OT/National Radio Countdowns

I’m trying to determine (compile) info for most of the national radio countdowns that aired (specifically what years each ran, and which chart was used for the countdown).
I used the Charis Music site and Wikipedia as a basis (and some googling). Can anyone help fill in the blanks (and correct any wrong info)?
I believe all are Casey Kasem-hosted except where noted.

MAIN YEARS 1970-1995:
AT40 - 7/70-8/88 - Billboard Hot 100
AT40 (Shadoe Stevens years) - 8/88-1/95 - Billboard Hot 100 thru 11/23/91; BB Top 40 Radio Monitor (Hot 100 Airplay): 11/30/91-12/19/92; then BB Top 40/Mainstream chart until end

CASEY AFTER "AT40”:
Casey’s Top 40 - 1/21/89-3/98 - R&R CHR (then "CHR/pop" from ’94 on, when their CHR split into CHR/pop & CHR/Rhythmic)
Casey’s Countdown (1st top 25, later top 20) (3 hours) - 5/92-3/98 - R&R AC
Casey’s Hot 20 (3 hours)- 11/94-3/98 - R&R Hot AC
(These all ended in 3/98 when Casey brought AT40 back)

REBIRTH OF AT40 (Casey) after Shadoe:
AT40 (CHR) - 3/28/98-1/3/04 - R&R Top 40/Mainstream thru '09 (except 10/00-8/01 - media base); then mediabase Mainstream top 40 starting 2009
AT40 (Hot AC) - 2004 (or 1998?) until when - R&R Hot AC chart, then official Mediabase Hot AC chart

AT20 (AC) - 3/98-3/20/04 - R&R AC except 2000-01 & early 2003 on: Mediabase chart; then show reduced to:
AT10 (AC) - 3/04-7/4/09 - Mediabase chart; 2005-8/19/06: R&R AC, then Mediabase or unpublished chart
AT20 (Hot AC) - 3/98-7/4//09 - R&R Hot AC except 2000-01 Mediabase chart

RYAN SEACREST:
AT40 (CHR) - 1/10/04-present / house Mediabase chart
AT40 (Hot AC) - 12/8/04-present / house Mediabase chart

DICK CLARK:
National Music Survey - ’81-'85 - Cashbox until 3/12/82; then R&R AC
National Music Survey (hosted by Bill St. James & Charlie Tuna after Clark) - 85 until when? - R&R AC
Countdown America (also included other hosts) - '83? - 86? (at least) - R&R CHR
Possibly: Countdown America (AC version) - years? - R&R?

RICK DEES:
Rick Dees Weekly Top 40 (CHR version) - 9/83-now - Cashbox thru 1/12/85; then R&R -which chart?, then their own chart
Rick Dees Weekly Top 40 Hot AC - years? - R&R Hot AC?
Rick Dees Weekly Top 30 (AC version) - years? - R&R AC?

OTHER NON-CASEY:
Weekly Top 30 (Mark Elliott) - 6/30/79-12/81 - averages sales surveys of the nation’s leading music magazines
(Continuing where the above chart left off):
Weekly Music Magazine (Charlie Van Dyke) - 1/9/82-12/25/02 - their own chart
Rockin’ America: Top 30 Countdown (Scott Shannon) - 84-92 - their own chart until 8/87, then R&R CHR to 1990; then self-published chart after name change to Scott Shannon All Request Top 30 Countdown
Top 40 Satellite Survey (Dan Ingram) - mid-80s (at least 6/84-5/86) - chart?
Hitlist Live with Elvis Duran & Elliot Segal (or Patty Steele?) - mid ‘90s - chart?

I know there’s quite a few question marks here. But hope you guys can fill these in. Thanks.

Edited by EdisonLite

AT40 - 1/70-8/88 - Billboard Hot 100

The first AT40 began in July 1970. If I recall what I read somewhere, it debuted on the July 4th weekend that year.

Dan Ingram did one in the mid-ish 80s, if I'm not mistaken it was called the Dan Ingram Satellite Survey.

I was listening to the radio one day in 1986 and there was some countdown going on with a host whose voice I had never heard before and I
remember hearing him say something about John Cougar Mellencamp's "R.O.C.K. In The U.S.A." falling from 1 to 13. I wonder if this was what I
heard. I don't know what source he used for the countdown, but it obviously wasn't Billboard, Cashbox or Radio & Records since the Mellencamp
song didn't go to #1 on any of those charts. And I don't think it was a local countdown either, as I most likely would have recognized the
voice with the amount of time I spent listening to the radio back then. A year before, I heard another countdown where Daryl Hall & John
Oates' "Some Things Are Better Left Unsaid" fell from 10 to 20 and after mentioning the 10-notch drop, the host said something to the effect
of "Some Things ARE Better Left Unsaid". The Ingram countdown may have been what I heard in both cases. I do remember that a few weeks after
the Mellencamp song was #1, I never heard the program or his voice again.

Scott Shannon hosted Scott Shannon's Rockin' America: The Top 30 Countdown from 1984 to 1992.

The show used their own charts from 1984 to the weekend of August 28–30, 1987.

The show used the R&R CHR Top 30 chart from the weekend of September 4–6, 1987 to 1990.

The show was renamed Scott Shannon's All Request Top 30 Countdown in 1990, and reverted to a self-published chart.

(All info and dates from Wikipedia.)

The Weekly Top 30 with Mark Elliott premiered on 6/30/79. The countdown was based on calculations from the "countdown
computer" which "averages sales surveys of the nation's leading music magazines." I don't recall if they ever actually
stated what those magazines were (I highly doubt it). I remember enjoying the show when I remembered to catch it back in the
day.

Paul Haney, thanks for your answers. Do you know if Weekly Music Magazine
(which continued on the week after Weeklty Top 30 ended) also continued
with the same basis?