This video shows the use on a 1970’s era HP Spectrum Analyzer, capable of measurements to 110 MHz, to measure Return Loss of an antenna. The 141T Spectrum Analyzer system has the 8552B IF and 8553B RF Sections (plug-in’s), and is connected through a special cable assembly, HP p/n 08443-60009 (see www.glkinst.com to an HP 8443A Tracking Generator (early nixie tube version) The 8443A allows the operator to determine the frequency of any position along the trace via a marker and also provides the incident RF signal to the DUT (antenna in this case) through the 8721A Bridge. This was state of the art for that era and how network analysis was done using this 141T Spectrum Analyzer. These particular units were all built at HP in Santa Rosa, California. The 8721A Bridge is used to seperate the reflected signal from the incident signal and thus measurement of the reflected signal’s amplitude changes over a frequency sweep. See HP Application Note 150-3, available at the HP Memory Project Website, at www.hpmemory.org for more information. Note: the 8721A bridge labels appear on both sides but differently. The connection label LOAD is SOURCE on the opposite side, INCIDENT is actually REFLECTED oppositely, and SOURCE is LOAD on the opposite side. I had it setup to measure REFLECTED but that side is facing the table! Darn! Oh well!) The SA is set to 300 Mhz bandwidth, .5 MHz scan width per division, input attenuation at 20 dB, and a scan or sweep time per division of 5 milliseconds …
Video Rating: 5 / 5
Would have been MUCH MUCH better if there had been something informative about it…if someone could LEARN something from watching it!!!
Yes, I agree. I had just snapped this quick video after running the test, first time I had actually used the 8721A in the shack. It was not intended to be a step-by-step how-to video, but thought I’d put it up anyway. I’ll work on something over the next couple of weeks more informative. Thanks for your comment WA5CVI. FB!
73,
K6SRO
I also have a 141t with the 8553, 8554 and 8555a modules. I like playing with it once in a while. Have the 8406a comb generator too (but still need to learn how to use it!). I remember when I first got this, the 8555a had a bad first stage input mixer module, fortunately found a spare to replace it with, works great. As old as this unit it, I can’t help but be impressed by how much quality went into the design and construction – Made in USA!!!
HP and Agilent today, makes some of the finest measuring equipment ever placed on the market. The quality is required because to measure something, it has to be good and extremely accurate. To get that is not easy with RF and Microwave. Thanks for the kind comments. The 8555A is a fine plug-in and I am lucky enough to have one also. One the the lead engineers on its development is a friend of mine. I am so lucky to have friends like him.
@radiodad2008 Do you have the 8406a comb generator? know how to use it?