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AO-92 to Camera Mode

Clint Bradford
 

From AMSAT-NA ...

The command team has had a few requests for camera mode on AO-92 over the
last few weeks, and it's been a while, so let's take some pictures next
week.


Next Tuesday morning, April 28th, we'll attempt to command the camera on at
approximately 1440Z and 1612Z. We'll also try the 1750Z pass. If we can't
command on the 1750Z pass, we'll find a suitable pass later in the week for
the west coast.



Take a look at
https://www.amsat.org/foxtelem-software-for-windows-mac-linux/ for a guide
on how to set up FoxTelem, and https://www.amsat.org/tlm/showImages.php?id=4
for near-live images as we go. Remember, the more stations submitting
telemetry during the event, the better the chance of complete images!



73, Drew KO4MA
AMSAT VP Operations

Brad Smith
 

I guess I am a little confused. Can one receive the pics with an iPhone and a radio, like the SSTV images from the ROISS, or does one need a permanent station with a computer? 

Brad KC9UQR

Sent from Brad’s iPad

On Apr 26, 2020, at 12:15 PM, Clint Bradford via groups.io <clintbradford@...> wrote:

From AMSAT-NA ...

The command team has had a few requests for camera mode on AO-92 over the
last few weeks, and it's been a while, so let's take some pictures next
week.


Next Tuesday morning, April 28th, we'll attempt to command the camera on at
approximately 1440Z and 1612Z. We'll also try the 1750Z pass. If we can't
command on the 1750Z pass, we'll find a suitable pass later in the week for
the west coast.



Take a look at
https://www.amsat.org/foxtelem-software-for-windows-mac-linux/ for a guide
on how to set up FoxTelem, and https://www.amsat.org/tlm/showImages.php?id=4
for near-live images as we go. Remember, the more stations submitting
telemetry during the event, the better the chance of complete images!



73, Drew KO4MA
AMSAT VP Operations

Robert Switzer
 

That link doesn't really say how to set up for Image mode...  can I assume slow speed DUV mode?

Clint Bradford
 

From https://www.amsat.org/foxtelem-software-for-windows-mac-linux/  ---

Fox-1 satellites include two telemetry formats:

  • Slow Speed, also called Data Under Voice (DUV) is 200 bps FSK data sent at the same time as the transponder audio. Whenever the transmitter is on, data is being sent. This happens during beacons and during live QSOs.
  • High Speed is 9600 bps FSK sent instead of the transponder. This is used for data intensive experiments such as the Virginia Tech Camera and the University of Iowa HERCI experiment. This is only active when commanded from the ground. You can recognize High Speed because it sounds like an old school computer modem.
  • FoxTelem will receive and store both formats assuming you can feed it audio that does not have the frequencies below 200 Hz filtered.  For High Speed, the audio must also extend to include the full 9600bps bandwidth of the FM signal.  For both modes this is best achieved from a Software Defined Radio or from the 9600 bps packet port of some radios.  See the user guide for more details.

 

This is a digital signal and not the same as SSTV that can just be done over a regular, FM receiver. The signal is sent over FM, but it utilizes the full audio spectrum including frequencies below 200 Hz that are often filtered out of the audio. You likely will be missing some of the signal if you try to capture it over a standard FM receiver. Your best bet is to use some kind of SDR. I've used the cheap RTL SDR dongles that can be purchased from Amazon for about $20 with great success. You can use a regular computer or an Android device with appropriate USB On-The-Go cable adapter to connect to the SDR. iPhone can't be use because iOS does not allow sufficient access to the USB hardware to use such a device.

To decode the pictures and upload them, you will need to set up the free Foxtelem program from AMSAT. You can either record the data with your SDR and software like SDR Sharp or SDRTouch during the pass and play back later or live stream the unfiltered audio out to Foxtelem during the pass.

Note, AO-91 and AO-92 both are always transmitting a low-bitrate DUV signal using this same technique along with the regular FM audio so you can test this out during any pass. What's unique tomorrow is that they are turning on the camera and sending high-resolution pictures down using the full audio channel for data instead of voice. The low-bitrate Digital-Under-Voice signal only sends back lower-resolution sensor telemetry, but it's still fun to pick up.

-Loren
K7IW


On Mon, Apr 27, 2020 at 6:45 AM Brad Smith via groups.io <corlissbs=aol.com@groups.io> wrote:
I guess I am a little confused. Can one receive the pics with an iPhone and a radio, like the SSTV images from the ROISS, or does one need a permanent station with a computer? 

Brad KC9UQR

Sent from Brad’s iPad

On Apr 26, 2020, at 12:15 PM, Clint Bradford via groups.io <clintbradford=mac.com@groups.io> wrote:

From AMSAT-NA ...

The command team has had a few requests for camera mode on AO-92 over the
last few weeks, and it's been a while, so let's take some pictures next
week.


Next Tuesday morning, April 28th, we'll attempt to command the camera on at
approximately 1440Z and 1612Z. We'll also try the 1750Z pass. If we can't
command on the 1750Z pass, we'll find a suitable pass later in the week for
the west coast.



Take a look at
https://www.amsat.org/foxtelem-software-for-windows-mac-linux/ for a guide
on how to set up FoxTelem, and https://www.amsat.org/tlm/showImages.php?id=4
for near-live images as we go. Remember, the more stations submitting
telemetry during the event, the better the chance of complete images!



73, Drew KO4MA
AMSAT VP Operations

Clint Bradford
 

I have been partial to NooElec products (great, informative Web site, lots of support).

https://www.nooelec.com/store/

Loren - Which Amazon product/vendor have you had good luck with?

Clint




On Mon, Apr 27, 2020 at 01:16 PM, Loren Lang wrote:
Your best bet is to use some kind of SDR. I've used the cheap RTL SDR dongles that can be purchased from Amazon ...

Clint Bradford
 

I have been partial to NooElec products (great, informative Web site, lots of support).

https://www.nooelec.com/store/

Loren - Which Amazon product/vendor have you had good luck with?

Clint




On Mon, Apr 27, 2020 at 01:16 PM, Loren Lang wrote:
Your best bet is to use some kind of SDR. I've used the cheap RTL SDR dongles that can be purchased from Amazon ...

Clint Bradford
 

Images received this round ...

https://www.amsat.org/tlm/showImages.php?id=4

 

I have been using the RTL-SDR Blog variant with good success. There seem to be some other interesting options now including some that claim to be modified for HF usage or have BiasT. I think I've even found some cheap, clones of the RTL-SDR Blog variant now on Ebay where the fonts look a little off. I might have to review the market options, though, I think the next SDR I buy will probably be focus on 1.7 GHz for use with collecting NOAA high-resolution satellite imagery. I'm not sure if my HackRF is up to the task.

- Loren
K7IW