----- Original Message -----
From: "Fred Fillinger" <n3eu@comcast.net>
Subject: Re: Europa-List: Transponder issues
|
| > You did not comment on directivity/blanking. You don't suppose
| > those periods of ATC non-reception to be this cause? It seems
| > outlandish but such things do exist methinks. What would you
| > propose? I am interested in your thoughts.............
| > Cheers, Ferg
|
| If your reply lamp is blinking, but ATC can't see it, then under the
| reciprocity law, it's unlikely the antenna installation. However,
| now, there's no way to know whether the replies behind the blinking
| light are associated with the ATC facility you're talking to. The
| radar site(s) ATC is using to interrogate you could indeed be within a
| null area in your radiation pattern, and therefore a likely
| installation issue. In fact, more so lately, you could merely be
| replying to TCAS interrogations from an airplane close by, and many of
| the TCAS boxes blast you with about 400 watts worth of interrogatory,
| I guess for safety and thus legal liability reasons.
| All the more why nothing certain can be deduced from a blinking reply
| light, except a 50-cent lamp is good!
| Reg,
| Fred F.
Right-o, Fred,
About this reciprocity law - I think it was passed while my back
was turned (probably against the wall). If the interrogation system is
anything like the aerochat freqs, the ATC interrogator probably has many
more watts output than does the transponder. That may be reciprocity in the
master/slave market, but is it true for the ATC txpdr too?
cheers, Ferg
Could we make a fortune trading the 50-center for a dime LED?
|