Hi Andy,
Because you have 1 MHz between two signals, then you can try to do something yourself. HAM radio is an experiment ;).
If I would be you I will try to make two quarter-wave impedance transformers using a cable, as the frequency trap. As a consequence, you can reach a different ratio between both signals on 144 and 145 MHz. Sorry for my not professional/technical English words in this case. I hope people who know technical English better than me and catch my idea can write to you more (some keywords).
Another similar solution is the notch filter from cable, eg. http://dl4xav.sysve.de/coax.filter/coax-filter.html
Here is another solution https://www.pa0nhc.nl/IMDfilter/EN/CableNotchFilter145MHz/KabelNotchFilterV1...
If the trap/notch filter will be too wide (wider than 1MHz), then you can try to move the maximum of the resonance/attenuation much more outside both frequencies 144 and 145 and you can try to operate on the slope.
73, Armand SP3QFE
W dniu 2020-12-28 19:29, Andy Brian napisał(a):
Thanks all for good suggestions. I Will try all to find a good results. I start searching for solutions because I saw so many good received from SSTV pictures from ISS this days. APRS frequency here is on 144.800MHz
BR Andy
On Mon, Dec 28, 2020 at 7:15 PM Pedro Converso [email protected] wrote:
Try attenuate RF entry level on SDR Dongle
73, lu7abf, Pedro
On 12/28/20, Jean Marc Momple [email protected] wrote:
Andy,
To filter at RF level between 145.800 and 145.825 MHz will require
a lot of
cavities and even if possible most probably the attenuation would
make the
whole exercise useless.
May be at baseband level but I am not really competent to advise,
your
question is of interest and anyone who may help there is most
welcome.
73
Jean Marc (3B8DU)
On Dec 28, 2020, at 9:34 PM, Andy Brian [email protected]
wrote:
Hi,
I received many pictures from ISS. I'm using RTL dongle 2832 with
SDR#
program and MMSSTV with virtual cable and Orbitron.I found many rainbow lines
on
pictures and I analysed that this is the case of transmission
with APRS
local stations around 5km away and 1mhz below my receiving. Anyone have experirence of good filtering or set the SDR# program
to
reduce the infulence from of transmitter which is far away from 145.8MHz but still in the
2MHz
bandwidth of RTL2832?
BR Andy
Sent via AMSAT-BB(a)amsat.org [1]. 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!
View archives of this mailing list at https://mailman.amsat.org/hyperkitty/list/[email protected] To unsubscribe send an email to amsat-bb-leave(a)amsat.org [1] Manage all of your AMSAT-NA mailing list preferences at https://mailman.amsat.org
Sent via AMSAT-BB(a)amsat.org [1]. 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!
View archives of this mailing list at https://mailman.amsat.org/hyperkitty/list/[email protected] To unsubscribe send an email to amsat-bb-leave(a)amsat.org [1] Manage all of your AMSAT-NA mailing list preferences at https://mailman.amsat.org
Links:
[1] http://amsat.org
Sent via AMSAT-BB(a)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!
View archives of this mailing list at https://mailman.amsat.org/hyperkitty/list/[email protected] To unsubscribe send an email to amsat-bb-leave(a)amsat.org Manage all of your AMSAT-NA mailing list preferences at https://mailman.amsat.org