 3 Nov 2008 18:45:04 -0500
From: "ANTHONY JAPHA" <tjjapha@xxxxxxxxx.xxx>
Subject: [amsat-bb] Preamp advice, pse
To: amsat-bb@xxxxx.xxx
Message-ID: <380-22008111323454578@xxxxxxxxx.xxx>
Content-Type: text/plain; charset=US-ASCII
Bird Lovers,
Pse let me have advice on which of the following ARR 2 mtr preamps I should
get: P144VDA: 1.0db nf, 15 db gain; or P144VDG: 0.5db nf, 24db gain.
The preamp will be used primarily for AO-7. I operate only portable in a high
noise environment here in Manhattan. I doubt the nf difference is at all
meaningful in my use. The large difference in gain between the 2 preamps may
not be impt. either, that is the real question. My XCVR is the FT-817.
Another 817 is used to transmit, running abt 15-20 watts into a small amp.
with an Arrow split between 2 booms on 2 tripods only abt. 1 ft. from each
other.
So what's the verdict?
Tnx and 73,
Tony, N2UN
------------------------------
Message: 5
Date: Mon, 3 Nov 2008 16:22:45 -0800 (PST)
From: Jim Jerzycke <kq6ea@xxxxxxx.xxx>
Subject: [amsat-bb] Re: Preamp advice, pse
To: amsat-bb@xxxxx.xxxx tjjapha@xxxxxxxxx.xxx
Message-ID: <856593.93953.qm@xxxxxxxx.xxxx.xxx.xxxxx.xxx>
Content-Type: text/plain; charset=us-ascii
How long is your feedline?
Jim
--- On Mon, 11/3/08, ANTHONY JAPHA <tjjapha@xxxxxxxxx.xxx> wrote:
> From: ANTHONY JAPHA <tjjapha@xxxxxxxxx.xxx>
> Subject: [amsat-bb] Preamp advice, pse
> To: amsat-bb@xxxxx.xxx
> Date: Monday, November 3, 2008, 3:45 PM
> Bird Lovers,
> Pse let me have advice on which of the following ARR 2 mtr
> preamps I should get: P144VDA: 1.0db nf, 15 db gain; or
> P144VDG: 0.5db nf, 24db gain.
>
> The preamp will be used primarily for AO-7. I operate only
> portable in a high noise environment here in Manhattan. I
> doubt the nf difference is at all meaningful in my use. The
> large difference in gain between the 2 preamps may not be
> impt. either, that is the real question. My XCVR is the
> FT-817. Another 817 is used to transmit, running abt 15-20
> watts into a small amp. with an Arrow split between 2 booms
> on 2 tripods only abt. 1 ft. from each other.
>
> So what's the verdict?
>
> Tnx and 73,
> Tony, N2UN
>
>
>
> _______________________________________________
> Sent via AMSAT-BB@xxxxx.xxx. Opinions expressed are those
> of the author.
> Not an AMSAT-NA member? Join now to support the amateur
> satellite program!
> Subscription settings:
> http://amsat.org/mailman/listinfo/amsat-bb
------------------------------
Message: 6
Date: Mon, 3 Nov 2008 17:09:48 -0800 (PST)
From: Mark Spencer <mspencer12345@xxxxx.xx>
Subject: [amsat-bb] Re: Preamp advice, pse
To: amsat-bb@xxxxx.xxxx tjjapha@xxxxxxxxx.xxx
Message-ID: <838543.1974.qm@xxxxxxxx.xxxx.xxx.xxxxx.xxx>
Content-Type: text/plain; charset=iso-8859-1
In your application the third order intercept point is probably more important
than gain or noise figure.???? If there is to much gain you can always add an
attenuator to the output.??
?
Depending on the quality of the radio you are using a pre amp may or not?help
in?your application.
?
That said I've been pleased?with the?UHF ARR gasfet preamps and if I was
looking for a VHF?one I'd look at ARR as well.
?
Good luck
?
Mark,
VE7AFZ?
