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Author Topic: New Narrowbanding Laws and Equipment Certification  (Read 12497 times)
KT0DD
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Posts: 353




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« on: June 17, 2015, 07:32:11 PM »

There is so much confusion out there, especially with all the dubious "Part 90" type accepted chicom radios.

I am shopping around and was wondering if a radio that is advertised as "Part 90 Certified" but it doesn't offer the 2.5 KHZ channel step for splinter frequencies, is it really "Part 90" Type accepted? There are several sellers out there advertising the Wouxun KG-UV6D /X versions with 2.5KHZ steps and Part 90 Cert. and then they also advertise variants KG-UV5D, KG-UV2D etc. that they say are Part 90 approved but they only have the 5khz and up step size. They all list the same approval number: FCC ID: WVTWOUXUN04. They all have the capability of narrowbanding 12.5/2.5 width/deviation and lock out of the VFO by computer programming.

I don't need splinter frequencies as all I would need is something to be compliant for county volunteer SAR work(they use old VHF channels that aren't splinter freq.) that's also Amateur compatible on 2m/70cm.

I just want to pick the right one to be compliant.

Thanks for any help.  Todd
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KT0DD
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Posts: 353




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« Reply #1 on: June 20, 2015, 07:12:50 AM »

Well, I got the answer to my question from a friend who is a licensed professional commercial two way radio service person.

They have to be narrowband capable and locked by software to narrowband only on all Part 90 LMR frequencies. The VFO & keypad must be locked out on all Part 90 LMR frequencies as well to prevent accidental field programming.

The 2.5 kHz channel step is NOT a requirement so I guess the KG-UV2D is a legit accepted Part 90 rig.

Just posting this in case others need the info.  Thanks.
« Last Edit: June 21, 2015, 10:50:05 AM by KT0DD » Logged
W8JX
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Posts: 9329




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« Reply #2 on: June 21, 2015, 11:01:26 AM »

Given selectivity of FM rigs you cannot work two channels even 5 KHZ apart most off time so lack of 2.5khz steps is a moot issue anyway.
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You can embrace new computing technology and change with it or cling to past and fall further behind everyday....
KT0DD
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Posts: 353




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« Reply #3 on: June 21, 2015, 11:07:28 AM »

Yes, That is true. I wonder what's going to happen when the FCC goes to their 6.25 kHz mandate they are pondering. Everything will probably have to be digital modulation.

I like your quote at the end...However I prefer to be a Flintstone and not a Jetson...lol...I like K.I.S.S.
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KB8VUL
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« Reply #4 on: June 26, 2015, 09:15:55 PM »

OK, better and slightly more technical explanation.  The china funky bowel radios were part 90 under the old standard provided that the front panel programming was completely disabled by the programming software.  Remember that EVERY radio that was used as a Part 90 radio was type accepted at one time, even the ones that were not able to be narrowbanded.  There are several parts to getting type acceptance, not just the ability to transmit and receive at 2.5Khz deviation.  Spectral purity, frequency stability and broadband power are all part of the testing.  Now the broadband power applies more to the digital radios than the analog ones but I figure it needs to be mentioned.  The biggest issue was the frequency stability and a close second is the spectral purity.  When you half the deviation, you need 4 times the frequency stability.  With a 25Khz ham radio cranking out 5Khz of deviation, if you are off 500hz or even 1Khz you are still intelligible and are not going to cause near as much adjacent channel interference. With a narrowband radio, the channel spacing goes from 25Khz to 12.5 Khz.  And you drop the deviation of the radio from 5Khz to 2.5 Khz that 1Khz off frequency that was one fifth the total deviation is now over half the deviation and 500 hz is one fifth.  The radio needs to have a more stable frequency reference (costs more) than the radios of old.  It would do a prospective purchaser well to review the Part 90 documentation from the funky bowel radio as is is registered with the FCC and verify that the part 90 type acceptance is for narrow band radios as well as wide band. 
Remember that old versions of commercial radio software is out there.  You can obtain a commercial radio and program it for whatever including police/fire operations.  It's still not legal to do it, but it's physically possible if you know how.  And remember that if you have your HAM radio complete with VFO programmed up with commercial frequencies and are using them (no harm in monitoring if it will not transmit) you are not part 90 compliant regardless of what the little paper says in the box the radio came in.
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KB8VUL
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« Reply #5 on: July 02, 2015, 08:41:13 PM »

Given selectivity of FM rigs you cannot work two channels even 5 KHZ apart most off time so lack of 2.5khz steps is a moot issue anyway.


