These two units are very similar, this is a tabulation of the test of one unit.  I tested it at increasingly narrow spans, thereby reducing the resolution bandwidth, this data is from the last set of analyzer displays with the span running from 2.05 GHz to 2.2 GHz.  At broader spans the resolution bandwidth "bins" the results and they are less accurate - in fact if you look at the first set, you can see that 75 and 76 MHz both are shown as producing the same frequency - to be expected with a wider resolution bandwidth (RBW) because both landed in the same frequency bin.

Zeta Laboratories was a U.S.-based manufacturer of RF and microwave components, producing specialized modules such as frequency multipliers, converters, and oscillators for telecom, aerospace, and defense applications during the late 20th century. Public corporate records show Zeta Laboratories, Inc. active in California by at least the mid‑1990s, with a recorded incorporation date of November 7, 1995, and later listed as inactive. The exact founding of the original RF operation likely predates this filing, as was common for small microwave firms that reorganized corporately over time. By the mid‑2000s the company was no longer operating independently; its CAGE code (31260) is now associated with DRS Codem Systems of Sunnyvale, CA. Codem Systems was acquired by DRS in August 2005, and DRS itself became part of Leonardo (Finmeccanica) in 2008, reflecting the broader consolidation of the defense electronics industry during that period.