--- On Mon, 11/3/08, ANTHONY JAPHA <tjjapha@xxxxxxxxx.xxx> wrote:
From: ANTHONY JAPHA <tjjapha@xxxxxxxxx.xxx>
Subject: [amsat-bb] Preamp advice, pse
To: amsat-bb@xxxxx.xxx
Received: Monday, November 3, 2008, 6:45 PM
Bird Lovers,
Pse let me have advice on which of the following ARR 2 mtr preamps I should
get: P144VDA: 1.0db nf, 15 db gain; or P144VDG: 0.5db nf, 24db gain.
The preamp will be used primarily for AO-7. I operate only portable in a high
noise environment here in Manhattan. I doubt the nf difference is at all
meaningful in my use. The large difference in gain between the 2 preamps may
not be impt. either, that is the real question. My XCVR is the FT-817.
Another
817 is used to transmit, running abt 15-20 watts into a small amp. with an
Arrow
split between 2 booms on 2 tripods only abt. 1 ft. from each other.
So what's the verdict?
Tnx and 73,
Tony, N2UN
_______________________________________________
Sent via AMSAT-BB@xxxxx.xxx. Opinions expressed are those of the author.
Not an AMSAT-NA member? Join now to support the amateur satellite program!
Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
__________________________________________________________________
Instant Messaging, free SMS, sharing photos and more... Try the new Yahoo!
Canada Messenger at http://ca.beta.messenger.yahoo.com/
------------------------------
Message: 7
Date: 03 Nov 2008 20:14:07 -0600
From: tosca005@xxx.xxx
Subject: [amsat-bb] Re: Yaesu FT-847
To: Luc Leblanc <lucleblanc6@xxxxxxxxx.xx>
Cc: amsat-bb@xxxxx.xxx
Message-ID: <Prayer.1.0.16.0811032014070.14267@xxxx.xx.xxx.xxx>
Content-Type: text/plain; format=flowed; charset=ISO-8859-1
On Nov 2 2008, Luc Leblanc wrote:
>On 2 Nov 2008 at 12:40, Sebastian wrote:
>
>Welcome in the club...
>
> You probably get one of their first model where the CAT system cannot be
> read by PC's he can only received commands from the PC. This problem has
> been corrected on later model..
>
> I just hope your HRD is working as up till now only FT-847 super control
> is working. It's like when you buy the first model of a new car model you
> are stuck with issues time to time on the first version...
Hi, Luc.
My FT-847 was an early production model, and had the incompletely
functioning firmware that prevented bi-directional communication. I sent
mine in for some factory service years ago, and they upgraded the firmware
to the current full-featured version at no extra cost. I don't know for
sure if that is still an option for you, assuming that you have an older
FT-847 like that, from your comment about being "in the club" with an early
model.
As we found out, Sebastian got his problem taken care of, and it wasn't the
firmware problem. I suspected that it would turn out to be something else
(as it did), because in his original posting, he said, "...since Ham Radio
Deluxe can see and control the radio's frequency..." The hallmark of the
old firmware was that the computer could NOT READ the frequency or mode
information, it could only WRITE the frequency or mode to the radio. If HRD
could see the radio's frequency, he had to have the newer firmware. I
didn't chime in right away, since I have absolutely zero first-hand
experience with any of the software he was working with. (Back in the days
when I actually had a little free time, I experimented with writing my own
software to communicate with the FT-847.) I still love the radio and would
not want to part with mine.
73 de W?JT
John P. Toscano, AMSAT-NA LM#2292
------------------------------
Message: 8
Date: Mon, 3 Nov 2008 20:38:10 -0600
From: "Alan" <ve4yz@xxx.xxx>
Subject: [amsat-bb] Re: help with wisp
To: <amsat-bb@xxxxx.xxx>
Message-ID: <706726BC592C4B5B96F8B5B31EFB61D4@xxxxxx>
Content-Type: text/plain; charset="us-ascii"
In defense of WISP32... It works as well in Vista as it did in WIN95, WIN98,
NT4 ( as well as anything ran in NT4 that needed to talk to a comport ),
WIN2000, and XP.
