The scenario where neither A or B can hear C or D, but that C or D are QRM'd by transmissions from A or B is indeed possible, but is relatively infrequent. No one expects A or B -- whether they are attended or unattended -- to suspend transmission to avoid QRMing a station that neither can hear.
The more common scenario is that A can't hear C or D, but B can hear C or D. A contacts B. If B is attended, he or she detects that the frequency is in use, and either remains silent, or transmits something quick like "QSY to 14085". If B is unattended and without a busy frequency detector, its responds to A, QRMing C and D. It is the latter scenario that is responsible for most of the QRM from unattended stations responding to attended stations (often referred to as "semi-automatic" operation). The fact that we can't cure the first scenario is no excuse for not curing the second scenario, especially given that the second scenario is far more common than the first scenario. 73, Dave, AA6YQ --- In digitalradio@yahoogroups.com, "DuBose Walt Civ AETC CONS/LGCA" <[EMAIL PROTECTED]> wrote: > > A & B hear each other but dont' hear C & D. But C hears either or both A and B. > > If C is receiving D, then A or B is QRMing C. > > Walt/K5YFW > > -----Original Message----- > From: digitalradio@yahoogroups.com > [mailto:[EMAIL PROTECTED] Behalf Of Danny Douglas > Sent: Wednesday, December 13, 2006 12:22 PM > To: digitalradio@yahoogroups.com > Subject: Re: [digitalradio] Re: Dec 15? > > > HMMM By whom is C being QRMd. You didnt say who he is hearing as QRM. I am > assuming that C is hearing either A or B or even both? In this case, if A > and B were already in QSO, then C and D should QSY to start their QSO > elsewhere. > > If the C and D QSO was already underway, and A and B started up, and they > were not hearing either C or D (not probable as usually prop is two- way if > it is strong enough for QRM) then C and D would either put up with it, or > move since under this condition, they cant tell the other pair that the freq > is in use. > > It is prudent for both parties, starting a QSO to insure that neither of > them is intefering with an ongoing QSO, and by both checking to see (both > automatic stations having the capability) if the freq was QRL - it would > avoid inteference to others. > > > Danny Douglas N7DC > ex WN5QMX ET2US WA5UKR ET3USA > SV0WPP VS6DD N7DC/YV5 G5CTB all > DX 2-6 years each > . > QSL LOTW-buro- direct > As courtesty I upload to eQSL but if you > use that - also pls upload to LOTW > or hard card. > > moderator [EMAIL PROTECTED] > ----- Original Message ----- > From: "DuBose Walt Civ AETC CONS/LGCA" <[EMAIL PROTECTED]> > To: <digitalradio@yahoogroups.com> > Sent: Wednesday, December 13, 2006 12:56 PM > Subject: RE: [digitalradio] Re: Dec 15? > > > > If A and B can hear each other but can't hear C or D then if A or B > transmits and C is receiving D, then C is QRMed and can't copy D. > > > > This is something that happens quite often on HF and I don't think that > any amount of coding willremedy this problem. > > > > Walt/K5YFW > > > > > > > > Connect to telnet://cluster.dynalias.org a single node spotting/alert system dedicated to digital and CW QSOs. > > > Yahoo! Groups Links >