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CX2SA > SATDIG 02.07.08 01:00l 417 Lines 14609 Bytes #999 (0) @ WW
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To : SATDIG@WW
Today's Topics:
1. Re: Eliminating Desensing (Edward Cole)
2. Re: Best type of coax to use between preamps and antennas
(Alan P. Biddle)
3. Re: Best type of coax to use between preamps and antennas
(Jim Danehy)
4. 2008 Field Day Submissions (Bruce)
5. Re: APRS FD (Robert Bruninga)
6. SEEDS-II heared in FM packet ! (Henk, PA3GUO)
7. Re: Best type of coax to use ... in ... AMSAT-BB Digest, Vol
3, Issue 326 (joe cassano aka jmario)
----------------------------------------------------------------------
Message: 1
Date: Mon, 30 Jun 2008 21:55:09 -0800
From: Edward Cole <kl7uw(AT)acsalaska.net>
Subject: [amsat-bb] Re: Eliminating Desensing
To: Andrew Glasbrenner <glasbrenner(AT)mindspring.com>, "Reicher,James"
<JReicher(AT)hrblock.com>, amsat-bb(AT)amsat.org
Message-ID: <200807010555.m615tAdg065063(AT)hermes.acsalaska.net>
Content-Type: text/plain; charset="iso-8859-1"; format=flowed
Andrew is onto something when he suggests
different preamp sensitivities to out of band
interference. One can also just have front-end oveload of energy on
frequency.
I have not had any issues with either Mode-UV or
Mode-VU with my system where the antennas are
separated 5-feet on a metal boom. My preamps
both sue mgf-1302 GasFets. Both were special designs and not commercial mfrs.
But I will say that ARR preamps seem to work well
as do Kuhne Engineering (DB6NT) designs.
The diplexer solution works for out of band
interference when used in front of the
preamp. In band front-end blockage can be
handled by filtering the transmit coax line
either with a bandpass filter or 1/4 wave coax
stub tuned for the receive frequency.
Often it takes a bit of trial and error to find
the solution for your particular situation.
73 Ed - KL7UW
At 09:22 AM 6/30/2008, Andrew Glasbrenner wrote:
>It's unusual to see desense on 2m receive from a
>70cm uplink, but I think the same solution can
>be applied. Many use a common 2m/70cm diplexer
>as a high pass/low pass filter. In this case you
>would want to feed the 2m antenna to the common
>port of the diplexer, and the 2m port of the
>diplexer to the input of either your preamp or
>rig if you do not have a preamp. This blocks
>your transmitted signal from the receiver/preamp
>input very effectively.
>http://www.amsat.org/amsat-new/articles/Mode-J/
>describes this for 70cm desense issues. Another
>option is to use a preamp with good filtering on
>the input. I had issues with Mode J desense with
>my Icom AG-35 preamp, but have none now that I
>have switched to SSB Electronics preamps. As
>always, Your Mileage May Vary (YMMV). 73, Drew
>KO4MA -----Original Message----- >From:
>"Reicher, James" <JReicher(AT)hrblock.com> >Sent:
>Jun 30, 2008 12:50 PM >To:
>amsat-bb(AT)amsat.org >Subject:
>[amsat-bb] Eliminating Desensing > >I got
>significant de-sensing of my 2 meter downlink
>from my 70cm uplink at Field Day. I know a good
>part of it was due to the short cross-boom
>(about 4 feet) I was using. I would like to
>decrease the de-sense on this set-up before I
>permanently install it at my home station. Any
>and all suggestions are welcome. > >73 de W0HV,
>Jim in Raymore, MO? >Light travels faster than
>sound... This is why some people appear bright
>until you hear them
>speak. > >_______________________________________
>________ >Sent via AMSAT-BB(AT)amsat.org. 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(AT)amsat.org. 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: 2
Date: Tue, 1 Jul 2008 02:46:14 -0500
From: "Alan P. Biddle" <APBIDDLE(AT)UNITED.NET>
Subject: [amsat-bb] Re: Best type of coax to use between preamps and
antennas
To: <amsat-bb(AT)amsat.org>
Message-ID: <24D8F96797C9431088063E0AB38AE084(AT)WA4SCA>
Content-Type: text/plain; charset="us-ascii"
Ron,
There are a variety of flexible, low loss cables. Over a 10-15 foot length
the differences in loss would be inconsequential. Probably the most
important factor is that it has excellent shielding, and preferably double
shielding, to prevent pickup between the RX and TX bands. Over the years I
have used RG-213, Davis Bury-Flex, LMR-400UF, and probably AirCom around the
rotators. I have used the original "water pipe" 9913 only, but I suspect
the modern flexible version would be fine as well. Even with heavy use back
in the pacsat and HEO days, I have never had a failure of a cable, except
for one of my bad connector installations where I did not provide proper
strain relief.
