We got it.
Among the many files in the records, was the grail I had been hoping for, the minutes of the arguments of the various parties interested in a 3GHz region as presented to the FCC over the course of two days in December 1946.
I’ll write up a proper report of everything I found once I’m back on home soil, as the story is quite long and interesting, but as a quick summary:
It was driven by Raytheon, in advance of their RadarRange and microtherm products.
Raytheon wanted 2600-2700 megacycles, but settled for 2400-2500.
The frequency choice was based on a combination of empirical measurements of heat penetration for various foodstuffs, design considerations for the size of the magnetron, and frequency considerations for any resulting harmonic frequencies.
GE were making a similar product at the time, in the 1000 mc region, and decided that having 2400 open would allow them to generate harmonics from a fundamental of 1200. This, and some other smaller reasons, swayed the FCC towards 2400.
The decision was somewhat rushed, as Raytheon had given the FCC demonstration RadarRanges in August ’46, and was eager to get them to market as it had several large pre-orders. Medical diathermy, and the interference it caused, was a serious consideration at the time, and likely the main motivation for the ISM bands at all, but since it tended to lower frequencies, and the 3GHz region was relatively new territory, Raytheon were able to get 2400 assigned ahead of of the rest of the diathermy driven ISM bands, which still required some deliberation.
I’ve taken hundreds of photographs of the relevant sections of the docket, and will have them all available alongside the report, so that I can reference them directly. I think I’ll have it for you around the middle of June.
Once again, thank you all so much for your support, this literally couldn’t have happened without you.
Today was a good day. Here’s a few snapshots I took, have a look at the previous updates if their significance isn’t apparent.
I had been attempting to access docket 6651, titled:
IN THE MATTER OF ALLOCATION OF FREQUENCIES TO
THE VARIOUS CLASSES OF NON-GOVERNMENTAL
SERVICES IN THE RADIO SPECTRUM FROM 10 KILOCYCLES
TO 30,000,000 KILOCYCLES (Docket No. 6651)
Which was the most relevant docket I could identify from the time period that covered the 2.4GHz range, and is referenced by several sources as being the origin of the bands.
After a few evenings of obsessive compulsive Googling (some 400+ searches according to ‘search history’) with variations on the names and dates of the people I had found to be involved with the proceedings, I found some interesting resources. None more interesting however than the text of the FCC’s addendum to US Code of Federal Regulations which gives us an exact date as to when 2.4GHz was made available (26th of December 1946).
The relevant parts of the code are thankfully available on Google books. You’ll want to read part 18 (page 6498) , or if you find it to be too long, the appendix beginning on page 6506. It outlines much of what we already know regarding the lead up to the bands. (here’s hte link: http://url.ie/h4ij )
More importantly, it mentions a new docket. A key docket. Docket 7858.
I’ve been in touch with the records office at the FCC, and after a few days of digging, because these records aren’t digitised, they think they’ve found the box which contains it.
Following on from the support I received from the last update with regards to travelling to find the documents, I’m in the process of organising a trip in May. There’s a lot of scheduling to do to get the the records, on top of the logistics, but that’s easily handled.
I will of course keep you updated.
One more interesting result of the intensive searching, was a newspaper clipping from the 30th of December 1946, in which Raython announce their RadaRange as an upcoming product. You’ll note in the appendix of the Code of Regulations that the FCC claim to have been asked for a band in the 3GHz (10cm) range, which is in line with the Spencer Microwave patent. I expect to find that Raytheon are responsible for the band, but why they picked 2.4 instead of 2.5/2.6/etc should be revealed in the dockets.
That’s all for now,
Firstly please accept my apologies for the recent radio silence, I wanted to get some details in order before I sent this update out.
The document search company got back to me fairly quickly with regards to the search, and without going into too much detail, there doesn’t seem to be very many breadcrumbs on the docket 6651 search query. They were kind enough to run it through some databases they have access to, and said that since those were coming up empty they weren’t keen on sending someone down to search without more to go on, as they thought we may burn through our research time chasing documents that are hard to locate. I think this is actually quite fair of them, it certainly would have been in their interests to take the job regardless.
As we all know, these documents aren’t available digitally, which, I presume, is why they had difficulty in finding them. Nevertheless, the FCC FOIA attorney I dealt with was reasonably certain that the documents would be in storage, it’s simply a matter of tracking them down.
To that end, I propose that I head out there myself and rummage around until I find them, without the bother of being tied to the clock. I’m sure the background knowledge I’ve picked up would help me find my way, and I can liaise with an FCC archives officer, and the archives research office before-hand so that the materials are ready and the search is good to go as soon as I get there.
That said, this is somewhat of a departure from the original premise of this campaign, the goal is of course the same, but instead of paying the research company, the funds raised will cover an economy class round trip airfare from Ireland to Washington DC, along with a few nights accommodation. It’s important that you all are okay with this change, as I hope you will be, as I think it’s the most likely way to get to the bottom of our little quest; but if there are any concerns I’m happy to address them. I can honestly say that I would really enjoy the experience of coming across the key document personally after all this time.
There’s been no commitments made yet, but as I have some academic commitments to finish up (i.e. my real thesis) this would probably take place in early summer. I’m sure you’re frustrated at how long this is all taking, and for that I do apologise.
That’s all for now, please feel free to email me if there’s anything you’d like to discuss: email@example.com
All the best,
As you recall, I started a Freedom of Information Act request directly to the
FCC because it was both cheaper, and seemed to involve more qualified people.
The Attorney handling the request got back to me, and unfortunately they don’t
maintain records from that period, instead they are likely stored in the
National Archives facility in College Park, Maryland. It is possible to arrange
to visit the archives in person (if anyone is interested) but it is also
possible to hire the document company I was originally going to use to retrieve
So we’ve kinda gone round in a loop – though now that the funds have been
dispersed I can go ahead and authorise the company to begin, which I’ve just
The curious folk (all of you, I presume, since you funded this scheme!) can read
what I sent at the bottom of this message.
They were very fast to replay last time, so hopefully we can get real work
started this week.
Thanks again guys,
I’m interested in obtaining copies of documents regarding the designation of the
2400-2500 MHz band as an industrial, scientific and medical band, specifically
as it was addressed in FCC hearings between December 1946 and May 1947.
I was in contact with your group previously, but am now able to accommodate the
handling fees that were mentioned.
After initiating an FOIA request, I have been informed that the documents I am
seeking are likely stored in the National Archives facility, and that BCPI may
accommodate a search request, is this correct?
My previous email, which should be appended to this one, detailed what I know
about where the documents might be found; further advice has suggested that
Docket 6651 may be the most likely candidate for holding these documents. Though
this is believed to be a broad reaching docket, which, over time, encompassed a
number of updates to the frequency allocation table it proposed.
The most promising avenue is a paragraph taken from the 1947 FCC Annual Report
which reads: “Public hearings on these proposed regulations [ISM], participated
in by medical, industrial, and other interested parties, were held in December
1946. The resultant rules were adopted May 8, 1947”
It is the copies of those hearings that I am interested in. Unfortunately the
report does not specify under which docket they were held.
Thank you for your time and I look forward to hearing from you,