Question for the experts about FCC type acceptance or approval of a 1-off BC XMT

[steve_qix]

Hi !

I have been approached to build a 10kW broadcast transmitter for a station owner who cannot afford a commercial unit.  Currently, they are using a vacuum tube transmitter, and it is eating them out of house and home, electric-bill wise.  The goal is to be able to cover the entire cost of the new transmitter with 2 years or less of electricity savings.

But, the question of FCC type acceptance or FCC type approval is there.  Does the unit have to type accepted or type approved?  I have not been able to figure this out, and certainly I do not want to get anyone in trouble by not doing what is necessary to make everything legal.

This would be a one-off - no other units are planned, just this one.  The owner has very modest requirements with respect to remote control, etc. and doesn't want support for IBOC, so this shouldn't be overly difficult.

I was thinking of just calling the FCC and see if I could find out about the type approval / type acceptance issue there, but maybe someone here knows about this.  That would be great!

Thanks and Regards,

Steve

[KC9LKE]

Sounds like an interesting endeavor.

Yeah the question is …if the completed unit can pass FCC specs then its good to go.
OR
It passes and has to then be blessed by some entity. Like having a piece of eqpt accepted by UL.

Interesting
Ted / KC9LKE   

[KA3EKH]

AM or FM? 10kW in AM is an unusual amount unless it’s an expanded band AM station, 10 kW days and 1 kW night ND; don’t know who in their right mind would build a directional AM these days. In FM all stations are rated in ERP but fall into three classes, A,B and C with class A being 3 kW , B  being 50 kW and C being 100 kW, 10 kW would not be that odd for a class B when you consider the gain of the antenna or if the antenna is located above 500 feet. Harris and BE produce lots of good transmitters for good money, Nautell and several other companies are cheaper and junk like Energyonix and QEI are out there for the low cost alternative.  Don’t think there is any laws forbidding building your own transmitter as long as it fulfills all the requirements of a full proof but have to wonder why? If someone wants to be in the broadcast business they need to at least be able to afford things like towers, buildings and transmitters or there got to be something wrong, lots of companies sell used broadcast transmitters for a half or third of what a new one would cost but when someone thinks they can build their own for less I would take that as a warning and run away myself, but that’s just me. Kind of like saying, I can build a car for less than it will cost dealing with one of those crocked car dealers and big companies.
RF

[steve_qix]

You can't build a car for less because the cost of the tooling puts you out of the ball park, but you (or I) CAN build a 10kW (AM) broadcast transmitter for less (quite a bit less) than the cost of a new unit because all of the parts are standard, off the shelf components and there is no special tooling required.

This is a 10kW AM station.

[W4AMV]

Steve, I would go to the CFR site to get up to date information, see for example:

http://wireless.fcc.gov/index.htm?job=rules_and_regulations

I have done similar but some time ago and the answer was YES, although in one case it could be self approved and in another I required a second party in addition to self test.

[KA3EKH]

So that will be a 10 kW more than likely PDM all FET transmitter? Broadcast transmitters are rated at unmodulated carrier output so you will need to provide constant 10 kW carrier with capability to produce positive peeks up to a minimum of 125% or 22 kW or so. From experience I know that a Harris DAX uses five  1 kW sections combined to generate 5 kW with a common DC power supply developing around 200 to 250 Vdc and a common exciter and controller card and all that fits into a signal rack. The BE-6 5 kW is a little bigger and uses separate power supplies for each of its six sections. So I would assume that you're going to have to build ten to twelve 1 kW sections and combine their output to get the 10 kW. I can see that by doing this you can maybe get everything into two racks.
Then there's the question of efficiency and recovering cost. I replaced two Harris MW-5 PDM tube AM transmitters with DAX-5 transmitters.  The efficiency of the solid state transmitters is not much better than the old Harris MW-5 PDM transmitters that were installed at the sites. The big saving are in maintenance cost being the MW-5 eat  a modulator tube every year and a PA tube every two years and the cost of the tubes kept rising, also back six or seven years ago there was enough money in broadcasting that we did things like replace twenty year old transmitters to prevent down time. I will be curious to see how it all plays out, not questioning your ability to design and build this  but remember that this transmitter has to run continually day in and day out at full power, survive lightning strikes and power glitches and failures and reliably return to service every time. I am not saying you can't do this but if you design and build it you may be the only person who can repair it, if you're up to that level of challenge and commitment the suppressing second, third and spurious 80 Db and passing a full audio proof is nothing. One of the old time engineers I worked with when I was just a pup use to tell me the stories on how when he got into radio he worked for a station that the owner had two guy from the local college built the transmitter that was in a room you would walk into and use light switches to turn everything on and off.
RF

[WB6NVH]

You can get started by reviewing OET Bulletin 61 from the FCC which discusses Type Acceptance of broadcast transmitters, among other types. It should be available on their site.

