Observe the same over India and south east Asia. Maybe some stations from south east Asia can share their observations. 73 Nitin [VU3TYG]

From: PA3GUO pa3guo@upcmail.nl To: amsat-bb amsat-bb@amsat.org Sent: Sunday, 18 December 2016 6:50 PM Subject: [amsat-bb] ISS packet 70cm weak?

Anyone else finds the signals weak ? Uplink as well as downlink? Maybe worse in EU compared to other continents? PA3GUO Henk _______________________________________________ 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

Hi!

If the two Ericsson HTs used on the ISS have the same power output, 70cm signals should be weaker than what we heard on 2m. There would be higher losses in the coax between the radio and antenna, along with a higher path loss, using 70cm. I also notice that how I align my antenna is more important when working the ISS on 437.550 MHz than when it was on 145.825 MHz.

Uplink issues could be similar to what is happening on the ISS. Transmitter power, coax loss, path loss... they all play a part in this.

With all of that said, I am able to deal with having to twist my Elk log periodic more, and also changing frequencies (memory channels in my HTs) to compensate for Doppler on 437.550 MHz. It takes a little more work, but for me it isn't much different than working ISS or the weaker NO-84 digipeater (when active) on 145.825 MHz. I think the shift to 70cm has been harder for the home stations that use vertical antennas, and the radios are not under computer control. Those stations are having a tougher time coping with the operations on 70cm. Based on some comments I have received directly and seen in a few online forums, those using 2m/70cm verticals with gain are really struggling. The radiation patterns of many of those antennas on 70cm just isn't good for working something up in the sky. Some of those antennas (for those in the Americas) are also tuned for 440-450 MHz, and perform poorly below that range.

Not as many gateway stations are listening to 437.550 MHz, but there are a few using stations with computer control that are able to track the ISS as it goes across the sky. That has helped to populate the listing and map on ariss.net, but is not a perfect replacement for the many other stations that are on 145.825 MHz. Regardless of the number of gateways listening on 70cm, I'm still having fun trying different antennas and seeing more stations give ISS packet on 70cm a try.

73!

Patrick WD9EWK/VA7EWK http://www.wd9ewk.net/ Twitter: @WD9EWK

On Sun, Dec 18, 2016 at 1:20 PM, PA3GUO pa3guo@upcmail.nl wrote:

Anyone else finds the signals weak ? Uplink as well as downlink? Maybe worse in EU compared to other continents? PA3GUO Henk