I still use it solely for the GO-32 BBS while running SatPC32 and LVB
Tracker to control the rotator and doppler.
I also occasionally use the olde golde TrakBox. The TrakBox is 15 years old
and I can run doppler and rotator without a PC ( great for Field Day ). The
"current" LVB Tracker goes brain dead every couple of weeks and requires a
recalibration and only does rotators.
Sometimes "new" is not "improved" nor "current".
Lots of great freeware around such as HRD, UI-VIEW32, MMSSTV, and a
bazillion logging programs and more.
If you want to be on the bleeding edge and into open source go to
sourceforge.net and sourceforge.com and do some searches, or, Google
Linux/ham radio.
-----Original Message-----
From: amsat-bb-bounces@xxxxx.xxx [mailto:amsat-bb-bounces@xxxxx.xxxx On
Behalf Of Gordon JC Pearce MM3YEQ
Sent: November 3, 2008 5:06 PM
To: Jeff Wandling W7BRS
Cc: amsat-bb@xxxxx.xxx
Subject: [amsat-bb] Re: help with wisp
Jeff Wandling W7BRS wrote:
> "WiSP for Windows 95/98 or NT 4.0 is current. Written by Chris
> Jackson, ZL2TPO."
WTF? For suitable versions of "current", perhaps!
> WiSP may be obsolete? What version are you running?
I'll say.
It's one of the odd things I've noticed about software for amateur radio,
though. It all seems to be really badly written shareware for old versions
of Windows, with no source code available and quite often a fee required to
"unlock" the useful bits - which, if it hasn't been updated in ten years,
you may not be able to get any more!
I would have thought that radio amateurs would have grokked the concept of
open source, if anyone did...
Gordon
_______________________________________________
Sent via AMSAT-BB@xxxxx.xxx. Opinions expressed are those of the author.
Not an AMSAT-NA member? Join now to support the amateur satellite program!
Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
------------------------------
Message: 9
Date: Mon, 3 Nov 2008 21:39:09 -0500
From: "John Henderson N4NAB" <jah@xx.xx.xxx>
Subject: [amsat-bb] IC-910 and 1296 Board for Sale
To: <amsat-bb@xxxxx.xxx>
Message-ID: <000001c93e26$841f1a40$8c5d4ec0$@xx.xxx>
Content-Type: text/plain; charset="us-ascii"
Like new IC-910 with the UX-910 1296 unit. $1650 plus shipping. Price firm.
All boxes, power cord, mike, manual etc. 10 out of 10 condition. Contact at
n4nab@xxxx.xxx
John
John Henderson N4NAB
212 Bayside Drive
Cape Carteret, NC 28584
------------------------------
Message: 10
Date: Mon, 03 Nov 2008 15:03:06 -0500
From: Luc Leblanc <lucleblanc6@xxxxxxxxx.xx>
Subject: [amsat-bb] Re: Yaesu FT-847
To: amsat-bb@xxxxx.xxx
Message-ID: <490F12AA.27459.1756C7F@xxxxxxxxxxx.xxxxxxxxx.xx>
Content-Type: text/plain; charset=US-ASCII
On 3 Nov 2008 at 8:56, Sebastian wrote:
> Wow, that was easy. I am eternally grateful! It works now. Not an
> intuitive way of programming (IMHO); the documentation states "there
> are 2 combo boxes in the upper left side of the menu. The upper one
> contains the parameters that have to be set (Model, Baud rate), the
> lower one contains the settings available for the selected parameter".
>
> I read that, and read it again, and I thought it was referring to a
> different version of SATPC32, since that description was not clear to
> me, but your explanation was a lot easier to understand. I guess it
> was just a long day, of putting back up my satellite antennas,
> installing new preamps, the radio, etc. Must have made me dizzy doing
> all of that in one day!