In my opinion, the process very much discourages one-off projects, and the economies of scale are against you.

I would think it would be cheaper to just buy a used, manufactured type accepted solid state transmitter.  There ought to be a lot of those out there, although maybe not at that high a power level.  The power bill may not be all that much better, you can figure that out by just comparing the specs.

The vast majority of AM stations are total money losers today as well as a disaster waiting to happen should the FCC do an inspection.  About the only value is the land the transmitter plant sits on.  They don't want to spend money on anything, including rule compliance, much less a new transmitter.  A lot of them have no engineers and wait until the station is off the air to start calling contract engineering firms, and then want to pay them with t-shirts and promotional meal coupons.  Don't ask how I know that!  >:(That's not addressing your question, it's just me being cranky.)

[steve_qix]

This is fairly preliminary at the moment    Before doing anything at all, or even looking seriously into the costs, it is absolutely necessary to understand the regulatory situation because that, above all else, dictates most future actions.

On the station itself, I *think* they've got has some type of transformer coupled, plate modulated transmitter and those babies are pretty inefficient.  If it's a PWM rig, the savings won't be nearly as good - probably wouldn't really be worth it.

I will definitely be looking into used solid state transmitters - this would be a better approach if a couple of 5kW units were available and were reasonably priced.  Even if I build something for this guy, it will be done as 2  5kW transmitters combined.  5kW is very practical to build - nothing is really out of the ordinary with respect to the parts needed, etc.  Also is more reliable in the event of a problem - chances are, both transmitters won't go down at the same time.

My guess is similar to other opinions express here: This is a mom and pop station, and they are most likely barely getting by.  But, they are getting by and that's a good thing.  It's nice to see a station not owned by a chain!!!!

[R. Fry SWL]

Before doing anything at all, or even looking seriously into the costs, it is absolutely necessary to understand the regulatory situation ...

Here is a paste from 47CFR Part 73 with the basic answer.  Part 2 covers the details, and can be accessed on line.

                       TITLE 47--TELECOMMUNICATION
 
        CHAPTER I--FEDERAL COMMUNICATIONS COMMISSION (CONTINUED)
 
PART 73_RADIO BROADCAST SERVICES--Table of Contents
 
          Subpart H_Rules Applicable to All Broadcast Stations
 
Sec. 73.1660  Acceptability of broadcast transmitters.

    (a)(1) An AM, FM, or TV transmitter shall be verified for compliance
with the requirements of this part following the procedures described in
part 2 of this chapter.
    (2) An LPFM transmitter shall be certified for compliance with the
requirements of this part following the procedures described in part 2
of the this chapter.
    (b) A permittee or licensee planning to modify a transmitter which
has been approved by the FCC or verified for compliance must follow the
requirements contained in Sec. 73.1690.
    (c) A transmitter which was in use prior to January 30, 1955, may
continue to be used by the licensee, and successors or assignees, if it
continues to comply with the technical requirements for the type of
station at which it is used.
    (d) AM stereophonic exciter-generators for interfacing with approved
or verified AM transmitters may be certified upon request from any
manufacturer in accordance with the procedures described in part 2 of
the FCC rules. Broadcast licensees may modify their certified AM
stereophonic exciter-generators in accordance with Sec. 73.1690.
    (e) Additional rules covering certification and verification,
modification of authorized transmitters, and withdrawal of a grant of
authorization are contained in part 2 of the FCC rules.

[63 FR 36604, July 7, 1998, as amended at 65 FR 30004, May 10, 2000; 65
FR 67304, Nov. 9, 2000]

[WA1GFZ]

I would think you would need NIST traced test equipment to do a qualification test. So you would need to rent or borrow real test equipment to do a qualification.

[W2XR]

Steve,

Be sure to discuss with this potential customer your and his expectations for long-term service and support. Both parties have to make sure that any warranties and support issues are mutually acceptable from a legal standpoint.

Since you would be providing this equipment to a commercial user, and he may have certain rights in the event your equipment fails (e.g., off-air time losses, inability to support the equipment due to discontinued replacement parts, or your lack of desire to continue to support the product, etc.), I personally would be very, very careful entering into this, from a legal standpoint. I don't think it would be worth it, unless you had an attorney draw up a draft warranty for the customer's review, and the customer finds the terms and conditions of the warranty acceptable.

Just my 2 cents.

73,

Bruce

[W2PFY]

One of the stations that Tim (HLR) works on is a ten KW class D solid state transmitter in his home town. I have seen it and it runs 24/7. I think the only problem he has had with it is the power service panel and not the transmitter. Well anyhow, to get some idea how it is built, perhaps Tim could get a copy of the service manual that may give you further insight of the requirements.  

