EO-80 FM Transponder Tested (noise floor?)
I notice 2M has a high noise floor when im working AO-7, Theres a few same spots on the passband that have these giant swooshing sounds/etc, It wont be a problem on EO-80 as I as well have found it dosent affect me on FM, maybe EO-79. Looks like we wont have to wait for FOX-1 in september to cover for SO-50... Its really hard to do portable FM operations here where I live, theres lots of trees, so it makes working SO-50 very difficult because of its 250 mw power, I wish they would just increase the power on the thing.
73 KE8AKW
The noise peaks on AO-7 are actually coming through the transponder, not local interference. I don't know if they've always been there or not, but often the noise peaks are stronger than any of the signals in the passband.
As far as SO-50, the transmitter running at just 250 mW is probably part of the reason why the batteries have lasted 13.5 years. AO-27 could only operate the FM transmitter for short periods during it's orbit and AO-51's batteries lasted only 7 years.
Keep in mind that you'll be able to hear EO-80 and Fox-1 much better through the trees, but now your uplink signal will be impacted more by the trees. One medium deciduous tree attenuates signals on 70cm by up to 10.5 dB.
SO-50 is lots of fun, but it can be frustrating because so many people just can't hear it and continue to transmit anyway. I hope lots of the problems we see day-to-day using SO-50 will be reduced by the stronger signals of EO-80 and the Fox-1 series. One minor thing is that tuning the uplink will be a bit trickier than tuning the downlink for stations that are running half duplex. They'll have to remember to tune the transmit frequency up 5 kHz about 4 times during the pass.
Anyone who wants to program memories for EO-80 should follow this plan:
EO-80 AOS - TX 435.070 MHz 210.7 Hz CTCSS, RX 145.840 MHz EO-80 2 - TX 435.075 MHz 210.7 Hz CTCSS, RX 145.840 MHz EO-80 TCA - TX 435.080 MHz 210.7 Hz CTCSS, RX 145.840 MHz EO-80 4 - TX 435.085 MHz 210.7 Hz CTCSS, RX 145.840 MHz EO-80 LOS - TX 435.090 MHz 210.7 Hz CTCSS, RX 145.840 MHz
73,
Paul, N8HM
On Wed, Jun 17, 2015 at 12:42 PM, Nicholas Mahr nicholasmahr1@gmail.com wrote:
I notice 2M has a high noise floor when im working AO-7, Theres a few same spots on the passband that have these giant swooshing sounds/etc, It wont be a problem on EO-80 as I as well have found it dosent affect me on FM, maybe EO-79. Looks like we wont have to wait for FOX-1 in september to cover for SO-50... Its really hard to do portable FM operations here where I live, theres lots of trees, so it makes working SO-50 very difficult because of its 250 mw power, I wish they would just increase the power on the thing.
73 KE8AKW _______________________________________________ Sent via AMSAT-BB@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
I have a doubt...
A few days ago Paul put a list of the proposed channel for EO-80..
I have noted that the TX freqs are from lower to higher (AOS to LOS), is that correct?
From the sat point of view a Tx on the center freq will appears as shifted up at the AOS because the two point are getting closer (doppler is summing), in fact no matter is the freq is for TX or RX if at AOS the shift must be + not -
I'm right?
PS: with the 2.5 Khz of the new Chinese radios the 2m downlink can be shifted to +2.5 Khz at AOS and -2.5 Khz at LOS to improve reception quality
El 17/06/15 a las 12:59, Paul Stoetzer escibió:
Anyone who wants to program memories for EO-80 should follow this plan:
EO-80 AOS - TX 435.070 MHz 210.7 Hz CTCSS, RX 145.840 MHz EO-80 2 - TX 435.075 MHz 210.7 Hz CTCSS, RX 145.840 MHz EO-80 TCA - TX 435.080 MHz 210.7 Hz CTCSS, RX 145.840 MHz EO-80 4 - TX 435.085 MHz 210.7 Hz CTCSS, RX 145.840 MHz EO-80 LOS - TX 435.090 MHz 210.7 Hz CTCSS, RX 145.840 MHz
Yes, Pavel, but since the frequency heard by the satellite as it approaches is higher than what you sent, you need to send at a lower frequency to compensate. The idea is that you want the frequency heard at the satellite to be constant.
