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Re: P3D information

on 10/10/00 7:36 PM, Phil Karn at karn@ka9q.net wrote:

>> This is probably true for Amsat-NA.  But Amsat-thirdworld will get lost in
>> the process. 
> Oh yes, members of Amsat-thirdworld are in a much better position to
> put up the multi-kilobuck towers, antenna arrays and rotors and to buy
> all the necessary transceivers and transverters needed to work Mode B
> than anyone in North America.

Excuse me, Phil.  But you are quite mistaken about what's necessary to work
mode B.

First of all, you don't need kilo-buck towers, arrays and rotors.

Let's see what you can do mode B with (this is the setup I have now):

1.) Medium Size TV Rotor - $35 at Dayton
2.) Pass Through Alliance Rotor - Free from another ham who had no need
(these are fairly abundant and cheap)
3.) 20 foot telescoping mast from Radio Shack - $35
4.) Heavy Duty Tri-pod from Radio Shack - $17

The total cost of my setup less the antennas and coax was about $100 by the
time I added all of my hardware, fiberglass boom, etc.  Certainly not

Now, I purposely left out the antennas because I stole them from another ham
for $75.  They are the KLM 22 elements on 2m and 40 elements on 432.
However, many guys homebrew their setups for far less than the cost for new.
So let's say, it costs $400 for a pair of antennas.

That's everything you need minus the transceivers to work mode B for $500.

I don't want to hear it.

Now, I also need to add a transceiver in there.  Let's see I started out
with the Yaesu FT-290 and FT-790 as my satellite rigs.  Worked fine.  Worked
plenty AO-10 on them.  Then I sold those and some other gear and basically
got an FT-847 for free plus some cash.

I don't knowo what transverters you are talking about.  For mode B you
certainly don't need those.  You must be thinking microwaves....

Let's say someone has to buy an FT-847 outright.  OK, so that's $1500.  Now
our total satellite station is up to $2000.  OK, Kilobucks.


That same $1500 needs to be spent on the FT-847 for mode B must be spent for
your digital microwave modes too.  PLUS:

Antennas - OK -- $500 for antennas and masts and hardware.  After all, you
will need some gain to get up to the birds with low power.  So you will have
to have moveable antennas unless you plan on working P3D only at apogee.

So our microwave and mode B setup are now the same cost...


Modifying the FT-847 for wideband digital.  I think this is about $300 or


Let's see, an S band converter from SSB is $459
An L band transverter from DB6NT with 1.5 W out is $424
An S band transverter from DB6NT with 1 W out is $500

Prices start to go up as you add the other bands.

OK, you can homebrew.  Let's see microwave test equipment (needed IMHO) was
rather expensive last time I looked.  If you don't work for a Motorola,
Lucent, Nokia, Agilent or Qualcomm, etc. you'll have difficulty unless you
fork out $$$ for the test equipment.  Sure, there's cheap and easy projects,
but still you have to have some test equipment.

Oh yeah, I forgot, each additional microwave band needs an additional
antenna and pointing device.  With just a watt or less out of the
transverter, I don't think even a digitally modulated signal would make it
with a low gain antenna.  OK, so then you have to add microwave power...that
gets expensive too.

Phil, sad to say it, but you look silly when you claim mode B costs
kilobucks and needs lots of transverters compared to your digital microwave

Microwave modes are neat as well as digital modes.  I'd love to play on S
band or X band with P3D.  But I don't have the $500 to $1000 to drop on that
stuff right now.  Neither do most folks.  Sure, I am thinking of how I could
homebrew some stuff (I have some 23 GHz GUNN diode oscillators designed to
be FM modulated with a 140 MHz IF), but I lack the test equipment (I do have
the skills as I went to school to learn microwave theory).

I hate to say it, but ham radio will likely have to wait for the commercial
world to increase in frequency in order for microwaves to be economical.
That's what has happened at 2.5 GHz and below.  Ten years ago, we would have
killed to be able to buy a 1.9 GHz 1 Watt amplifier for $2.00 and have it in
a plastic package!  The cellular industry and the wireless industry in
general have made this possible.  Hams can benefit now too from lower prices
and our commercial equipment will be cheaper.  Kenwood will be releasing a
new satellite rig with 1.2 GHz built in for the same price as like an
FT-847.  So microwaves are coming, but if you want to play now on them, it
will cost some good money.

Sorry, Phil, please show me how I have to spend kilobucks and have tons of
transverters to operate mode B.



Jon Ogden
NA9D (ex: KE9NA)



"A life lived in fear is a life half lived."

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