[amsat-bb] Receiving with an rtl-sdr, desense on transmit

[Patrick STODDARD (WD9EWK/VA7EWK)]

​Hi Phil!

I work satellites with an SDR receiver sitting alongside
my transmit radio (FT-817ND, or an HT or dual-band FM mobile
for FM satellites), and I don't have issues with receiving
while transmitting. I started with a FUNcube Dongle Pro+,
have used an SDRplay RSP1 for almost 2 years, and in recent
weeks started using an SDRplay RSP2. I use an Elk 2m/70cm
log periodic antenna, and there is a 2m/70cm diplexer between
the antenna and my radio setup (log periodic has only one
coax feedpoint). The diplexer is also serving as a bandpass
filter, adding some protection to the SDR receiver along with
the bandpass filters in these SDR receivers. I use an MFJ
MFJ-916B diplexer - inexpensive, and does at least as well as
the more expensive Comet and Diamond equivalents.

I have posted a bunch of RF recordings from different passes
worked with an SDR receiver for the downlinks. Most of these
are using an SDRplay RSP1, but you can get the large WAV
file and run it through an SDR program to see how things looked
and sounded from my end. These are in folders at:

http://dropbox.wd9ewk.net/

Look for folders with satellite names in them like AO-73, and
the WAV files all start with HDSDR in the file names within
those folders. Some of those folders will have other recordings,
when I was using something other than an SDR receiver for those
passes, or may have MP3 audio along with the large WAV files
which would have what I heard while working that pass.

73!





Patrick WD9EWK/VA7EWK
http://www.wd9ewk.net/
Twitter: @WD9EWK












On Mon, May 1, 2017 at 12:11 AM, Phil <phil_lor at bigpond.com> wrote:

> On Sun, 30 Apr 2017 18:06:17 -0500
> "Mac A. Cody" <maccody at att.net> wrote:
>
> > I am working on a similar project and started with an RTLSDR device.
> > I have since switched to using an SDRPlay RSP2, due to its better
> > input filter, Digital resolution, and shielding.
>
> I also have an interest in this project. Can you receive on your sdrplay
> rsp2 while you're transmitting without any additional filters?
>
> --
> Regards,
> Phil
> _______________________________________________
> Sent via AMSAT-BB at amsat.org. AMSAT-NA makes this open forum available
> to all interested persons worldwide without requiring membership. Opinions
> expressed
> are solely those of the author, and do not reflect the official views of
> AMSAT-NA.
> Not an AMSAT-NA member? Join now to support the amateur satellite program!
> Subscription settings: http://www.amsat.org/mailman/listinfo/amsat-bb
>