>
> And Nate, thanks but I'm aware of how to change the baud rate on the
> radio, the problem was with the software.
>
> And Luc, I don't know what club you are talking about; I don't feel
> that I'm stuck with a radio with problems. Mine was sold to the
> original owner on December 2002, so I don't think it's one of the
> early ones. As far as HRD, it works fine with my 847, but I can't get
> the latest satellite 'test' version (1901) to see either my Kenwood
> TS-2000 or Yaesu FT-847.
>
> 73 de W4AS
> Sebastian
You propbably have a version with the issue corrected or with a serial number
starting with 8G05xxxx
Cat Control Operations
The FT-847 seems to have a set of unique op codes for CAT control. Yaesu in
general, does not appear to have a consistent set of codes for
any of their radios (unlike Kenwood for example).
Given that, you can't select another radio in a software offering that doesn't
show the FT-847 specifically.
The original design for the FT-847 did not include two-way CAT control
operations for frequency and mode. You could use your PC to give
commands to the radio, but the radio could not report back
any frequency or mode information to the PC. Many, including QST, complained
about this shortfall, and the company modified the firmware in
the radio to enable two-way CAT control operations for
frequency and mode. Starting with serial number 8G05xxxx , two-way CAT control
is standard.
In a real credit to Yaesu, it offered to upgrade any earlier model radios to
the two-way CAT control, so many of the earlier models have
two-way CAT control. If you're buying a used FT-847, ask if it has been
upgraded.
The CAT control for the FT-847 does not convey the final digit (i.e., the ones
digit) under any circumstances, so no external software can
ever resolve any frequency better than 10 Hz. The FT-847 itself resolves to 1
Hz.
"-"
Luc Leblanc VE2DWE
Skype VE2DWE
www.qsl.net/ve2dwe
WAC BASIC CW PHONE SATELLITE
------------------------------
Message: 11
Date: Mon, 3 Nov 2008 12:47:54 -0800 (PST)
From: robert@xxxxxxxxxxxxxx.xxx
Subject: [amsat-bb] "off topic" Intelsat Retires the Oldest Commercial
Communications Satellite
To: amsat-bb@xxxxx.xxx
Message-ID: <521093.43968.qm@xxxxxxxx.xxxx.xxx.xxxxx.xxx>
Content-Type: text/plain; charset=us-ascii
I thought this might be of interest to the board. MARISAT F2 was a good bird I
worked her for 2 years from the South Pole. She will be very much missed.
Robert
http://www.marketwatch.com/news/story/Intelsat-Retires-Oldest-Commercial-
Communications/story.aspx?guid={CCEF7D1C-5BD8-450A-8F8D-6697C72A329B}
------------------------------
Message: 12
Date: Mon, 3 Nov 2008 20:07:25 -0800 (PST)
From: TOFFY <hs0nnu@xxxxx.xxx>
Subject: [amsat-bb] Re: GO-32 Status?
To: amsat-bb@xxxxx.xxxx Patrick Domack <patrickdk@xxxxxxxxx.xxx>
Message-ID: <569548.7685.qm@xxxxxxxx.xxxx.xxx.xxxxx.xxx>
Content-Type: text/plain; charset=iso-8859-1
Dear ALL
?
Last night GO-32 max elevation 75 deg. I power on? Rig and Run MixW too late.
I can receive at 40 deg. to LOS.
?
GO-32 20081103 - 1248z
***********************************
4XTECH-12>BEACON>UI,R,F0 (9618 baud):
4XTECH-11>PBLIST>UI,R,F0 (9622 baud):
PB: Empty.
4XTECH-11>PBLIST>UI,R,F0 (9622 baud):
PB: Empty.
4XTECH-12>BBSTAT>UI,R,F0 (9620 baud):
Open:AB1C23:
4XTECH-12>BEACON>UI,R,F0 (9620 baud):
Upl:145.89,1269.8
?
73's de Toff
HS0NNU
?