As the satellite passes the midpoint, and recedes from view, the frequency it hears is lower than what you transmitted. So you need to send at a higher frequency to compensate, again so that the satellite hears a constant signal.
So, during the pass your transmitter needs to go from lower to higher.
The physics works the same for your reception (it better!), but since the satellite isn't changing its frequency to be constant at your end, you need to move from higher (on approach) to lower (towards LOS) to conpensate.
Greg KO6TH
Pavel Milanes Costa wrote:
I have a doubt...
A few days ago Paul put a list of the proposed channel for EO-80..
I have noted that the TX freqs are from lower to higher (AOS to LOS), is that correct?
From the sat point of view a Tx on the center freq will appears as shifted up at the AOS because the two point are getting closer (doppler is summing), in fact no matter is the freq is for TX or RX if at AOS the shift must be + not -
I'm right?
PS: with the 2.5 Khz of the new Chinese radios the 2m downlink can be shifted to +2.5 Khz at AOS and -2.5 Khz at LOS to improve reception quality
El 17/06/15 a las 12:59, Paul Stoetzer escibió:
Anyone who wants to program memories for EO-80 should follow this plan:
EO-80 AOS - TX 435.070 MHz 210.7 Hz CTCSS, RX 145.840 MHz EO-80 2 - TX 435.075 MHz 210.7 Hz CTCSS, RX 145.840 MHz EO-80 TCA - TX 435.080 MHz 210.7 Hz CTCSS, RX 145.840 MHz EO-80 4 - TX 435.085 MHz 210.7 Hz CTCSS, RX 145.840 MHz EO-80 LOS - TX 435.090 MHz 210.7 Hz CTCSS, RX 145.840 MHz
Sent via AMSAT-BB@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
Ha ha!
Thanks for the explanation... I see i was wrong.
Now i can program my radios in the correct way.
73 and thanks.
El 21/06/15 a las 21:56, Greg D escibió:
Yes, Pavel, but since the frequency heard by the satellite as it approaches is higher than what you sent, you need to send at a lower frequency to compensate. The idea is that you want the frequency heard at the satellite to be constant.
As the satellite passes the midpoint, and recedes from view, the frequency it hears is lower than what you transmitted. So you need to send at a higher frequency to compensate, again so that the satellite hears a constant signal.
So, during the pass your transmitter needs to go from lower to higher.
The physics works the same for your reception (it better!), but since the satellite isn't changing its frequency to be constant at your end, you need to move from higher (on approach) to lower (towards LOS) to conpensate.
Greg KO6TH
Pavel Milanes Costa wrote:
I have a doubt...
A few days ago Paul put a list of the proposed channel for EO-80..
I have noted that the TX freqs are from lower to higher (AOS to LOS), is that correct?
From the sat point of view a Tx on the center freq will appears as shifted up at the AOS because the two point are getting closer (doppler is summing), in fact no matter is the freq is for TX or RX if at AOS the shift must be + not -
I'm right?
PS: with the 2.5 Khz of the new Chinese radios the 2m downlink can be shifted to +2.5 Khz at AOS and -2.5 Khz at LOS to improve reception quality
El 17/06/15 a las 12:59, Paul Stoetzer escibió:
Anyone who wants to program memories for EO-80 should follow this plan:
EO-80 AOS - TX 435.070 MHz 210.7 Hz CTCSS, RX 145.840 MHz EO-80 2 - TX 435.075 MHz 210.7 Hz CTCSS, RX 145.840 MHz EO-80 TCA - TX 435.080 MHz 210.7 Hz CTCSS, RX 145.840 MHz EO-80 4 - TX 435.085 MHz 210.7 Hz CTCSS, RX 145.840 MHz EO-80 LOS - TX 435.090 MHz 210.7 Hz CTCSS, RX 145.840 MHz
Sent via AMSAT-BB@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
participants (4)
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Greg D -
Nicholas Mahr -
Paul Stoetzer -
Pavel Milanes Costa