Hi Zach. About a year ago the battery on AO-73 began to drop in Voltage from its nominal 8.3V at full charge down to 7.8 ish. It's unclear if this is due to a 9 year old battery with reduced capacity, or a hardware fault. - Voltage reference etc etc. Although we have designed in many strategies for dealing with power issues, the one we ideally need in this situation does not exist in the firmware. To prevent the battery discharging to a dangerously low voltage during eclipse, we have enabled a mode where the transmitter is on in sunlight, but when it enters eclipse it changes to  "receive only" .  i.e  The transmitter is off, but the RX is on and telemetry is collected and stored by the processor for use in Whole Orbit Data.

Ideally we need Transponder on in sunlight.....receive only in eclipse.   But that's not an available option.

The transponder can be commanded on, but to avoid further degradation of the power system, we would need to manually command it off before it enters eclipse, or take a big risk. If we're feeling brave, perhaps we can look at some transponder operation over a holiday period and use the opportunity to assess the battery / EPS status. 73 David  G0MRF.    - See you in Dallas (?)

On Monday, 16 October 2023 at 22:05:27 UTC, Zach Metzinger via AMSAT-BB amsat-bb@amsat.org wrote:

On 1/8/22 18:00, Paul Stoetzer wrote:

• With the recent re-enabling of the AO-73 transponder, Paul Stoetzer,

N8HM, has issued the 59th 73 on 73 Award to JA1OJA. This award was completed using CW only. N8HM notes, "AO-73 is a fantastic satellite, but it can be a challenge due to the transponder's frequency drift. With the recent technical issues, we don't know how long it will be available. Get on and make some QSOs so that more operators can receive this award!" More information about the award can be found at https://amsat-uk.org/funcube/73-on-73-award/ https://amsat-uk.org/funcube/73-on-73-award/

Hello Paul,

Any idea if AO-73's transponder will ever be re-enabled?

I've search the -bb and looked at funcube.org.uk. Nothing forthcoming from those outlets.

Was there a hardware failure?

Thanks,

--- Zach N0ZGO

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