Trevor and Bob are correct. Turning the PL back on does NOT eliminate the QRM, it simply hides the source. The QRM is still there, but like Bob put so well, we now have a blindfold on. I understand it may be a little less pleasant to listen to, but at least now you can use your ham skills to overcome it. Transmit when the QRM fades to capture the receiver, transmit during breaks, rotate your arrow or change polarities on the uplink to try to overpower the QRM. These are all the things you can do to make the contact, that would be more difficult or impossible with the PL on. Don't hesitate to step above QRP power levels to get over the illegals...just make sure they are illegal QRM and not simply hams speaking a different language using the satellite.

One of the other issues that drove this decision was watching the QRM we cause each other with the PL on. I have stood and watched portable operators not able to crack the squelch hold the PTT down until they could. A couple of ops spread out across the footprint doing this at similar ERPs and no one gets through. With the PL off at least the considerate operator can hear the logjam and stand down for a moment (because the considerate op uses full duplex ALWAYS). Field Day 2006 is a perfect example of this problem at a maximum.

There will always be some interference that we can not eliminate. This hasn't changed since the UO-14 days really. But there will be some that we can eliminate with some perseverance. Not too long ago a pizza place in the Northeast US was busted and fined for their use of a illegal long range phone in the 2m band. This was on AO-27's uplink. Just a few months ago I convinced a gentleman here for the winter to move his 45 watt Echolink node off 145.900. I heard him operating when attempting to use VO-52, but what if he had been 15-20 khz higher and outside of my range direct? How many passes of AO-51 with the PL would have been wrecked before we found him?

The software upgrades currently in progress on AO-51 may result in some higher downlink levels than we are used to hearing. As this happens the competition and contention on the uplink will also increase, simply because more operators will be able to hear it. We all need to be aware of this, and welcome the new operators by operating as considerately as possibly. This means full duplex, not transmitting unless you can hear the downlink, keeping QSOs brief, and limiting yourself to just a few contacts on a busy pass. Take the ragchews up to the transponders, they will appreciate the use. Give a little leeway for the guys operating from cruise ships, a rare grid, and especially for those doing a hamfest or school demonstration, because you may appreciate the same someday. And finally take a minute to pass your thanks to the guys who keep this satellite going by dedicating their time on a daily basis. Next time you hear Mike KE4AZN, Gould WA4SXM, or Jim WD0E, let them know you appreciate their efforts.

I hope this has helped explain things some. I want everyone to feel free to bring their concerns and inquiries to me whenever possible.

73, Drew KO4MA AMSAT-NA Vice President of Operations AMSAT LM 2332

At 09:21 AM 2/3/2007 +0000, Trevor wrote:

--- Justin Burket zorton@jtan.com wrote:

...

Chalk this e-mail up for another vote to reactivate the PL tone.

But your email shows the reason why we don't want PL tones on ANY satellite.

PL tones don't cure the problem they hide it so we can shut our eyes and pretend it doesn't exist. The satellite is still unavailable for low power users, you have to transmit high power to overcome the interference so the satellite can hear you. PL tones aren't magic cure-alls.

Since AO-51's tones been turned off we've got a far better understanding of what the situation is really like in different parts of the world. Unless we have the inform necessary to understand the problem there is no way we can

even

to begin to start resolving it.

73 Trevor M5AKA

Honestly, what can be done? Without a serious policing by governments of the offenders nothing will relieve the situation. Too often graft in government bureaucracies subvert any reform or implementation of laws. We have the same problem with fisherman buying 2m FM radios for their "secret band". Of course unlicensed, but used in remote areas beyond the range of limited FCC monitoring. Hams reporting and witnessing has been the most effective deterent up here.

73's, Ed - KL7UW ========================================= BP40iq, Nikiski, AK http://www.qsl.net/al7eb Amsat #3212 Modes: V - U - L - S USA Rep. for Dubus Magazine: dubususa@hotmail.com =========================================

At 09:01 PM 2/3/2007, Edward R. Cole wrote:

Honestly, what can be done? Without a serious policing by governments of the offenders nothing will relieve the situation. Too often graft in government bureaucracies subvert any reform or implementation of laws. We have the same problem with fisherman buying 2m FM radios for their "secret band". Of course unlicensed, but used in remote areas beyond the range of limited FCC monitoring. Hams reporting and witnessing has been the most effective deterent up here.

Well here, probably nothing can be done, since the source of the QRM is foreign, and Indonesia is a country made up of 5000 islands and well over 100 million people. Enforcement would be difficult, and I suspect they have bigger fish to fry. Also, the manufacturers of these things should be subject to international scrutiny, as some of those cordless phones have not only appeared on the ham bands, but also the aviation band as well (nasty!).

73 de VK3JED http://vkradio.com

Yeah, but PL on stops non-hams from expending battery power. 73, Jim wb4gcs@amsat.org

Correct, but not quite that simple. The PTT part of PL hasn't been in use much for a host of reasons that I will not go into now. We could go back to it now, but I've asked the command stations to hold off until a few more pieces of software are ready, partially to retain continuity. Jim White is working on a program to fulfill an idea of mine that will allow a uplink with PL to turn on the downlink transmitter, then immediately switch to the no PL audio path. The repeater and downlink will then be on for n number of minutes with no PL required. After n minutes the downlink times out and another PL'ed uplink will start the loop over again.

This will allow us to do several important things simultaneously. We will be able to save battery power when the satellite is not over users, but at the same time we will not have the same degree of logjam problems because the PL will only be required once or twice per pass. Also as long as one person is PL capable, everyone in the footprint can play whether or not they have a PL capable radio. We'll also be able to hear the QRM and work around it and get rid of it.

With this system anyone will be able to use the satellite given one PL equipped station in the footprint. As common as it may seem to have PL here in the US, this will allow access to more operators worldwide, as well as allow more operators to afford the 2nd radio sometimes required to do full duplex. 2m FM HTs without PL can be had for practically nothing now.

I think this is the best possible combination of both modes of operation.

73, Drew KO4MA AMSAT-NA Vice President of Operations AMSAT LM 2332

At 05:54 AM 2/4/2007, Andrew Glasbrenner wrote:

pieces of software are ready, partially to retain continuity. Jim White is working on a program to fulfill an idea of mine that will allow a uplink with PL to turn on the downlink transmitter, then immediately switch to the no PL audio path. The repeater and downlink will then be on for n number of minutes with no PL required. After n minutes the downlink times out and another PL'ed uplink will start the loop over again.

Brilliant idea! As you say, it will only take a handful of stations with PL turned on to keep the whole thing ticking over, and those of us using memories just have it programmed into our radios.

73 de VK3JED http://vkradio.com