Alan
WA4SCA
------------------------------
Message: 3
Date: Tue, 1 Jul 2008 08:33:05 -0400
From: "Jim Danehy" <jdanehy(AT)cinci.rr.com>
Subject: [amsat-bb] Re: Best type of coax to use between preamps and
antennas
To: "Ronald Nutter" <rnutter(AT)networkref.com>, <amsat-bb(AT)AMSAT.Org>
Message-ID: <E94B7968307541A4B8AD1DCFF9267E69(AT)JamesPC>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
reply-type=response
Ron
Did you diagnose what your problem was ? Water in the coax ? Where is your
preamp mounted ? If very near (10 feet) the antenna you can use RG8. If you
feel intimidated by N connectors (many folks are), Henry Radio and others
sell a two (2) piece N connector that is installed much like a PL 259 which
you have probably installed many times. Check out Henry Radio on Ebay. If
you need more info on this email me direct. I think they get around $4 a
connector. A short run (10 ft) of RG8 at 432mhz or 144mhz is not too
prohibited, in my opinion. Or you can have somebody put together a jumper as
you have noted. Self reliance provides better quality control in my opinion.
Jim W9VNE
----- Original Message -----
From: "Ronald Nutter" <rnutter(AT)networkref.com>
To: <amsat-bb(AT)amsat.org>
Sent: Monday, June 30, 2008 8:49 PM
Subject: [amsat-bb] Best type of coax to use between preamps and antennas
> After problems I had on Field Day in trying to operate the satellites, I
> am looking to upgrade the coax I use between the preamps and the antennas.
> I am using 9913FX from the IC-910H and the preamps. I had been using RG
> Mini 8/U for the connection between the preamps and antennas. Should I
> also use 9913FX between the preamps and the antennas? The run between the
> radio and the preamp is 50 ft. The run from the preamp to the antennas is
> about 10 - 15 ft depending on where I set the antennas up. I am concerned
> about how flexible the 9913FX would be in terms of the antennas rotating
> back and forth. I was planning on ordering the cables pre-made from
> CableXperts since working with N connectors isnt my strong point and dont
> want to worry about my soldering and having a good connection on both ends
> of the cable.
>
> Any suggestions appreciated.
>
> Thanks,
> Ron
> KA4KYI
>
>
------------------------------
Message: 4
Date: Tue, 01 Jul 2008 08:47:14 -0500
From: Bruce <kk5do(AT)arrl.net>
Subject: [amsat-bb] 2008 Field Day Submissions
To: "amsat-bb(AT)AMSAT.Org" <amsat-bb(AT)amsat.org>
Message-ID: <486A3562.1020006(AT)arrl.net>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Now that field day is over for 2008, there is one more thing that you
have to take care of. Submitting your contacts for scoring under the
AMSAT rules. You can download the rules from
http://www.amsatnet.com/2008fd.pdf
or
http://www.amsatnet.com/2008fd.doc
Below are the important dates and emailing/mailing information.
73...bruce
The Satellite Summary Sheet should be used for submission of the AMSAT
Field Day competition and be received by KK5DO (email or postal mail) by
11:59 P.M. CDT, Monday, July 14, 2008. The preferred method for
submitting your log is via e-mail to kk5do(AT)amsat.org or kk5do(AT)arrl.net.
You may also use the postal service but give plenty of time for your
results to arrive by the submission date. Add photographs or other
interesting information so that can be used an article for the Journal.
*You will receive an email back (within one or two days) from me when I
receive your email submission. If you do not receive a confirmation
message, then I have not received your submission. Try sending it again
or send it to my other email address. ***
If mailing your submission, the address is:
Bruce Paige, KK5DO
Director of Awards and Contests
PO Box 310
Alief, TX 77411-0310
--
Bruce Paige, KK5DO
AMSAT Director Contests and Awards
ARRL Awards Manager (WAS, 5BWAS, VUCC), VE
Houston AMSAT Net - Wed 0100z on SkyScanner Satellite Radio Network on Galaxy-
25 (AT)97? West,
Transponder 23 (12115 Vert), Symbol Rate: 22425, APID: 1794 (DVB Free To Air)
Also streaming MP3 at http://www.amsatnet.com
Podcast at http://www.amsatnet.com/podcast.xml or iTunes
Latest satellite news on the ARRL Audio News
http://www.arrl.org
------------------------------
Message: 5
Date: Tue, 1 Jul 2008 11:32:38 -0400
From: "Robert Bruninga" <bruninga(AT)usna.edu>
Subject: [amsat-bb] Re: APRS FD
To: "'Stu'" <stu(AT)stu2.net>, <amsat-bb(AT)AMSAT.Org>
Message-ID: <1EA224BBA48F4B1B914506F8610E3F2E(AT)ewlab.usna.edu>
Content-Type: text/plain; charset="us-ascii"
> Are there any success stories for APRS and FD?
Two topics:
TOPIC 1 GO32: Yours truly blew it. I was the main man at
setting up an all new FD site right in the middle of the tourist
capital of Maryland (Annapolis City dock). Talk about public
exposure! See
http://www.ew.usna.edu/~bruninga/field-day2008.html
Our FD score was inversly proportional to our HIGH score at
talking to the public. I missed every pass on Saturday evening,
but was focused on GO-32 for the overhead pass on Sunday
morning. Put the ARROW on a tripod so I could conccentrate on
messaging... Figured GO32 was stong enough...
