HFU HF Underground
Technical Topics => Part 15 AM and FM Station Operation => Topic started by: ThaDood on April 29, 2020, 1725 UTC
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Huh... Looks like a new Part #15 AM TX is in development. https://parkinglotradio.com/ It will be neat to see what becomes of this.
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* When and how can I get one?
We plan to release the product within a matter of a few weeks.
https://www.fcc.gov/engineering-technology/laboratory-division/general/equipment-authorization
Ain't gonna happen.
~
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That's a nice Grundig they're using for testing.
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With a dipole at about 20', my Ramsey FM-25A with no jumper in place has a usable range in excess of 1200' measured on my car radio driving around the 'hood. This level of transmitters costs about $100 at most.
Just wondering why the effort to go AM with all the attending problems with hum and antennas, when an inexpensive Part 15 compliant FM transmitter is easier to implement for equivalent coverage. Besides, a TH AM transmitter already exists and costs less than $250.
For $120, you can get a Part 15 compliant USB stereo FM transmitter with RDS.
The assertion and reasoning for the product development (from the Radio World article) that the RF limit for Part 15 AM is much greater than for FM doesn't translate to better coverage.
Not convinced a church would be willing to dig up the yard and parking lot to accommodate the radial field needed to make this AM transmitter cover even a modest area with a clean signal.
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Well, that's better than what they are charging for this, http://www.progressive-concepts.com/transmission-equipment/part-15-transmitters/---ACC100-Part-15-FM-Transmitters-Analog_PT687.html
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https://fccid.io/MBMACC100
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For $300 I want a device that has a proper 120VAC IEC power cord connector, and a good linear power supply internal, not some cheesy 15vdc switching wall wart. Not like at Part 15 output levels they are spending a lot on the RF section. And it has crap for inputs and no other features at all other than price.
This is a way better buy for church radio, IMO, and les than half the price right now at $179 [size=78%]https://rolls.com/product/HR70 (https://rolls.com/product/HR70)[/size]
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They have a GoFundMe to finance this project which, so far, has raised $100 towards a $20,000 goal.
I don't know. I'm not holding my breath.
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Just saw the Parking Lot AM transmitter, and I'd be glad to have something more pro than what most kits have offered.
It's sad in this high tech world that any FM or Am part 15 transmitter under $100 is pretty much a toy, or a cheap kit.
Companies must use a separate "wall wart" supply for their equipment, it may already be approved by an electrical regulator, such as UL, so the company doesn't have to apply for approval on their own internal power supply design.
AM is supposed to have range advantage when following the rules, and I'd guess it's good for voice radio, like the pastor's voice. I don't know about the radial field, the kits don't come with radials, but you could connect to a handy ground like a fence post or faucet, I've heard of people doing that.
Bear
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Why use a wall wart when you could use USB ?
And why not make it on a card that goes inside the computer?
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Why use a wall wart when you could use USB ?
And why not make it on a card that goes inside the computer?
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PCS Electronics still makes a PCI card FM transmitter. VAST makes a USB powered FM transmitter with RDS. Both roughly the same price. About $130.
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Why use a wall wart when you could use USB ?
And why not make it on a card that goes inside the computer?
USB power is often quite noisy, lots of RFI.
A PCI card is not trivial to design or build (been there, done that, got the t-shirt), and limits the market.
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Typical USB switching noise is bad enough, but inside the computer is a whole other mess for RFI mitigation, power conditioning, etc. o.0
Take a look at the RF shielding on even an old-school basic WinTV PCI card compared to the often pratically non-existent shielding of a cheap RTL-SDR USB tuner.
^There are several interesting VHF/UHF tuner, demodulator, etc, chips on those old WinTV cards. Too bad any serious interest did not take off in the SDR community, as the cards often can be found for around $10 or less these days.
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No updates on the transmitter since October 2021. Wonder if it will ever hit the market.
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Saw in the Carl Blare blog that Parking Lot radio transmitter is not going to happen, a few hours later the HB forum reported the same thing. Here's a copy of their announcement:
"After careful consideration of the general market, supply chain and logistics issues,
as well as FCC licensing costs, it has been deemed that we will be unable to proceed
with the production of Parking Lot Radio.
For those of you generous followers that committed funding in advance,
please contact Jim Hendershot at jim@radiodesign.com
for details on how to receive a refund.
We appreciate your support and offer our apologies for the inconvenience.
We sincerely thank you for your interest in Radio Design Group and our products.
We hope you’ll find our continuing communications helpful and informative.
Follow our social media pages for more!"
Is getting transmitter tested for certification really that much of an expense?
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Yes. Getting a transmitter tested for FCC approval can run into the 5 figure category.
+-RH
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Yes. Getting a transmitter tested for FCC approval can run into the 5 figure category.
+-RH
I didn't realize a multimeter and a measuring tape could cost so much
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I'll keep your reply in mind the next time I'm looking for a noise source from an unverified Chinese white box good.
+-RH
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Excerpted from
https://compliancetesting.com/how-much-does-fcc-testing-cost/
Which Type of Testing Is Right for You?
The total cost of FCC certification depends on the type of FCC testing that you need... ...The most rigorous type of testing is FCC Part 15 Certification. The purpose of this testing is to verify that the electromagnetic interference, or EMI, emitted by your product does not exceed the FCC’s limits....
Average Cost of Testing.. First, keep in mind that the cost of FCC testing depends on several factors, including the type of electronic device you are selling into market and how much work is involved within the testing process. That said, there are a few average estimates that you can use as a guide.
Generally speaking, one can expect to pay anywhere between $3,000 and $5,000 for FCC testing. However, testing for modules & more complex devices can be much costlier. In addition, it is important to take other expenses into consideration, such as the cost of labor. The total cost is also influenced by how extensive the testing process is....
Armchair speculation tells me basically all that's needed for certification with 15.219 is the 100mw input at the final stage and a confirmation its not emiting spuriuos waves. What justifies a thousands of dollar price tag for that?
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A testing laboratory with NIST traceability, special anechoic chambers, millions in test equipment and specialized antennas. That's why it costs so much. From the ouside looking in, it doesn't make sense until you've seen how certification is carried out.
+-RH
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Agreed. I used to be involved with Part 15 certification of computer networking equipment. $10k was what it cost the company at the time back in the 80s.