Holy Hell, he said something that was factual and even made sense.
Hate to admit it, but he's right. Ham gear is typically barn door wide in the front end.  This is due to them incorporating a DC to day light receiver.   If your hammie radio has more receive frequency range than a scanner (most do) then the selectivity on them is gonna be crap.  Back in the day, commercial radios used window filters in the front end of the radio to only allow the required range of frequencies in.  The filters were expensive, but very effective, just talk to anyone that converted a commercial UHF radio over to ham and they will tell yo it's a ton of work to keep them from being deaf as a post.  Selectivity and sensitivity go hand in hand.  If you have a barn door front end, signals several Mhz away can swamp the front end amplifiers and decrease the sensitivity.  Go look at the sensitivity numbers on a cheap commercial radio like a Motorola CP200 or old Kenwood 780 or 880 and then look at the same numbers on a ham radio or a scanner.  Commercial gear will be able to listen to a signal level of .19 microvolts.  A scanner is going to be around .28 to .35 which on a commercial radio would be totally unacceptable. The reason for the selectivity issues is ultimately cost.  If a ham radio cost what a commercial radio cost there would be fewer hams.  A base line Motorola mobile is gonna come in at $400 for a 4 channel radio with no display, and a total of 6 buttons on the front, 4 of them being the channel buttons.  For much less you can get a full VFO, 99 memory programmable ham radio.  The additional cost of the commercial radio is there for a reason.
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WA1MOW
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Posts: 16




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« Reply #6 on: July 29, 2015, 06:00:09 PM »

Yes, That is true. I wonder what's going to happen when the FCC goes to their 6.25 kHz mandate they are pondering. Everything will probably have to be digital modulation.

I like your quote at the end...However I prefer to be a Flintstone and not a Jetson...lol...I like K.I.S.S.

During the discussions about going to 12.5 Khz bandwith, (Narrow Band) the FCC said that they have no intention of going to 6.25 Khz anytime in the next 50 years. That was in 2001.
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KG4RRN
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« Reply #7 on: July 30, 2015, 08:27:58 AM »

I hate to throw water on the fire, but it seems that if you are operating Part 90 radio frequencies , you should be using Part 90 radios (which cost 2x more than ham radios.
They are made sturdier, and the reason is they get used in public service, they have to be strongly made.
I remember years ago, when they came out with patching consoles for All Communications
capable radios, in Mobile Radio Dispatch Vehicles (Red Cross Equivilent of ECRV's.
Ham radios today  (esp. Chinese flavor) would not stand up in a disaster situation.
I recommend ICOM  V-82 /U-82(which are no longer made) or Yeasu FT 60's for HT work.
Too bad there are no more AT-2, 202's or 404's (except at Hamfests).
The brick radios were strong-- and took a pounding.
The Chinese radios last 4-5 hrs and you have to replace the batteries.
There is alot to be said for older HT radios made between 1980 and 2000.
They lasted....
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WB8VLC
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Posts: 301




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« Reply #8 on: August 01, 2015, 08:49:33 AM »

You have to be kidding me, would you really use one of these spurious piece of crap plastic, disaster waiting to happen, handhelds for SAR use?

If you are serious about SAR use then do it the correct way and get a real Motorola or GE/MACOM radio, there are numerous NB compliant Motorola and GE/MACOM radios available for good prices on the used market.
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N9AOP
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Posts: 329




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« Reply #9 on: August 01, 2015, 11:33:13 AM »

Around here the only one pissed about us using the Chinese radios for SAR is the Motorola salesman. 
Art
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KB8VUL
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Posts: 193




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« Reply #10 on: August 03, 2015, 06:46:52 PM »

Around here the only one pissed about us using the Chinese radios for SAR is the Motorola salesman. 
Art


Motorola could care less.  If there was a real market for it, they would be producing radios to fill the need.
Fire radio's need to be intrinsically safe rated to be allowed to be carried by firemen.  Funky Bowel radios do NOT meet that spec.  Are there firemen using the Funky Bowel radios, sure.  Someone out there has to be somewhere.  But the first time they have one traced to causing a fatality due to it being an ignition source for a fire in an explosive gas environment then that will stop.  There are reasons that things cost what they do.  A Yugo had a 4 cylinder engine and a 4 speed transmission and would get you around.  Lotus also made a 4 cylinder 4 speed vehicle that would get you around but was much more expensive.  Car parts is car parts.  So why the huge difference in cost?  Cuz one was made WAY better. 
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N9AOP
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« Reply #11 on: August 05, 2015, 03:03:01 PM »

Yes for the fire service and no for the SAR
Art
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