[kb3ouk]

One of the stations that Tim (HLR) works on is a ten KW class D solid state transmitter in his home town. I have seen it and it runs 24/7. I think the only problem he has had with it is the power service panel and not the transmitter. Well anyhow, to get some idea how it is built, perhaps Tim could get a copy of the service manual that may give you further insight of the requirements.   

it's funny, that was the one person i was gonna suggest that steve should ask about fcc approval of a transmitter. most of the stuff up at WBCQ was cobbled together from various pieces, and i know it had to have been tested, so i would assume that the process of having to get acceptance from AM BC isn't that much different from getting approval to use a SW transmitter.

[k4kyv]

In broadcast jargon that is known as a "composite" transmitter.  I'm pretty sure they are still permitted under the rules, although I doubt many stations go that route any more.  I did hear of a case a few years ago where the CE did some major modifications to a commercially built type-accepted transmitter, and the easiest route with the FeeCee was to declare it a composite transmitter.

My HF-300 rig is built into the remnants of a 1930s composite transmitter.  Also, Hoisy, W4CJL (SK) of S.P.A.M. fame, built a composite transmitter for the station where he worked in Alabama, some time in the late 1970s or early 1980s. As I recall, it was for stand-by use, built mostly out of components the station already had on hand.  I once visited him about the time the project was being completed, and he showed it to me. Nice construction.

[W4AMV]

This found at the latest FCC site... see if this helps guide.

AM Stations

AM stations occupy the frequencies of 540 kHz to 1700 kHz. These stations are allocated on a non-interference basis. To be acceptable, an application for a new AM broadcast station must show that no interference will be caused to other U.S. and foreign AM stations on the same frequency or, on the adjacent channels (out to 30 kHz above or below the desired frequency (see 47 CFR 73.37)). Applications must also consider the second harmonic frequency and intermediate frequency relationships per 47 CFR 73.182(s) (for example 2 x 800 kHz = 1600 kHz for the second harmonic relationship; or 800 kHz + 455 kHz IF frequency could affect reception on 1250 and 1260 kHz). In general, these complex engineering analyses require specialized knowledge and software, and are best performed by broadcast engineering consultants.

Rules. AM station rules include 47 CFR 73.1 through 73.190, and 73.1001 through 73.5009. These rules may be retrieved at http://www.fcc.gov/fcc-bin/audio/amfmrule.html or obtained from the Government Printing Office at the location listed in the Introduction above.

Form to Use, Application Filing Fee. Applications for new AM broadcast stations must be electronically filed on FCC Form 301 during a specified application window period. Noncommercial educational applicants should also use FCC Form 301. Commercial applicants must include the new station application filing fee listed in the Media Bureau Fee Filing Guide and include FCC Form 159 with the fee payment and application. Please note that payments for commercial applications not paid online must be directed to the lockbox address, and NOT the FCC in Washington, DC.

Additional Information about AM broadcast stations and applications may be accessed on the Internet at http://www.fcc.gov/mb/audio/am.html.

NOTICE: THE FCC IS NOT ACCEPTING APPLICATIONS FOR NEW AM BROADCAST STATIONS AT THE PRESENT TIME. The Media Bureau will announce a filing window period at intervals during which new station applications and major change applications may be filed. Filing window announcements will be made via public notice, and notice will also be posted at several locations on the Commission's Internet Web site (including the Headlines section of the Audio Division's main page at http://www.fcc.gov/mb/audio/index.html#HEADLINES).

[Opcom]

Get your money up front, or in escrow at a firm in your pay.

[Jeff W9GY]

I remember years ago of a TV station had a "homebrew" transmitter that could be put on the air if needed.  But it was classified as an "emergency" transmitter, not an "auxillary" transmitter.  Guess that meant it didn't need to meet all the requirements of a tx that was in day-to-day service.   

[DMOD]

As another resource, you might consult with some of the Engineers
at the Virtual Engineer

http://www.broadcastengineering.info/

and

http://www.broadcastengineering.info/viewforum.php?f=27&sid=8669b3be0ba9787d081891b91aaee2b7

Phil

[John K5PRO]

When Omnitronix began to market their PDM AM SS transmitters in late 1980s in Philadelphia, I did the FCC type notification testing and report for them. It wasn't hard, follow the rules and regs. Need a spectrum analyzer for bandwidth and spurious, plus cabinet radiation measurements. And do an audio proof. I think that was it. Took a Saturday to make the measurements, and the equipment didn't need NIST tracability, as long as the engineer signed his name to the measurements (and took the liability if there were complaints).

The letter back from FCC will give you a number to post on the label, FCC notification number.

[KA3EKH]

What did you decide to do? Don’t think you need to do much beyond a full proof and if that’s an issue there are several people on the list that have done this for an AM transmitter and have the equipment. Looking at some of your work with the solid state class E stuff looks like you may be up to the challenge, so what you going to do???