My understanding is that the 1200 filter is used more often than not,
but that may be specific to the Northeast US where I fly. Controllors
who think they are busy can activate it to reduce their work load.
Corollers are only reposible for IFR-IFR traffic separation, and are
not required to report VFR traffic, even with a transponder. IFR pilots
in VMC are still responsible for see and avoid.

It is good that you have 0440 assigned for Gliders with Reno. There are
a similar patchwork of agreements with other centers. I think
Philadelphia approach uses 1202 for towplanes. There are various codes
for Baloons and Airships too, which may be in conflict between areas.
What we really need is a national set of these used universally.

Jeremy Zawodny wrote:
Eric Greenwell wrote:
Doug Haluza wrote:
Most ATC sections filter out 1200
VFR codes, and only view aircraft with discrete codes. So in this case,
even if the glider's transponder was on, there is no guarantee that the
controller even saw it, much less gave a traffic warning--they are not
required to warn IFR aircraft of VFR targets anyway.

Whoa! Really? Isn't that the point of requiring all airplanes to carry
transponders? What I've heard from multiple sources is the only places
the VFR code is filtered out are areas with VERY heavy traffic (and
where VFR traffic is confined), like over Los Angeles. Knowledgeable
people that fly in the Minden area and discuss things with ATC there
have never suggested that Reno is filtering out VFR codes!

And many (most?) glider pilots flying in the Minden area squak 0440
rathern than 1200. There's a letter of agreement in place with Reno ATC
that permits gliders to use 0440 as a way of telling ATC that the
aircraft is a glider. This eliminates the need for more radio chatter
and could make their filtering easier, assuming they can filter based on
the codes.

Jeremy