--- On Tue, 11/4/08, Patrick Domack <patrickdk@xxxxxxxxx.xxx> wrote:
From: Patrick Domack <patrickdk@xxxxxxxxx.xxx>
Subject: [amsat-bb] Re: GO-32 Status?
To: amsat-bb@xxxxx.xxx
Date: Tuesday, November 4, 2008, 12:43 AM
It's been up for 1 or 2days now. So I guess it's been recovered
(sorry didn't hit the reply to list button last time)
Quoting Robert Bruninga <bruninga@xxxx.xxx>:
> GO32 has not been recently reloaded, so presumably it is in safe
> mode until a receovery effort is made by the command team in
> Israel. At present, we don't know how long it will be until a
> recovery effort is made.
>
> Bob
>
>> -----Original Message-----
>> From: amsat-bb-bounces@xxxxx.xxx
>> [mailto:amsat-bb-bounces@xxxxx.xxxx On Behalf Of John Ronan
>> Sent: Monday, November 03, 2008 4:28 AM
>> To: AMSAT-BB BB
>> Subject: [amsat-bb] GO-32 Status?
>>
>> Morning,
>>
>> I attempted to use GO-32 last night and didn't have much
> success.
>> Its been a while since I tried it so I was wondering if there
> is
>> something amiss with the sat? Or if I should keep checking
> items on
>> my station.
>>
>> I was unable to beacon an APRS packet through on 145.850 at
> all
>> (using software), neither was a colleague able to on 145.930
> with a
>> TM-D700
>>
>> I've seen a few previous posters ask a similar question, but
> I've
>> not managed to find a definitive reply.
>> Regards
>> John
>>
>>
>> --
>> John Ronan <jronan@xxxx.xxx>, +353-51-302938
>> Telecommunications Software & Systems Group,
> http://www.tssg.org
>>
>>
>>
>> _______________________________________________
>> Sent via AMSAT-BB@xxxxx.xxx. Opinions expressed are those of
>> the author.
>> Not an AMSAT-NA member? Join now to support the amateur
>> satellite program!
>> Subscription settings:
> http://amsat.org/mailman/listinfo/amsat-bb
>>
>
> _______________________________________________
> Sent via AMSAT-BB@xxxxx.xxx. Opinions expressed are those of the author.
> Not an AMSAT-NA member? Join now to support the amateur satellite program!
> Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
>
_______________________________________________
Sent via AMSAT-BB@xxxxx.xxx. Opinions expressed are those of the author.
Not an AMSAT-NA member? Join now to support the amateur satellite program!
Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
------------------------------
Message: 13
Date: Mon, 3 Nov 2008 21:19:09 -0700
From: "Dave" <dave@xxxxxx.xxx>
Subject: [amsat-bb] GS-5500
To: <AMSAT-BB@xxxxx.xxx>
Message-ID: <37C8EE8EC8CB4C0993DF52680D4087F8@xxxxxxxxxxxxxx>
Content-Type: text/plain; charset="iso-8859-1"
Hi group,
I have a GS-5500 and both 2m and 70cm (436CP) M-squared antennas. I see a lot
of traffic about problems with interconnects between radios and software, so I
thought I'd ask what a really nice workable combo would be.
What radio works nice with Sat32PC when doing various satellite work? Should I
get two radios, one for each band?
73,
Dave
------------------------------
Message: 14
Date: Tue, 4 Nov 2008 07:31:29 +0100
From: "i8cvs" <domenico.i8cvs@xxx.xx>
Subject: [amsat-bb] Re: Preamp advice, pse
To: <tjjapha@xxxxxxxxx.xxx>, "AMSAT-BB" <amsat-bb@xxxxx.xxx>
Message-ID: <000d01c93e46$f9e161a0$0201a8c0@xxx.xx>
Content-Type: text/plain; charset="iso-8859-1"
----- Original Message -----
From: "ANTHONY JAPHA" <tjjapha@xxxxxxxxx.xxx>
To: <amsat-bb@xxxxx.xxx>
Sent: Tuesday, November 04, 2008 12:45 AM
Subject: [amsat-bb] Preamp advice, pse
> Bird Lovers,
> Pse let me have advice on which of the following ARR 2 mtr preamps I
should get: P144VDA: 1.0db nf, 15 db gain; or P144VDG: 0.5db nf, 24db gain.
