In Austin channel 7 (KTBC) was it for several years. They were the official CBS affiliate, but they showed certain programs from NBC, DuMont and ABC.

The following from Wikipedia Primary Programing:
CBS (1952–1995)
Secondary Programming:
DuMont (1952–1956)
NBC (1952–1966)
ABC (1952–1971)

Everything was pretty well off the air after 12:30 or 1:00 AM coming back on around 5:30 AM.

The Second Station To Sign On:

In 1962 PBS was first aired in Austin with the call letters KLRN. It was a collaboration between Austin and San Antonio, and was shown on channel 9.

It broke away from the San Antonio PBS affiliation in 1979 to become KLRU, channel 18.

Then There Were Three:

I believe the next to come on line by the mid 60s was a NBC affiliate, channel 42 and the call letters were KHFI. It changed within a few of years to channel 36. I can’t say for certain but it seems like it didn’t change to KXAN until much later.

Comment: Saw your blog about the early days of Austin TV and thought I’d clarify a couple of things regarding KXAN, since I worked there in the mid 1970s. Regarding the KHFI TV designation…the call sign history is that it switched to KTVV TV (with a transmitter upgrade and switch from channel 42 to channel 36) in early 1973, and in 1987 flipped again to KXAN. The call sign switch to KXAN was primarily a marketing thing.

Then The Forth Channel Came:

Later in the early 70s channel 24 entered the market with KVUE being the call letters, the ABC affiliate.

Then There Were Five

By the 1986 Fox hit the airwaves at channel 42, KBVO.

Then in 1995 Channel 7 and 42 had the big switcharoo with Fox moving to channel 7 and CBS going to 42.

By the early 80s Austin Cablevison was being installed around the city and several other competing networks were introduced and it went on for there.

Please feel free to correct me if some of the dates above are incorrect. Most was done from memory, with some help from Wikipedia. I’ll be happy to edit as needed.

Early Days Keeping A Television Operating

But more striking than the few viewing choices we had is the equipment we watched it on. The adjustments that we constantly went through to keep the picture from rolling.

The mass of tubes in the back of a TV set were constantly needing attention it seems like. Below are pictures of a few things that should bring back a lot of memories. Many dads had to become self taught TV repairmen.

Tubes would be removed and taken in to various places to test and then buy replacements. It seems to me that we mostly went to a 7/11 type convenience stores to buy replacements tubes.