---
title: "Replacing the VHF modulator with a UHF modulator on the ZX81"
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published_at: "2024-06-04T10:14:35+00:00"
modified_at: "2026-03-15T19:56:42+00:00"
author: "David Anderson"
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excerpt: "One-page user guide by Robert Fischer explaining the machine code sort routine for Pro/File 2068, covering usage of the auto alphabetizing feature for TS 2068 database files."
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document_url: "https://archive.org/details/computer-continuum/Replacing%20the%20VHF%20modulator%20with%20a%20UHF%20modulator%20on%20the%20ZX81"
pages: 1
document_date: "198x"
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---

# Replacing the VHF modulator with a UHF modulator on the ZX81

One-page user guide by Robert Fischer explaining the machine code sort routine for Pro/File 2068, covering usage of the auto alphabetizing feature for TS 2068 database files.