>
> The preamp will be used primarily for AO-7. I operate only portable in a
> high noise environment here in Manhattan. I doubt the nf difference is at
> all meaningful in my use. The large difference in gain between the 2
> preamps may not be impt. either, that is the real question. My XCVR is
> the FT-817. Another 817 is used to transmit, running abt 15-20 watts into
> a small amp. with an Arrow split between 2 booms on 2 tripods only abt. 1
> ft. from each other.
>
> So what's the verdict?
>
> Tnx and 73,
> Tony, N2UN
>
Hi Tony, N2UN
Do you remember our QSO via FO-29 on 21 april 2008 ? You writes to to me
> Domenico
> I thought you might like to see a photo of the station used to make our
> QSO. It is attached. The Triborough Bridge and Hell Gate Bridge are in
> the background. The station is on a promenade next to the East River, 2
> miles north of the United Nations.
> 73,
> Tony
I am looking at the photo of your location and I see that you are living in
an urban area in which the man made noise temperature at 145 MHz is at
best a minimum of 10.000 kelvin
The sensitivity of a FT-817 at 144 MHz is specified to be 0.25 uV but the
manufacturer do not refere for what ratio in dB
Supposing that the sensitivity is 0.25 uV for a S/N ratio of 10 dB then the
corresponding computed Noise Figure of a FT-817 is 11 dB at 144 MHz
corresponding to a noise temperature of 3360 kelvin
Assuming from the photo that you are using 10 feet only of RG213 to connect
the output of your preamplifier to the input of your FT-817 then the loss
of 0.25 dB at 145 MHz introduced by the above coax cable can be omitted
in our calculation.
If you use a preamplifier with NF= 1 dB and Gain 15 dB in front of your
FT-817 then the overall Noise Figure of your receiving system becomes
2 dB corresponding to a noise temperature of 170 kelvin
If you use a preamplifier with NF= 0.5 dB and Gain = 24 dB in front of
your FT-817 then the overall Noise Figure of your receiving system becomes
0.7 dB corresponding to a noise temperature of 51 kelvin
The improvement in S/N using a FT-817 with in front of it a preamplifier of
NF= 0.5 dB versus a preamplifier with NF = 1 dB in the New York City area
with a man made noise of 10.000 kelvin will be only
(10.000 + 170) / ( 10.000 + 51) = 0.05 dB i.e. a insignificant improvement.
You cannot see the improvement between preamplifiers because the man made
noise of 10.000 kelvin on your antenna predominates but if you go in a
country location where the man made noise is only 200 kelvin at 145 MHz then
the improvement in S/N using your FT-817 with a 0.5 dB NF preamplifier
versus a 1 dB NF preamplifier will rise to (200 + 170) / (200/ 51) = 1.7 dB
In conclusion using preamplifiers with 0.5 dB or 1 dB Noise Figure in front
of a FT-817 in the New Yok City area the advantage is basically ZERO but it
rises to 1.7 dB if you go in the country area very far from the city.
On the other side:
If you use the FT-817 alone in New York City area versus the FT-817 + the
preamplifier with NF= 1 dB then the improvement in S/N will be
(10.000 + 3360 ) / ( 10.000 + 170 ) = 1.18 dB
If you use the FT-817 alone in New York City versus the FT-817 + the
preamplifier with NF= 0.5 dB then the improvement will be
(10.000 +3360) / ( 10.000 + 51) = 1.23 dB
You cannot see too much difference with or not preamplifier because again
here the antenna temperature of 10.000 kelvin in New York City predominates
and again the improvement with one or the other preamplifier is only
1.23-1.18 = 0.05 dB i.e. inexistent
But if you go in a country area where the man made noise is only 200 kelvin
then the improvement in S/N using a FT-817 alone versus a FT-817 + in front
of it a 1 dB NF preamplifier will rise to : (200 + 3360) / ( 200 + 170) = 10
dB wich is a great improvement ! !
