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CX2SA > SATDIG 03.07.08 00:06l 240 Lines 8765 Bytes #999 (0) @ WW
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Sent: 080702/2212Z @:CX2SA.LAV.URY.SA #:14748 [Minas] FBB7.00e $:14748_CX2SA
From: CX2SA@CX2SA.LAV.URY.SA
To : SATDIG@WW
Today's Topics:
1. Re: Commercial Mode L Antenna sources (John Price)
2. Re: Best type of coax to use between preamps and antennas
(hasan schiers)
3. Re: Commercial Mode L Antenna sources (Wayne Estes)
----------------------------------------------------------------------
Message: 1
Date: Wed, 2 Jul 2008 12:47:59 -0400
From: "John Price" <n4qwf1@gmail.com>
Subject: [amsat-bb] Re: Commercial Mode L Antenna sources
To: APBIDDLE@mailaps.org, "amsat-bb@amsat.org" <amsat-bb@amsat.org>
Message-ID:
<8d1b8e80807020947k7a270519jb87cbd1f05f1bdaf@mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1
I used Directtive Systems model 2314LYRM 14 ELEMENT rear mount 36 INCH
15 dBi gain loop yagi for the past 2 field days. Feed it with 80 feet
of Andrews 1/2 inch hardline. I had a 6 foot jumper of RG8 from the
antenna to the hardline to do the twist. Also a 8 foot piece of the
same RG8 at the radio end as it just did not quit reach.
I tested this with the IC-1200 before the big day. I saw 23 watts at
the radio and 13 at the antenna using the Bird. Lord knows that is
enough to work AO-51 anytime.
Thanks W4AMC for the mode L/u contact. GD sig.
73's << John
On Wed, Jul 2, 2008 at 8:15 AM, Alan P. Biddle <APBIDDLE@united.net> wrote:
> Ron,
>
> I have an M2 23CM35EZ which works very well with AO-51. Overkill on AO-51,
> and probably marginal for P3, though they are easy to stack for gain.
> http://www.m2inc.com/products/uhf/23cm/23cm35ez.html
>
> If you want to go with a commercial helix, Directive Systems makes the
> DSH23-12. A friend bought one, and in fact got them to make one with a few
> more turns in it. It worked well, and is certainly designed to withstand
> the elements. http://www.directivesystems.com/new.htm
>
> Alan
> WA4SCA
>
>
>
>
> _______________________________________________
> Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author.
> Not an AMSAT-NA member? Join now to support the amateur satellite program!
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--
N4QWF Amateur Radio Operator
AO-7,AO-16,AO-27,SO-50,AO-51,VO-52
Internet N4QWF@AMSAT.ORG
Echolink node #110903
Formerly KC4AHW VK3FEZ
Amsat Member #27845
DXCC #33,478
VUCC SAT #135
WAS SAT #296
51 on 51 #13
LON -79.256 LAT 37.459 Grid FM07il
>From the Foothills of the Blueridge
*Life should not be a journey to the grave with the intention of
arriving safely in a pretty and well preserved body, but rather to
skid in broadside, thoroughly used up, totally worn out, and loudly
proclaiming - "WOW, What a ride!"
------------------------------
Message: 2
Date: Wed, 02 Jul 2008 11:49:50 -0500
From: hasan schiers <schiers@netins.net>
Subject: [amsat-bb] Re: Best type of coax to use between preamps and
antennas
To: Joe <nss@mwt.net>
Cc: amsat-bb@amsat.org
Message-ID: <486BB1AE.3060908@netins.net>
Content-Type: text/plain; charset="iso-8859-1"
As Dom noted in another post, any loss ahead of the preamp detracts from
the NF of the preamp (which you paid good money to get as low as
possible). Throwing that away by using small/cheap cable is not a wise
investment when relatively inexpensive low loss (preserving the NF)
cables are readily available. If you plug the losses of a 15 ft run of
smaller coax into a link budget calculator (referenced in this forum
many times), you will be astounded at how much your sensitivity drops by
placing these kinds of losses ahead of a 0.2 or 0.5 dB NF preamp.
...hasan, N0AN
Joe wrote:
> Thing is with that short of a run,
> any of the smaller coaxes will work just fine and he'd never know the
> difference 10 to 15 feet anything will work!
>
> hasan schiers wrote:
>
>> LMR-400 works very well, and for higher flexibility requirements, you
>> can use LMR-400 ultra flex.
>> It's loss is very close to 9913, without some of the 9913 varieties
>> problems. I replaced all my 9913 with LMR-400 years ago, and all my
>> water problems went away, never to return.
>>
>> 73,
>>
>> hasan, N0AN
>>
>> Ronald Nutter wrote:
>>
>>> 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@amsat.org. Opinions expressed are those of the
>>> author.
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>> _______________________________________________
>> Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author.
>> Not an AMSAT-NA member? Join now to support the amateur satellite
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------------------------------
Message: 3
Date: Wed, 02 Jul 2008 12:33:49 -0500
From: Wayne Estes <w9ae@charter.net>
Subject: [amsat-bb] Re: Commercial Mode L Antenna sources
To: amsat-bb@amsat.org
Message-ID: <486BBBFD.5050802@charter.net>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
I'm surprised how few people have mentioned parabolic dishes during this
discussion about commercial Mode L antennas. L-band uplinks are mostly
used in combination with a S-band downlink. Most people build L/S
equipment with HEO satellites in mind. A single yagi or helix doesn't
usually provide sufficient gain for L/S band use with a HEO satellite.
You need the gain of a dish for satisfactory S-band reception of a HEO
satellite. So one practical solution is an oversized dish with a L/S
dual-band feed (helix or patch). A 4-foot dish was proven to work well
for this on AO40. In my opinion a single 4-foot dish is more practical
than, for example, cobbling together multiple yagi/helix antennas for
S-band downlink and multiple yagi/helix antennas for L-band uplink.
My 4-foot dish and dual-band patch feed were purchased commercially from
Teksharp (Rick Fletcher KG6IAL).
http://www.plumdragon.com/teksharp/hr_AO-40_products.htm
The dual-band patch feed is sold fully assembled and tested, but the
dish was a kit. I had to locally purchase 1/4 inch hardware cloth, cut
it into 8 "petals", and use 200 zip ties to attach the petals to the
frame of the dish. A mesh dish has somewhat less wind loading than a
solid dish. That's important because a solid 4-foot dish has a maximum
wind load of more than 12 square feet, exceeding the wind load rating of
my G-5500 rotor. A picture of my satellite antennas can be seen here:
http://s238.photobucket.com/albums/ff239/Wayne_Estes/Ham%20Radio/
Wayne Estes W9AE
Oakland, Oregon, USA, CN83ik
------------------------------
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Sent via amsat-bb@amsat.org. Opinions expressed are those of the author.
Not an AMSAT member? Join now to support the amateur satellite program!
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End of AMSAT-BB Digest, Vol 3, Issue 329
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