The distinction between AO91/92's uplink doppler and SO-50 was exactly what I was looking for. Thank you for having the information I was specifically looking for! 73 from KE2CDK
Excellent video. I've been trying to work SO-50 for a few nights now without success. I finally heard some QSL tonight, so that was exciting. Need to reprogram my radio now that I understand how the shift works. Thank you!
Keith, I can't run fast enough to keep up with the satellites LOL I might try moon bounce or something, even ISS, but no.............to busy! Nice video and straight to the point.
You do know that you got the Doppler Shift shifting backwards. For the case when the relative motion is towards each other: [1] A ground receiver of a satellite transmission will receive a high shifted frequency and thus the ground station tunes up. [2] A satellite receiver of a ground transmission will receive a high shifted frequency and since the satellite receiver does not tune up, the ground station tunes it transmitter down so that the higher shifted frequency matches the desired satellite's tuned frequency. Also, the sign of the correction flips (i.e. tune up ->down & down->up) when the relative motion is away from each other.
Yup, he's got it backwards. I think a lot of folks get confused by the terms UL and DL. The repeater on the satellite is not going to change the UL or DL frequencies to suit us mere Earthbound mortals. Therefore, we have to LOWER the UL frequency (our transmit) as the satellite moves toward us and RAISE it when it moves away from us. We must also compensate for the increased DL frequency on approach (by RAISING our receive frequency) and LOWER it as the satellite retreats. It doesn't matter WHAT frequencies are used since the shifts are relative but...shifts increase as frequencies increase. For example...lets pretend the satellite listens on 100 (the UL) and transmits on 400 (the DL). As it approaches me, I listen on 401 but transmit on 99. When it's overhead, I listen on 400 and transmit on 100. Once it passes overhead and begins retreating, I listen on 399 and transmit on 101.
Hello, I really enjoyed your informative video. But I was alarmed to see you used Yeasu FT-65’s as an example of using two separate radios to transmit and receive signals from LEO satellites. The reason for the alarm is I had just purchased one FT-65 due to a specific feature not many are aware of. It’s called VFO Split Mode. Page 7 in the Advanced Manual. It lets you transmit on VFO A and receive on VFO B. And as needed it seems like you can switch VFO’s to change frequencies to offset Doppler shift. This may be a new feature Yeasu added, don’t know. Or perhaps you have tried this feature and had issues. Or if you just didn’t know it’s ok. Just hoping I didn’t get the wrong radio. Regards and much respect.
What’s best antennas to start on satellites? Looked at the egg beaters Martin lynch selling, not sure how good they are, have ICOM 9100 radio, the beams for tracking stats look complicated as in software. Enjoyed your utube film. Mike M1KEY
@@michaelm1keyhardy865 thanks for the feedback. The egg beaters are fine, bit pricey but fine for a put up and go solution. The ideal setup is an ez/az rotator and a 70cm plus 2m beams. This is where you start to spend even more cash!!!
I understand the Dopler Shift but not sure how I set up my radio to adjust for the shift. do I enter a bunch of frequencies and shift up or down to go to different preset frequencies as the space station passes?
Ron, if you are not using a radio which tracks the doppler shift then yes. Put the frequencies of the UHF shift and as the pass procedures change channel.
Good question but no. The main reason is that just like a VHF 2m repeater it needs a large cavity/duplexer to prevent interference from the TX into the RX. This would make the repeater heavy and large. Remember when you are putting stuff into orbit the more it weighs the more it costs to launch it. This is one reason why nano cube sats are being launched more.
The distinction between AO91/92's uplink doppler and SO-50 was exactly what I was looking for. Thank you for having the information I was specifically looking for!
73 from KE2CDK
Excellent video. I've been trying to work SO-50 for a few nights now without success. I finally heard some QSL tonight, so that was exciting. Need to reprogram my radio now that I understand how the shift works. Thank you!
Awesome William, hope to catch you on the birds, Keith
Good video, have you come across a good video or diagram that shows the splitter, cables,type of headphones etc needed
It depends on what you want to split?
