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Re: A 'L Band Pod' Story



Hi Bert:

I purchased a pair of the "Pods",  hoping that the three modules inside the
Pod; RX preamp, L-band driver, and L-band PA, were individual modules,  and
that they could be separated, and used individually.  This is not the case.
All three modules are integrated on a single PCB.

I was very disappointed to find that the quadrafiliar helix was LHC, instead
of RHC.  I had hopped to use the antenna separately for GPS.  You will find
that the antenna connector's center pin is at DC ground, and will have to be
modified with a blocking capacitor if used with a GPS or other receiver that
supplies the DC power on the coax.

I have not been able to locate any documentation at all on the unit.  I
would really like to find a schematic of the unit before I try to power up
the unit.  Do you have connector pin-out info, or any other documentation?

73,

Woody
KJ4SO


----- Original Message -----
From: "Eric A. Cottrell" <eac@shore.net>
To: "AMSAT-BB" <amsat-bb@AMSAT.Org>
Sent: Wednesday, February 21, 2001 20:47 PM
Subject: [amsat-bb] A 'L Band Pod' Story


> Hello,
>
> I know there are a few people on this list that got one of these things.
>I finally decided to hook it up and see if it works.
>
> One of the problems I had using it with GPS is my Garmin 12XL will only
> switch to the external antenna if it senses a current drain on the antenna
> port.  So that did not work.
>
> I brought the pod, a F connector 18 volt power supply (from a Radio shack
> preamp) and other sundry items out to the outdoor test range in the
backyard.
> It appeared that the 50ma wall wart on the 18 volt could not power the
preamp
> but I suspect it was really a loose connection inside the shielded
housing.
>
> I was able to power the preamp and I used my recently purchased VR-5000
whiz
> bang receiver to search for interesting signals.  There seemed to be
several
> signals around 1575 if I put the receiver in sideband.  I also say some
> digital signals on INMARSAT.  I did not see any analog stuff I heard was
> on there.
>
> Researching with the web I realized that the pod is LHC and the analog
> INMARSAT stuff was RHC.  No problem, I will just use my 7-1/2 foot dish.
> I took a loop of wire and managed to hang the pod next to the C/KU feed on
> the dish.   I disconnected one of the LNB feeds and connected it up to the
> pod.  I went inside and hooked up the VR-5000 to my splitter.  My Drake
1824
> was powering the Pod.
>
> INMARSAT AOR-W is near PAS-9 so I moved the dish there and got some weak
> blips on the VR5000's band scope.  They peaked up just east of PAS-9.
>
> I scanned the INMARSAT-A band and picked up a number of stations.  A few
> were almost full quieting but some were alittle noisy.  The scanner is not
> modified for the wider bandwidth so the signals sometimes were distorted.
>
> It appears that something causes the preamp gain to drop off below about
1525
> so some modifications may be needed to get it down into the ham band.
There
> is a diplexer in this unit.
>
> I realized that I was using a omnidirectional antenna for the feed.  I had
the
> pod apart a few months ago and it may pe possible to replace the existing
> antenna that is on a cylinder with a better feed type antenna.
>
> 73 Eric eac@shore.net  WB1HBU
> ----
> Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA.
> To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org
>


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