If you think your savings are well guarded, then you probably shouldn’t look at MRAM’s experimental website. It has a beautiful picture of The Comtek! If you gaze upon it, you may break down and order one today as I’m trying not to do.
http://mram.gotdns.com/
thevalley1700am says
Neato
So does this operate on the old analog TV frequencies?
-Geoff
NEXTGEN.FM
kk7cw says
Suggestion
I strongly suggest that all who consider this option read the last two paragraphs on page one of the manual (link above). The mentioned suggestions have historically been the accepted uses of these devices. In its R&O, has the FCC released these devices for other uses other than the suggestions stated? If so, these expanded uses would be stated in the R&O. I am not attempting to discourage the expanded use of devices in this part of the spectrum, however some thought needs to be given to the reason for the FCC requiring, even for a short time. a waiver for usage. These devices are not intended for this use as broadcast transmitters, but rather as short distance program material relays. Even if the ultimate reception is the public, as in the old model for community antenna TV.
In addition, please read the R&O and consider the distance requirements for co-channel use in the new section 15.238. To qualify, these devices can only be used in areas with no channel 5 or 6 signal contours covering the site of the Part 15 transmission. Inside these television station signal contours, use of these devices would be illegal or severely restricted.
I would welcome any new information regarding where the FCC is taking this R&O or new developments in the comment window for this action.
tbone903 says
Wireless Audio Device
Present uses for the Comtek BST-25 aside, would you say that this device meets the criteria of the new Part 15.3(hh)? Does it comply with the Part 15 technical rules in the new 15.238?
If it does, would it not then qualify for use as a baby monitor, Sirius/XM modulator, or even a type of remote speaker system?
I agree that use would be limited to areas without a TV Ch. 5 or Ch.6, but that has always been the case…licensed or not.
PS- I forgot to mention…the comment period expired in March, I believe. We may hear something about the changes as soon as the 30th of November. The FCC has TV spectrum stuff on the agenda for their meeting, but whether they will make a final desicion on this is anybody’s guess.
kk7cw says
Answers
I will try, as best I can with the limited information available on this topic from the FCC, to answer a couple of your questions.
Your question: “would you say that this device meets the criteria of the new Part 15.3(hh)?”
Excerpt from 15.3(hh) – “Transmission of audio material to the public switched telephone network and private and commercial wireless systems and networks is not permitted.”
My opinion: I will assume this means that the audio in this system to which the device is connect, cannot be used in conjunction with public wired and wireless systems and networks. This precludes putting callers on the air or doing anything that looks like a remote broadcast through this device. It cannot, as a result, be used for a studio transmitter link for broadcast on the internet or over the air program content. The section mentions “short distance” which is yet to be defined, except as may be mentioned in other sections of Part 15 frequency allocation and usage.
Your question: “Does it comply with the Part 15 technical rules in the new 15.238?”
Excerpt from 15.238 – “(3) The frequency tolerance of the carrier signal shall be maintained within +/- 0.005% of the
operating frequency over a temperature variation of -20 degrees to +50 degrees C at normal supply voltage, and for a variation in the primary supply voltage from 85% to 115% of the rated supply voltage at a temperature of 20 degrees C. Battery operated equipment shall be tested using a new battery.”
My opinion: If the published specifications of the Comtek BST-25 are consistent with the bandwidth and frequency tolerance sections of this rule, there is a possibility this device could pass this section of the rules. However, the recent inspection case law involving the operation of certain Part 15 certified equipment and the resulting NOUO’s (KENC, Liberty 1640) point to the possibility that the FCC may inspect for compliance and because the specific operation of the device and what it is connected to, find it out of compliance. These new rules will require inspection case law or inspection experience to know for sure the intent of the rules. It is good to remember, the FCC sees the application of any RF intentional radiator in the totality of the rules, not just one section.
