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Re: Canberra 2.4 GHz opportunity

Hello Peter!

07 Apr 01 09:17, you wrote to All:

 PK> I had not been following the Conifer discussions all that closely
 PK> until I realised in the last few days that I have some like these, and
 PK> that there are lots more to be had locally.

Seems we're lucky in VK, with the demise of Galaxy pay TV.   Lots of unwanted
MMDS converters waiting to fall into amateur hands. :-)

 PK> a.    Connifer II T5120, the boards are marked 700875A and 700874B,
 PK> what looks like a filter, with push-in slugs is marked [
 PK> DFY22R89C2R35BHD - Ch2 USA ANT S 54 Ch1 ], there isn a crystal marked
 PK> 7.6210, with what I now understand are on an 18dB antenna, and I also

The crystal frequency is identical to what I have.  The LO is 1657 MHz (xtal *
256).  This converter is ideal for ATV, as the 2400 MHz ATV channels fall
around 750-800 MHz on the IF.  All you need is a suitable satellite receiver
(e.g. Pace IRD50 or MSS series).  I'm using my Conifer for ATV (but need some
hams to throw a signal my way :) ).

 PK> have b.    Pacific Monolithics PM3151-1951, that I have not opened
 PK> up,
 PK> on a 24dB antenna.

The Pac Mons use a 1951 MHz LO (I have one on a 15dBi antenna).  Will convert
2400 MHz to 449, so a SSB receiver with a broad Rx range or a modified 70cm
converter could be used with this unit.

 PK> Another Amateur in town, whose business is installing satellite TV
 PK> set-ups, has confirmed that he has lots of these that came off houses
 PK> after the terrestrial 2.4GHz TV service went out of business. He has
 PK> agreed to work with the local AR club to get these into the hands of
 PK> locals.
 PK> He also says that there are other places in Australia where they are
 PK> common, but likely to be coming out of service in the next year, so if
 PK> I or someone else here in Australia can "get these going" and put up a
 PK> local How-To site then there is likely to be quite a bit of 2.4GHz
 PK> receive in VK.

Perhaps this should be passed around nationally, as these converters are very
promising for amateur applications.  Now, if we could also get some cheap Tx on
13cm, this could really open up the band for general working, as well as
satellite and ATV.

 PK> I will gladly take advice on what to do.
 PK> For instance, has anyone put a site up with advice on fixing their
 PK> Conifer or Pacific Monolithics? I realise that I should search the
 PK> AMSAT-BB archive for past postings, and I will do that, too.

I suggest you get in touch with Matt, VK2DAG.  He knows a bit about these
converters (basically, what I know comes from Matt, as well as a bit of
tinkering), and he's played with a few of them.

As a starting point, get yourself a 2400 MHz signal source, make a DC power
injector (bias tee) to power the converters and apply some volts (12-14V seems
to work fine) to the converters.  Hook up a suitable receiver and see what you
can come up with.  My converters both came up within 15 kHz of the correct LO
frequency, and seem to work rather well.

If you replaced the xtal in the Pacific Monolithics converter with a 7.6875 MHz
xtal, you should be able to use a 432 MHz transceiver with it for SSB.  I've
never tried this, but it should work, as it's only a minor change of LO
frequency (from 1951 to 1968 MHz).  I have no idea what the specs for the xtal
would be (load capacitance, etc).

I'd like something with a 24 dBi antenna to try out.

Tony, VK3JED

.. Yet another colourful opinion is unleashed upon the world...
|Fidonet:  Tony Langdon 3:633/284.18
|Internet: tlang@freeway.apana.org.au
| Standard disclaimer: The views of this user are strictly his own.

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