Contact thru ISS

[RichardKramer]

Made a contact this am thru ISS uplink 145.990, downlink 437.795 (doppler effect); to KB3IAI in Gambrills, MD - Grid FM19. I'm using an FT8900 / 50w into a Comet GP-15 about 35' agl in Grid FN20. My first confirmed contact.

Rich - N3VMY

 

[wyShack]

Back down on the Power -I believe most are using 5 W and small beams but the guidelines is 50 watts based on a 0dbi antenna. Tooo much pwoer causes the 'bird' to back down both rx and tx. This is based on the FM sats -the ISS is a bit different but still no reason to use more powr than you have to. The station is only running 10 Watts so that should be plenty.

 

[RichardKramer]

Back down on the Power -I believe most are using 5 W and small beams but the guidelines is 50 watts based on a 0dbi antenna. Tooo much pwoer causes the 'bird' to back down both rx and tx. This is based on the FM sats -the ISS is a bit different but still no reason to use more powr than you have to. The station is only running 10 Watts so that should be plenty.

The first pass I made contact with ISS it was to my South; area 4 stations coming in L/C hence the higher pwr I used; the other pass ISS was well North of me, area 1 stations L/C hence the higher power used. When ISS was almost overhead I dropped the pwr to 20w and was not heard. With my omni-directional signal, I'm sure a guy with a 4 element beam with a 5w ht is going to outdo me reaching ISS.

 

[wyShack]

The first pass I made contact with ISS it was to my South; area 4 stations coming in L/C hence the higher pwr I used; the other pass ISS was well North of me, area 1 stations L/C hence the higher power used. When ISS was almost overhead I dropped the pwr to 20w and was not heard. With my omni-directional signal, I'm sure a guy with a 4 element beam with a 5w ht is going to outdo me reaching ISS.

Remember your vertical is 'pointed' toward the horizon -so you should work the ISS when it is fairly low to the horizon. At that point, you have a bit of 'gain' so 20 watts is good. above about 45 degrees you won't have enough power even at 50 watts-it is not distace but where in your antenna pattern the ISS is. BTY there are a couple of antennas that you can build that will give you a better shot (Moxen or turnstile) Have fun 73.

 

[RichardKramer]

Remember your vertical is 'pointed' toward the horizon -so you should work the ISS when it is fairly low to the horizon. At that point, you have a bit of 'gain' so 20 watts is good. above about 45 degrees you won't have enough power even at 50 watts-it is not distace but where in your antenna pattern the ISS is. BTY there are a couple of antennas that you can build that will give you a better shot (Moxen or turnstile) Have fun 73.

Thanks for the info; have a Happy 4th!