Nothing heard... With enough unknowns, different laptop, etc, I
didn't try different polarizations until late in the pass. Duh,
I knew GO32 was gravity stabilized, darned if I didn't have my
arrow horizontal on UHF! Too late. Maybe someone got my
uplink, but I heard nothing... Till the very end and by then it
was too low..
TOPIC 2, GLOBAL GROUPS: But I made dozens and dozens of APRS
contacts on the terrestrial system using the new APRS CQSRVR.
AMSAT folks involved in large area experiments might conisder
using this new global group messaging capabiltity for large area
coordination. Using only your APRS radio, you can be in
communication with all other APRS people in your group. For
example, everyone could send a message to a group named "AMSAT"
and then everyone else in that group (anywhere in the world)
would get that message live.
Might be useful for launch campaigns... See the web page:
http://www.ew.usna.edu/~bruninga/cqsrvr.html
Bob, WB4APR
------------------------------
Message: 6
Date: Tue, 1 Jul 2008 19:25:34 +0200 (CEST)
From: "Henk, PA3GUO" <hamoen(AT)iae.nl>
Subject: [amsat-bb] SEEDS-II heared in FM packet !
To: <amsat-bb(AT)amsat.org>
Message-ID: <3294.212.61.85.173.1214933134.squirrel(AT)webmail.iae.nl>
Content-Type: text/plain; charset=iso-8859-1
Picked up the last part of a pass of SEEDS-II today.
Satellite was in FM 1k2 packet mode.
First time that I heared this mode over Europe.
Freq: 437.485 MHz.
Radio: TS2000, 2x8 elements antenna, no pre-amp.
Here is how it sounds like (12 seconds / 50kb):
http://home.vianetworks.nl/users/hamoen/pa3guo/seeds_01jul08_1115utc_pa3guo_pa
cket_437.485.mp3
JQ1YGU*>JQ1YGV
F0 F9 61 05 28 00 00 40 D7 00 00 00 01
00 01 00 01 00 00 00 00 0B 43 0B 88 0A
10 0B 97 0B 27 0B 68 00 05 00 08 00 06
00 04 00 05 00 06 0C 7D 0F FD 08 3C 07
8F 0B 10 10 A7 08 B8 07 E4 09 2A 09 30
08 04 08 77 88 C1 09 58 08 D8 09 85
Henk, PA3GUO
The Netherlands
www.pa3guo.com
------------------------------
Message: 7
Date: Tue, 01 Jul 2008 13:38:01 -0400
From: joe cassano aka jmario <jmario(AT)fast.net>
Subject: [amsat-bb] Re: Best type of coax to use ... in ... AMSAT-BB
Digest, Vol 3, Issue 326
To: amsat-bb(AT)amsat.org
Message-ID: <486A6B79.1090307(AT)fast.net>
Content-Type: text/plain; charset=us-ascii; format=flowed
Installing a classic clamp type N connector like the Amphenol 82-202
(UG-21D/U) on flexible coax with a real copper center conductor
(RG-8,RG-213) is both easier and has a much higher probability of
success than installing the common PL-259. You only have to make one
easily accessible solder connection.
Take a look at
http://www.amphenolrf.com/products/assemblyInstructions/280.pdf to see
what is involved in attaching classic clamp style N connector.
You also might want to read the reviews listed here:
http://www.eham.net/reviews/products/7 before you make any purchase
decisions.
Regards,
JoeC - K3FMA
> ------------------------------
>
> Message: 12
> Date: Mon, 30 Jun 2008 19:49:00 -0500
> From: Ronald Nutter <rnutter(AT)networkref.com>
> Subject: [amsat-bb] Best type of coax to use between preamps and
> antennas
> To: amsat-bb(AT)amsat.org
> Message-ID: <48697EFC.5010100(AT)networkref.com>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
> After problems I had on Field Day in trying to operate the satellites, I
> am looking to upgrade the coax I use between the preamps and the
> antennas. I am using 9913FX from the IC-910H and the preamps. I had
> been using RG Mini 8/U for the connection between the preamps and
> antennas. Should I also use 9913FX between the preamps and the
> antennas? The run between the radio and the preamp is 50 ft. The run
> from the preamp to the antennas is about 10 - 15 ft depending on where I
> set the antennas up. I am concerned about how flexible the 9913FX would
> be in terms of the antennas rotating back and forth. I was planning on
> ordering the cables pre-made from CableXperts since working with N
> connectors isnt my strong point and dont want to worry about my
> soldering and having a good connection on both ends of the cable.
>
> Any suggestions appreciated.
>
> Thanks,
> Ron
> KA4KYI
>
>
------------------------------
_______________________________________________
Sent via amsat-bb(AT)amsat.org. Opinions expressed are those of the author.
Not an AMSAT member? Join now to support the amateur satellite program!
http://amsat.org/mailman/listinfo/amsat-bb
End of AMSAT-BB Digest, Vol 3, Issue 327
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