Identically if in a country area you use a FT-817 alone versus a FT-817 + in
front of it a 0.5 dB NF preamplifier then the improvement in S/N will rise
to (200 + 3360 ) / ( 200 + 51) = 11. 5 dB
In this situation where the antenna temperature do not predominates then
the difference in the improvements 11.5-10 = 1.5 dB is greater than the
difference between the Noise Figure of the preamplifiers 1-0.5 = 0.5 dB
In conclusion since using a FT-817 with a 0.5 dB NF preamplifier In the New
York City area the improvement in S/N versus the FT-817 alone is only
1.23 dB I suggest you do not use a preamplifier but to use an antenna with a
greater gain of at least 3 dB
I hope to contact you via AO-7 wich is easier than our previous QSO via
FO-29
73" de
i8CVS Domenico
------------------------------
Message: 15
Date: Mon, 03 Nov 2008 22:23:17 -0900
From: Edward Cole <kl7uw@xxxxxxxxx.xxx>
Subject: [amsat-bb] Re: Preamp advice, pse
To: tjjapha@xxxxxxxxx.xxxx amsat-bb@xxxxx.xxx
Message-ID: <200811040723.mA47NHcG018763@xxxx.xxxxxxxxx.xxx>
Content-Type: text/plain; charset="us-ascii"; format=flowed
At 02:45 PM 11/3/2008, ANTHONY JAPHA wrote:
>Bird Lovers,
>Pse let me have advice on which of the following ARR 2 mtr preamps I
>should get: P144VDA: 1.0db nf, 15 db gain; or P144VDG: 0.5db nf, 24db gain.
>
>The preamp will be used primarily for AO-7. I operate only portable
>in a high noise environment here in Manhattan. I doubt the nf
>difference is at all meaningful in my use. The large difference in
>gain between the 2 preamps may not be impt. either, that is the real
>question. My XCVR is the FT-817. Another 817 is used to transmit,
>running abt 15-20 watts into a small amp. with an Arrow split
>between 2 booms on 2 tripods only abt. 1 ft. from each other.
>
>So what's the verdict?
>
>Tnx and 73,
>Tony, N2UN
Hard to advise you since I live in rural Alaska....but:
I have used both preamps in a slightly different use (eme). The
GasFet P144VDG is really nice to get the NF down and has sufficient
gain to be used at the antenna with a long run of RG-58 to the
radio. But in the RF contaminated environ of Manhattan the P144VDA
may work as well (or better due to the high noise floor).
I use the P144VDA as my second preamp in my 2m-eme system to increase
the gain of my mgf-1801 preamp since it has 16.8 dB gain and I need a
minimum of 22 dB gain before the FT-847. The result is = 16.8 + 15 -
1.8 - 0.5 = 29.5 dB. The last two items are my Rx line loss of
150-feet of LMR-400 and line filter loss.
The P144VDA uses a 3SK48 MOSFet which is quite tolerant of high
levels of RF and that makes it a fine second preamp.
So I would say if your line loss were under 2-dB the P144VDA will be
OK. The P144VDG will work great if it is not subject to high out of band RFI.
***********************************************************
73, Ed - KL7UW BP40iq, 6m - 3cm
144-EME: FT-847, mgf-1801, 4x-xp20, 185w
1296-EME: DEMI-Xvtr, 0.30 dBNF, 4.9m dish, 60W
http://www.kl7uw.com AK VHF-Up Group
NA Rep. for DUBUS: dubususa@xxxxxxx.xxx
***********************************************************
------------------------------
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Sent via amsat-bb@xxxxx.xxx. Opinions expressed are those of the author.
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End of AMSAT-BB Digest, Vol 3, Issue 571
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