Talk:Squarial

Technology section description incorrect?

There are problems with the description of the technology of the Squarial. The description of the antenna as being a set of resonant cavities doesn't seem right as the antenna was essentially a microstrip patch antenna coupled to an LNB. There were no resonant cavities of the type described in the article and there were no wire probes either. Jmccormac (talk) 22:04, 2 January 2019 (UTC)

I wrote that. Well, the resonant cavities sounded a little funny to me too, but as you can see from the citation, the information is from a technical text I found which is the only WP:reliable source in the article, so I felt I had no choice but go with it. The other links are broken. Keep in mind that there were apparently several models of the Squarial, which may have had different designs; this may describe the Matsushita units. If anyone can come up with adequately sourced info which contradicts this, I'm fine with changing it, or at least indicating there are conflicting descriptions of the antenna. BTW, most of the previous article content was a cut-and-paste WP:COPYVIO from British Satellite Broadcasting, Astra2 website. --Chetvorno^TALK 16:27, 3 January 2019 (UTC)

I found a more detailed technical description in a Masters thesis: Lee (1996) "The Design and Construction of an Electronically Beam Steered Phased Array Antenna", p.2 which confirms your view. The antenna was a PCB microstrip antenna backed by a reflector. Apparently to reduce sidelobes the antenna was sandwiched between two additional PCBs with shielding planes, with cutouts for the antenna patches. It says the antenna proved impossible to manufacture with the close tolerances required at 12 GHz and was a failure. That should probably be in the article. --Chetvorno^TALK 17:11, 3 January 2019 (UTC)

The original design shown to the press seems to have been the resonant cavity model. ( http://www.tekkiepix.com/Squarial.html ) This was the one that was too complex to manufacture. The Squarial model that made it to market was the sputtered microstrip model with a PCB made up from the film with the microstrip array, a foam dielectric and groundplane. This got around the problem of using extremely expensive high dielectric constant conventional PCB material suitable for microwave frequencies. The production model of the Squarial actually worked quite well and the printed array and foam combination was a nice solution. The problem was the cost. It was impossible for it to compete with cheap metal dishes which could be stamped out and produced for a fraction of the price. It might be interesting to take a few photos of a Squarial's design. Jmccormac (talk) 18:01, 3 January 2019 (UTC)

Your account sounds plausible, but the Trekkiepix article doesn't actually say all that. It does show a disassembled Squarial with what look like resonant cavities, and confirms there were two versions of the antenna, and the second version manufactured by STC worked. The Lee thesis says the microstrip model was the one that couldn't be manufactured due to tolerances. However it was just a short paragraph written by a graduate student in the history section of his thesis, and I am willing to believe he got it wrong. But it would be nice to find a better source for this, that describes the construction history of the antenna in detail. --Chetvorno^TALK 04:07, 5 January 2019 (UTC)

hands-on experience of rigging a squarial

I have no idea how to avoid the wikipedia police & get something into the article about how easy these things were to deploy, but they were. so I know this sort of stuff doesn't belong on the talk page, because I'm not strictly-speaking talking about improving the article, UNLESS someone can work out how to make this less OR/anecdotal:

in march 1990, I worked briefly at crown house in hammersmith, where a small studio did live news bulletins & other shows for all five BSB channels. on the friday before the launch, we rigged an off-air receiver & television in the main production gallery, & I went to the roof with the precious squarial & a compass. no inclinometer. I pointed the thing as near to 37 west as I could, & aimed it over the nearby buildings, then went back inside, & was astonished to see test card G on the telly- no cross-colour, absolutely pin sharp on the 5MHz grating. I went back outdoors & tightened the nuts on its bracket. job done.

a few weeks later, I was on a football OB at (iirc) selhurst park, which was a live into the sports channel for the production company 'champion'. they had rather optimistically provided the OB company (chrysalis mobiles) with an IRD & a squarial. "here, you've worked for this lot," the unit manager laughed, "see if you can make this work." the other racks engineer poked the end of the IF cable out onto the roof of the truck, where we normally rigged a UHF antenna for terrestrial broadcasts (though we never needed this latter at selhurst park!) while I clambered up & squinted at the horizon in a 37-westerly direction. no compass this time, or inclinometer, so I pretty much just waved it around on the scaff pole until the call came from below, maybe thirty seconds, & this time the other engineers were the astonished ones.

duncanrmi (talk) 04:21, 5 January 2021 (UTC)

Just took a look at a Squarial that I have here. The mount on the back of it has an elevation angle guide on the left hand side of the mount hardware where the elevation angle for the dish could be set. Once the elevation angle was set, it was a case of getting the azimuth right and then tweaking for the best signal. It really is a nice bit of engineering.Jmccormac (talk) 09:06, 5 January 2021 (UTC)