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[aprssig] OT: FRS & Type Acceptance WAS: Clubs, FRS ...teams

Steve Noskowicz noskosteve at yahoo.com
Sat Sep 3 01:33:02 UTC 2011


> > >--- Bob Bruninga wrote:
> > > ... FRS radio ...on the roof...6 volts up and bring down speaker 
> > >...... 200' away. ...
> > > ... it can only be used with type-approved accessories

--- And that Steve Noskowicz wrote:
> > Cool idea, but ... a 200' power and speaker extension
> > cable,[stretches]  the rules  ... (;-)

--- Then responded:
>...The type acceptance only applies if he were to attempt to transmit...
> 
> If type acceptance were required for reception then none of
> us would be able to use modified radios, scanners, or
> anything other than a service-specific type-accepted radio
> to listen to other frequencies, right? :)


-- To which Steve comments:

Hi Alex,

   Not quite.  There are several fine points, but I'll try to keep it short and may appear to miss some significant details in the sprit of an overview.

  I did see that part of Bob's comments. I won't go into full detail unless you want, but there is a fine point I'll clarify.  Please accept this as friendly mentoring (for everyone reading).  I hope my comment to Bob didn't sound like I was jumping on him. I did think his idea was clever, as I frequently do of his ideas, and couldn't resist opportunity for the pun.

  Also, I am not an FCC nazi type.  I'm only pointing out a technicality and stand by it based on my experience managing a validation/certification department at Motorola. Some of the FCC rules do appear to conflict with others.
  To the letter of the law, the 200' line is not an approved accessory and its use is unapproved. I am pretty sure that that part of the (applicable) rules makes no distinction as to whether or not the device is transmitting.    It is not just transmitters that require careful desigh when it comes to interference portential.   [to be clear - I am not bothered in the slightest by Bob doing this it]

  Type acceptance is no longer the accepted terminology.  Radio equipment manufactured for use in the various services in the U.S. is now "certified" to meet the rules/laws.  The equipment receives a "Grant of Certification" from the FCC. 
 When required, the certification process is the rigorous measurement of a typical unit for very extensive, specific and detailed parameters that must be measured to show they meet all of the FCC requirements for use in a specific radio service.  This includes both transmitter and receiver parameters.   In addition, the radio must also meet the Part 15 limits of potentially interfering radiation.  In fact, and in principle, *everything* must meet Part 15 limits, even power lines.

  FRS radios are not certified in this manner under any service.  They (the ones I have) are Part 15 intentional radiators of RF.  They are only certified to not radiate harmful energy above Part 15 limits.  None of the transmit or receive parameters are certified (except, perhaps tx power - I haven't examined any FRS specific requirements).
   For certification, a 'typical' unit is put in a special chamber, operated under 'normal' conditions with accessories (this could take several test runs with different accessories) and the radiated emission are measured across the RF spectrum.  
  Adding any "unapproved accessory" increase the likelihood that the Part 15 limits will be exceeded.  It could be a processor clock in the radio that 'leaks' to the cable. A 200' cable can cause it to do so and since it was not measured for certification with such a cable attached, it is clearly outside the letter of the rules.  Whether it *will* cause interference is another matter completely.  It is not certified and not included in the Grant. 


Amateur Radio Service.
  As Hams, we have a special blank check to do (pretty much) whatever we want within the rules (and practically speaking - as long as we don't interfere with anyone or anything and nobody complains).  We are on our own to obey the rules in regards to equipment construction and operation.  We are supposed to know what we are doing.  Police, Fire, taxi cab drivers and cell phone users are not supposed to (technically speaking).

   Amateur equipment does not Intrinsically require any such certification for the FCC  [except for external power amplifiers]-- even though they DO intentionally radiate RF. Remember the blank check?.

  Commercially manufactured Amateur radios fall under Part 15 (I believe always) as though they are scanning receivers in the unintentional radiator section of Part 15 - strange, but true.  The only thing certified is the radiated emissions under Part 15.  Keep I nmind that Part 15 is concerned with the stuff radiated from the box and required wiring and accessories, *not* conducted out the antenna connector.

Regarding listening on other frequencies...  Manufactured scanning receivers fall under Part 15 unintentional radiators.  Hams modifying equipment for themselves falls under the blank check.

Then... with the current FCC. all this rigor seems to be irrelevant .  I find it particularly "interesting"  that the FCC has something like Part 15, yet recently has demonstrated a complete lack of the most fundamental RF knowledge in approving things like BPL and Lightsquared.  Just more "follow the money", I guess

I did intentionally omit some details, so if even some of this seems to be self conflicting, Contact me and I'l try to clear it up.

-- 
 73, Steve, K9DCI   USN (Vet) MOT (Ret) Ham (Yet)
--
I served during the cold war, so you can continue to be served a cold one.

More Details, Features, Contact me and Downloads at:
  http://k9dci.home.comcast.net/




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