[Date Prev][Date Next][Thread Prev][Thread Next] - [Date Index][Thread Index][Author Index]

Re: RE: Geo Opportunity



Bob,

There are many modules available that can do 10 watts on 2 meters. They are 
class AB and suitable for a transponder output. The efficiencies are not all 
that great. Take a look at:

http://www.rfparts.com/module.html

All of the modules labeled AB should work ok. Some of the class C modules 
can be used as AB by adjusting the bias voltage. The spec sheet mentions 
this in some cases.

Pieter





>From: Bob Bruninga <bruninga@usna.edu>
>To: Pieter Ibelings <sietetrescincoprimo@hotmail.com>
>CC: kgschaffrath@beckman.com, <amsat-bb@AMSAT.Org>
>Subject: Re: [amsat-bb] RE: Geo Opportunity
>Date: Wed, 30 Jul 2003 17:20:27 -0400 (EDT)
>
>On Wed, 30 Jul 2003, Pieter Ibelings wrote:
>
> > Why do you want to use a linear cable TV amplifier? I have never seen a
> > cable TV amplifier that can do more than 1 watt or so.
>
>Oh.  I was hoping they were higher power up to say 4 or 5 watts. :-(
>
> > These hybrids are very linear but are normally run with levels of 0dBm
> > or so per tone. They can handle 132 channels spaced 6 MHz apart with
> > good distortions. The P1 dB is around 28 dBm. Why wouldn't a mitsubishi
> > style module work for this?
>
>Those modules are class C, and not usable for linear transponders.
>
>Anyone else have any ideas for off-the-shelf high linearity in the 10W
>class?
>
>Bob
>
> > >From: Bob Bruninga <bruninga@usna.edu>
> > >To: kgschaffrath@beckman.com
> > >CC: amsat-bb@AMSAT.Org
> > >Subject: Re: [amsat-bb] RE: Geo Opportunity
> > >Date: Wed, 30 Jul 2003 15:54:23 -0400 (EDT)
> > >
> > >On Wed, 30 Jul 2003 kgschaffrath@beckman.com wrote:
> > >
> > > > The downlink dosn't look bad. Actually it looks pretty good.
> > > > especially if we can get about 10dbw for the transponder.
> > > > Its the Up link that would be murder, without any antenna gain
> > > > on the sat you would need lotsa kilowatts on the groundstation
> > > > to get a reasonable return signal.
> > >
> > >But, not on 10 meters as the uplink band.  the 14 dB pathloss advantage
> > >really helps...  For any discussions please, we need to see the full 
>link
> > >budget in any email discussions so we can all see what one is talking
> > >about.  Use this format:
> > >
> > >Uplink 10m
> > >TX power         25W    43 dBm
> > >TX Antenna Gain          3 dBi
> > >Polarization loss       -3 dB
> > >Resulting EIRP          43 dBm
> > >
> > >Path Loss at 10m      -153 dBm
> > >Receiver Antenna Gain    0 dBi
> > >Received signal       -110 dBm
> > >Required for 10dB SNR
> > >   in 3 KHz bandwidth  -119 dBm
> > >------------------------------
> > >Margin                  +9 dB
> > >
> > >Downlink 2m
> > >TX power         5W     34 dBm
> > >TX Antenna Gain          3 dBi
> > >Polarization loss       -3 dB
> > >Resulting EIRP          34 dBm
> > >
> > >Path Loss at 70cm     -167 dBm
> > >Receiver Antenna Gain   15 dBi
> > >Received signal       -118 dBm
> > >Required for 10dB SNR
> > >   in 3 KHz bandwidth  -120 dBm
> > >------------------------------
> > >Margin                  +2 dB
> > >
> > >But we still need someone to identify an off-the-shelf
> > >ultra-linear Cable TV AMplifier usable at 2 Meters.
> > >And how much power is available from them?
> > >
> > >Bob, WB4APR
> > >
> > >
> > >----
> > >Sent via amsat-bb@amsat.org. Opinions expressed are those of the 
>author.
> > >Not an AMSAT member? Join now to support the amateur satellite program!
> > >To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org
> >
> > _________________________________________________________________
> > MSN 8 with e-mail virus protection service: 2 months FREE*
> > http://join.msn.com/?page=features/virus
> >
>
>de WB4APR@amsat.org, Bob
>
>PCsat WEB  page     http://www.ew.usna.edu/~bruninga/pcsat.html
>ISS-APRS FAQ:       http://www.ew.usna.edu/~bruninga/iss-faq.html
>CUBESAT Designs     http://www.ew.usna.edu/~bruninga/cubesat.html
>APRS LIVE pages     http://www.ew.usna.edu/~bruninga/aprs.html
>APRS SATELLITES     http://www.ew.usna.edu/~bruninga/astars.html
>MIM/Mic-E/Mic-Lite  http://ssdl.stanford.edu/mims/
>

_________________________________________________________________
The new MSN 8: advanced junk mail protection and 2 months FREE* 
http://join.msn.com/?page=features/junkmail

----
Sent via amsat-bb@amsat.org. Opinions expressed are those of the author.
Not an AMSAT member? Join now to support the amateur satellite program!
To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org



AMSAT Top AMSAT Home