And finally, In my 40+ years of dealing with the FCC, I have seen R&O’s sometimes stand for years without final action. And in this case, because of the political “hot potato” the vacated TV band space has become, the FCC will not act on this issue anytime soon. Let’s not forget, the Congress can pass laws that will reverse final FCC action and have done so in the past.
mram1500 says
From the Horses Mouth
I requested info from Comtek about the BST-25. Here is what they said:
“Hello Robert,
Please be advised that the BST-25 base station transmitter operating in the TV 5/6 band (76-88 MHz) is certified under FCC Part 74. Attached please find the operators manual that shows the technical specifications and frequency range of this transmitter for your review.
We did have an older model transmitter, the BST-50, that operated in the 72-76 MHz band that was certified under Part 15, however, we have not built this model for around 30 years. The current version, the BST-50b, also operates in the 72-76 MHz band, and is certified under Part 90. We also have a BST-25/216 base station transmitter that operates in the 216-217 MHz band and is certified under Part 74 and Part 95.
Please let me know if you have any other questions. Thank you.
Best regards,
Jon”
I have replied to Jon as it was suggested here that perhaps the latest Part 15 changes would allow their unit to operate under Part 15 rules.
I made it clear there is interest in using their unit as a Part 15 unlicensed FM transmitter at the bottom of the FM broadcast band.
Time for a Wait and See attitude.
Carl Blare says
Put On Hold
Based on MRAM’s communication with the Comtek people it will be necessary to put Comtek dream on hold for now. But I beg to differ with one opinion expressed by Mr. Marshall Johnson, Sr.
Marshall quoted this reprint from FCC Part 15
Excerpt from 15.3(hh) – “Transmission of audio material to the public switched telephone network and private and commercial wireless systems and networks is not permitted.”
I would say that the key word is TO.
You cannot transmit material TO the various named distribution systems.
However, obtaining signals FROM certain public networks is not prohibited, e.g., callers for your talk show.
tbone903 says
Time will tell…
I do agree that the ‘waters are still murky’ on this matter, but time will tell. The loosening of restrictions on the unlicensed use of the TV bands are, however, a matter of record.
It is my opinion, that the use of a Comtek BST-25 without a license, as of this moment is completely legal, and any enforcement action could be challenged in a court of law. Provided you have the resources to persue such an endeavor. Which I am sure most of us on here do not.
As with anything government-related, rulings usually come down at a snail’s pace. Unless your a huge financial institution that’s ‘too big to fail’, and need a bail-out.
Just for the record, here is another source of information that paints a great picture of unlicensed use of TV Bands, from PillsburyLaw.com, a Washington DC law firm.
(It’s dated information as of June 12th, but only in regard to the use of the 700Mhz band.)
http://www.pillsburylaw.com/siteFiles/Publications/B5D9D6290692F633F499721193F29EAD.pdf
Carl, you are correct about transmitting TO a public switched telephone network. This matter is explained in detail in the document linked above.
In addition, the comment period for the NPRM has expired. The Commision was moving quite quickly to get the TVBD ruling slammed through this past September, and that ruling will indirectly affect what the decision of this matter will be.
In any event, be sure to keep an eye out for that Comtek BST-25 on E-bay! I got mine for about $350…cheaper than a Rangemaster!
Carl Blare says
A Good Part of the Puzzle
Thanks tbone903 for this informative link, which spells out much of what’s been discussed here.
Finally I know that the “Core TV Band” is channels 2-51.
The section on “Interim Operation” is the heart of it for us.
mram1500 says
Ohhh Man!
I hate to pop bubbles but I’ve said this before: It doesn’t matter if you run 100% legal-all that’s needed is a claim of interference and bye-bye. Or as in the KENC case, just an annoyance and bye-bye.
So it really doesn’t seem to matter how legal you are, but rather how unobtrusive you are not that I advocate Pirate Radio operations.
I’m not paranoid but that doesn’t mean there isn’t somebody out there trying to get me.