[amsat-bb] Re: AMSAT-BB Digest, Vol 2, Issue 840

Wed Dec 26 14:06:03 PST 2007

Try to reduce the comunication bit rate to minimum, it helped for me with
the 857
73
Peleg 4x1gp

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Sent: Wednesday, December 26, 2007 10:00 PM
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Subject: AMSAT-BB Digest, Vol 2, Issue 840

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Today's Topics:

   1. Re: RigExpert Tiny to Yaesu FT-847 (Alan P. Biddle)
   2. Re: Questions on physically offset CP yagi feeding (i8cvs)
   3.  Yaesu FT-897 and HRD satellite tracking problem (Dave Matthews)
   4.  Ande. (John Ronan)
   5. Re: Yaesu FT-897 and HRD satellite tracking problem
      (Simon Brown (HB9DRV))

----------------------------------------------------------------------

Message: 1
Date: Tue, 25 Dec 2007 15:19:41 -0600
From: "Alan P. Biddle" <APBIDDLE at UNITED.NET>
Subject: [amsat-bb] Re: RigExpert Tiny to Yaesu FT-847
To: "'Amsat-Bb'" <amsat-bb at amsat.org>
Message-ID: <000001c8473b$dd3f60e0$6401a8c0 at WA4SCA>
Content-Type: text/plain;	charset="us-ascii"

Rod,

Take a look at http://www.usinterface.com/naviusa_007.htm for a wide variety
of cables for the full RigExpert.  (The Navigator uses the same pin out.)
They should give you some good ideas for the Tiny.  Note that the FT-847 has
the cables for the PKT and DATA ports wired in parallel, so you will need
swap the plugs depending on what mode you are operating.  Or, as I did, wire
up a simple AB switch.  Note that for the PKT connection to use the 1200
baud RX.  Several of the RE sites have the wiring incorrectly using the 9600
baud output.  It will work, somewhat, but with a very poor S/N.  The
interface will not handle 9600 baud.  

73s,

Alan
WA4SCA

------------------------------

Message: 2
Date: Wed, 26 Dec 2007 00:04:29 +0100
From: "i8cvs" <domenico.i8cvs at tin.it>
Subject: [amsat-bb] Re: Questions on physically offset CP yagi feeding
To: "jonny 290" <jonny290 at gmail.com>, "AMSAT-BB" <amsat-bb at amsat.org>
Message-ID: <001d01c8474a$815a7440$0201a8c0 at tin.it>
Content-Type: text/plain;	charset="iso-8859-1"

----- Original Message -----
From: "jonny 290" <jonny290 at gmail.com>
To: <amsat-bb at amsat.org>
Sent: Monday, December 24, 2007 10:59 PM
Subject: [amsat-bb] Questions on physically offset CP yagi feeding

> I've decided to rebuild my 2m antenna and have a couple of questions.
>
> My thinking is to build a six element wide-band 50 ohm match yagi and 
> mount the vertically polarized elements 1/4 wavelength ahead of the 
> horizontal ones, and feed the elements in phase.

Hi Matt, KC4YLV

Mounting the vertical and horizontal elements with an offset of 1/4
wavelength over the boom is good because feeding the driven elements in
phase you get almost a one sense CP without adding delay lines.
.
> I have
> examined the possibility of masthead CP phasing, but am concerned 
> about mismatching and like the arguments given for the physically 
> offset, in-phase fed elements.

There are masthead CP phasing and switching circuits with a minimum of
mismatching and in addition the lenght of  coax relays is not to be taken
into account because the length of relays is compensated for provided all
relays are of the same type and the same lenght.
As an example using 4 coax relays of the same type antenna mounted you can
switch from the shack V-H-RHCP and LHCP as described into the AMSAT-Journal
march/april 2007 and may/june 2007
>
> My antenna to radio coax run is right around 30 feet. I am thinking of 
> running two lengths of LMR-240, speced at 3 dB loss/100ft, so loss 
> should be about 1 dB. If I cut the two feedlines to identical lengths, 
> I should be able to connect them with a coax tee in the shack and use 
> a
> 1/4 wave 37 ohm line to bring the system impedance back up from 25 (at 
> the tee) to 50 ohms.

This is correct but you must be able to exactly cut two runs of coax cable
30 feet long and having the same electrical lenght and first of all it is
good to use both coax lines coming from the same coil and if you have access
to a network analyser you can check if the phase difference between both
feed lines is 0? degrees or not.

>  I'd then have an RHCP signal for the birds.

If  the vertical driven element is ahead of the horizontal one to get RHCP
the center conductor of the coax cable feeding the vertical driven element
must be connected UP and the braid DOWN while looking the elements standing
behind the reflector the inner conductor of the coax cable feeding the
horizontal driven element must be connected to the RIGHT side and the braid
to LEFT side.
Since you plan to run two identical coax lines from the shack if you add in
the shack a 1/2 electrical wavelenght of coax into the line feeding the
vertical driving element then you get LHCP without changing any coax
connections on top of the dipoles.
The use of folded dipoles with the classic 1/2 wavelength coax balun is
recommended.

