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RE: Dishnetwork Dish





 > -----Original Message-----
 > From: Howie DeFelice [mailto:hdefelice@petrexintl.com]
 > Sent: Thursday, June 08, 2000 5:49 PM
 > To: amsat-bb@AMSAT.Org
 > Subject: RE: [amsat-bb] Dishnetwork Dish
 > 
 > 
 > 
 > 
 > The LNB is a combination low noise amplifier and 
 > downconverter. The LNA 
 > amplifies the 12.2 - 12.7 GHz. DBS freqs. The signal then 
 > enters a mixer 
 > where it is mixed with a L.O. of 11,250 MHz. To produce an 
 > I.F. of 950 to 
 > 1,450 MHz.  However, large numbers of LNB's were manufactured to 
 > accommodate the standard domestic Ku band fixed satellite 
 > service band of 
 > 11.7 GHz. To 12.2 GHz., using a L.O. of 10,750 MHz., to 
 > produce an I.F of 
 > 950 to 1450 MHz. By extending the I.F range to cover a wider 
 > band of 950 to 
 > 2050 MHz., manufacturers could use the same L.O. of 10,750 
 > MHz. For both 
 > the FSS and DBS bands. The L.O. in these devices is the most 
 > expensive part 
 > and are typically stabile to +/- 100 KHz.. The frequency 
 > range mentioned is 
 > the I.F. frequency range. It should also be noted that the 
 > DBS service uses 
 > circular polarization while the FSS service uses orthogonal linear 
 > polarization. I wonder how hard it would be to get into the LNB's to 
 > extract and re-tune the L.O.'s ?
 > 
 > 
 > Howie
 > AB2S
 > 
I don't want to brag but retuning lnb's has been done in uerope for a couple
of years with good result's.

We use lnb's with 2 lo's for this like the grundig aun11s.
When you stik the hi lo (small dro) on the low lo ("large" dro) you can tune
the lo to 9GHz so that 10.400 in means 1.400 out.

it is a job that can be done in half an hour by any ham (some may need a bit
of guidens)

take a look at http://www.qsl.net/pa3gco to read the full story

73 de Andre PE1RDW
aprsdigi co-ordinator Netherlands
member aprs workgroup Netherlands 
mailto:pe1rdw@aprsnl.org

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