Today at 4000 South Figueroa, Los Angeles, CA is a Chevron gas station. National Tech School was once at this location. Navy Campus management Information System (NCMIS) used it for tech training which was covered under the Coast Guard Tuition Assistance program.
How long the school existed is unclear. The advertisement is from yet another Western Pulp magazine printed in 1948. As I expected they also advertised in Popular Mechanics. The Popular Mechanics ad also listed two branches. One branch in Canada at 811 West Hastings Street vancouver B.C. and another
at 323 West Polk Street in Chicago. A 1949 Railroad magazine listed on Ebay had a similar advertisement. But that one has the important motto "Technical trade training since 1905."
The Journal of Engineering Education still listed the school in 1965. In 1966 the IEEE Membership directory also listed it, still at that address. Sometime in the intervening 40 years it closed or moved and the building was razed.
The American Student Loan Services Directory lists the school as having withdrawn from the Guaranteed Student Loan Program (GSLP) on March 22nd 1977. If that and the 1905 dates are right, the school operated for almost 72 years. But they also list the school as "National Tech School Home Study Division." The ads home training angle suggests this is that same school. If any readers attended this school a little more info would be useful.