> Do I
> _need_ to cut the feedlines to half-wave multiples, or is it just a 
> good idea? I plan on tuning the antennas as dead on to 145.8 as I can, 
> so mismatch will be a minimum at that frequency.

In theory if you cut the feedlines to half-wave multiples you only have the
advantage to exacly measure the impedance of the antenna with an impedance
bridge from the shack without to go on the roof and disconnect cables from
the dipoles.
By the way the VSWR into the line do not change cutting feed lines to
half-wave multiples or any other lenght if the impedance of the antenna do
not match with the impedance of the coax line.
>
> When I don't need RHCP, I can simply use the horizontal feedline for 
> SSB work and the vertical feedline for FM work, setting the coax tee 
> nonsense aside.

It is correct

>  (as a note, the two sets of elements would be tuned identically, 
> centered for minimum swr on 145.8,

It is good

>  but in my experience
> operation across the band is no problem).
>
Agree

> A good coax relay costs about 60-80 dollars and requires associated 
> mounting hardware and weatherproofing, this only adds another $15 for 
> 30 more feet of LMR240.

Since your need is satellite and tropo your project sound to be good and
simple.
>
> Anybody care to share thoughts on this?
>
> 73 and merry christmas
> matt kc4ylv
>
73" and merry cristmas from

i8CVS Domenico

------------------------------

Message: 3
Date: Tue, 25 Dec 2007 18:09:39 -0600
From: Dave Matthews <dave at lostfrogs.com>
Subject: [amsat-bb]  Yaesu FT-897 and HRD satellite tracking problem
To: amsat-bb at amsat.org
Message-ID: <47719BC3.80609 at lostfrogs.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

Merry Christmas everyone. And apologies since I expect the question I ask
here is old hat, but I've researched everywhere and still can't find a
solution that works:

When using the Ham Radio Deluxe satellite tool for satellite tracking with
automatic Doppler shift adjustment, I have a periodic 'polling?'
noise issue with my Yaesu FT-897, the same as I had last field day with HRD
and a FT-857. There is a periodic noise burst that coincides with the black
square animation on the upper left of the satellite tracking tool screen.
This noise burst makes it impossible to listen to very faint signals, and is
annoying as all get out when waiting for a satellite to come into range. FM
and SSB modes. I want to use the HRD program with its built in Doppler shift
tracking, but it is unusable -for me- as a result of this problem.

During Field Day the FT-857 rig was controlled by a laptop, and yagis were
about 20' away pointing at the sky. This current FT-897 setup is on a
desktop style office computer into eggbeaters warming the clouds.

My CT-62 interface cable is shielded, but the shield was not connected!
I tied the shield to ground, no difference. The RS-232 extension cable used
is also shielded. Grounds are good in this upstairs office shack but I am
about 12' above the ground rod. Trying different grounding makes no
difference. Ferrite Beads on the comm cable, looped multiple times through
the beads, etc. makes absolutely no difference. And I just tried a USB to
serial interface replacing the RS-232 from the computer, no difference. So
I've shielded and beaded and grounded and experimented to no avail.

This is a really annoying problem, and I feel there must be something
elementary that I am missing either in the FT-897 setup or in HRD. I expect
it is a Yaesu FT-897/857 problem, but again it may just be a setup issue.

Any response is appreciated,
Dave KI4PSR

------------------------------

Message: 4
Date: Wed, 26 Dec 2007 15:44:28 +0000
From: John Ronan <jronan at irishsystems.com>
Subject: [amsat-bb]  Ande.
To: AMSAT-BB BB <amsat-bb at amsat.org>
Message-ID: <54CED6C4-364E-44C6-8876-B92B145DF982 at irishsystems.com>
Content-Type: text/plain; charset=US-ASCII; format=flowed

Has it's fate been ascertained?

Regards
de John
EI7IG

------------------------------

Message: 5
Date: Wed, 26 Dec 2007 19:14:55 +0100
From: "Simon Brown \(HB9DRV\)" <simon at hb9drv.ch>
Subject: [amsat-bb] Re: Yaesu FT-897 and HRD satellite tracking
	problem
To: "Dave Matthews" <dave at lostfrogs.com>, <amsat-bb at amsat.org>
Message-ID: <002001c847eb$37d34b20$a400a8c0 at hairycreatures>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
	reply-type=original

Sounds like radiation from the CT-62 cable - try putting a ferrite or two on
the cable.

Simon Brown, HB9DRV

----- Original Message -----
From: "Dave Matthews" <dave at lostfrogs.com>

> I have a periodic 'polling?' noise issue with my Yaesu FT-897

------------------------------

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