Keith, I can't run fast enough to keep up with the satellites LOL I might try moon bounce or something, even ISS, but no.............to busy! Nice video and straight to the point.
Cheers Bob, it's all good fun.
Another very handy video, thanks Keith 👌
Cheers Ray, glad you liked it. 73
Great video! Thank you for sharing your knowledge.
Cheers Bret, best 73. Keith
Nice video. Very useful for me. Thank you.
Awesome, glad it was of use Ashley. Keith
Thank You
Concise & informative as always - many thanks Keith. 73 Ash M7CCQ
Cheers Ash.
Excellent video thank you SeanZS5X
Thanks for the kind feedback Sean.
Nice overview 👍👏👏
Cheers Mark.
You do know that you got the Doppler Shift shifting backwards. For the case when the relative motion is towards each other: [1] A ground receiver of a satellite transmission will receive a high shifted frequency and thus the ground station tunes up. [2] A satellite receiver of a ground transmission will receive a high shifted frequency and since the satellite receiver does not tune up, the ground station tunes it transmitter down so that the higher shifted frequency matches the desired satellite's tuned frequency. Also, the sign of the correction flips (i.e. tune up ->down & down->up) when the relative motion is away from each other.
Yup, he's got it backwards. I think a lot of folks get confused by the terms UL and DL. The repeater on the satellite is not going to change the UL or DL frequencies to suit us mere Earthbound mortals. Therefore, we have to LOWER the UL frequency (our transmit) as the satellite moves toward us and RAISE it when it moves away from us. We must also compensate for the increased DL frequency on approach (by RAISING our receive frequency) and LOWER it as the satellite retreats. It doesn't matter WHAT frequencies are used since the shifts are relative but...shifts increase as frequencies increase. For example...lets pretend the satellite listens on 100 (the UL) and transmits on 400 (the DL). As it approaches me, I listen on 401 but transmit on 99. When it's overhead, I listen on 400 and transmit on 100. Once it passes overhead and begins retreating, I listen on 399 and transmit on 101.
Hello, I really enjoyed your informative video. But I was alarmed to see you used Yeasu FT-65’s as an example of using two separate radios to transmit and receive signals from LEO satellites. The reason for the alarm is I had just purchased one FT-65 due to a specific feature not many are aware of. It’s called VFO Split Mode. Page 7 in the Advanced Manual. It lets you transmit on VFO A and receive on VFO B. And as needed it seems like you can switch VFO’s to change frequencies to offset Doppler shift. This may be a new feature Yeasu added, don’t know. Or perhaps you have tried this feature and had issues. Or if you just didn’t know it’s ok. Just hoping I didn’t get the wrong radio.
Regards and much respect.
@@tomleddy7620 i used the ft-65s as it was the first picture 8found.
What’s best antennas to start on satellites? Looked at the egg beaters Martin lynch selling, not sure how good they are, have ICOM 9100 radio, the beams for tracking stats look complicated as in software. Enjoyed your utube film. Mike M1KEY
@@michaelm1keyhardy865 thanks for the feedback. The egg beaters are fine, bit pricey but fine for a put up and go solution. The ideal setup is an ez/az rotator and a 70cm plus 2m beams. This is where you start to spend even more cash!!!
I understand the Dopler Shift but not sure how I set up my radio to adjust for the shift. do I enter a bunch of frequencies and shift up or down to go to different preset frequencies as the space station passes?
Ron, if you are not using a radio which tracks the doppler shift then yes. Put the frequencies of the UHF shift and as the pass procedures change channel.
Well done. Are there any 2M up and 2M down sats right now?
Good question but no. The main reason is that just like a VHF 2m repeater it needs a large cavity/duplexer to prevent interference from the TX into the RX. This would make the repeater heavy and large. Remember when you are putting stuff into orbit the more it weighs the more it costs to launch it. This is one reason why nano cube sats are being launched more.
Man I suck at working satellites
Nate, don't give up.
Hi Nate, just wondering if your luck has changed?
73
Im tired of the gambling ads on youtube. I dont want to gamble...
❤ HJ5RGG