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#61 mire

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Posted 02 October 2020 - 01:45 AM

I wouldn't say they "squatted", but more like the FCC ignored the illegal operation to the point of no return.


Pretty much amounts tp different ways of saying potato. Some never bothered to read the package, some read it and ignored it, and you’ll also on occasion run into people who think that, if they squat enough, we’ll end up with license-by-rule UHF CB, repeaters and all.

In fact you could say the FCC screwed up by commingling FRS and GMRS together by allowing dual service radios in the first place.


That’s exactly what I say.
 

It's really no different than the old CB radios days when so many people got radios and skipped getting the license. After a while the FCC gave up and made 11M effectively license free. They made their problem go away by making the unlicensed illegal operation now legal.


And I feel there’s a segment of the population which wants to do that on UHF. They’re already most of the way there - all that’s left is the repeater inputs and use of repeaters. Not that I really think anyone aside from a limited number of those with garage repeaters would keep their towers up without switching to 70cm if that were to happen,
 

Oh, about a restaurant employee demanding you get off "his channel", well go look for videos and stories about Walmart and MURS. Seems like some of those places think they own those frequencies too. Don't forget that MURS is open to various uses including wireless intercoms, digital data etc. You'll have that to look forward to as well when more people start using it.


Yeah, I know about Walmart and MURS. And it kinda was hidden in the shadows for some time. People of course knew at least something about FRS and GMRS, but MURS really took off more in maybe the last 8 years or so, especially once BaoFeng radios began entering the scene (amd people didn’t know, didn’t care to know, or just plain didn’t care about the illegal nature of using those radios outside of Part 97).

Just an additional question was that a GMRS frequency, 462.650/467.650 with a tone of 151.4? It wasn't exactly clear to me when i read it the first time around. The frequency 151.4 looked like a typo for one of the three MURS channels in the 151 MHz range.


The confusion was my doing. Yes… almost. I was running simplex, so no 467.650. Our repeaters on Front Range GMRS use non-standard DCS octals, so we haven’t run into problems there when using the repeater. Though once in a while I do get interference from a closer blister pack user on the same channel with a different DPL tone. That pisses me off. Yes, I understand it’s legal for them to use it now, but only because they squatted on those channels in the first place. I really find it hard to believe that the FCC couldn’t anticipate what was going to happen when they gave type acceptance to these 22 channel blister pack radios, and I think any semblance of the Open Repeater Initiative will eventually be killed off both by the BaoFeng crowd who think they can buy those radios and transmit freely wherever they want (just look at the questions and answers and reviews on Amazon pages for those products), not to mention now you’ve got Jeep pushing the Midland GMRS radios.
2x Kenwood TK-3180
3x Kenwood TK-380
Motorola HT750
Kenwood TK-3700
3x Kenwood TK-350G
Kenwood TK-353G
A whole slew of BaoFeng BF-888S and GT1 radios
Kenwood TK-880
Kenwood TK-890
Kenwood TK-8360

#62 Hans

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Posted 02 October 2020 - 03:04 AM

Many valid gripes here but things are as they are now. We all have to figure out how to use FRS, GMRS, and MURS in harmony. Anyone that can't perhaps isn't well served by those three personal radio services. For them, there are amateur and commercial radio services as well as the 900 MHz license by rule service (I forget what its called).

If many high profile repeaters did move to 70 cm, I wouldn't lose a lot of sleep. In metropolitan areas, a lot of high profile repeaters use up a limited number of repeater pairs and may add to the friction. I respect and work with those who have high profile systems. I welcome them and am glad they are there; they have every right to be. However, when a population dense area gets saturated with them, it pushes too many out from using GMRS fully. Low profile, some call "garage repeaters", better fit the modern GMRS model. I think a mixture of a few high profile and a lot of lower profile repeaters is a more equitable and genuine model for GMRS.



#63 Lscott

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Posted 02 October 2020 - 06:26 PM

Many valid gripes here but things are as they are now. We all have to figure out how to use FRS, GMRS, and MURS in harmony. Anyone that can't perhaps isn't well served by those three personal radio services. For them, there are amateur and commercial radio services as well as the 900 MHz license by rule service (I forget what its called).

 

I think you're referring to the ISM frequencies. Motorola sells 50 channel digital radios for this unlicensed service.

 

https://www.motorola...#tabproductinfo

 

Here is the brochure for them. They can do 1 watt.

 

https://www.motorola..._spec_sheet.pdf

 

If they aren't too expensive they could be fun to get a couple to play with.


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#64 Lscott

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Posted 02 October 2020 - 06:41 PM

There is a far cheaper analog radio to look at also for the 900MHz ISM band.

 

https://www.retevis....-Two-Way-Radio/


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#65 n1das

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Posted 02 October 2020 - 09:58 PM

There is a far cheaper analog radio to look at also for the 900MHz ISM band.

 

https://www.retevis....-Two-Way-Radio/

 

This radio is Vaporware and not cheaper.  The specs posted on Retevis' site contain many red flags (can you spot them all?) and contain conflicting and mutually exclusive information.  The published specs resemble a hilarious copy and paste of specs from multiple sources.  Epic FAIL.  The minimum order quantity (MOQ) is 200 at $60 each ($12k total).  I posted about this radio in the RadioReference.com forums.

https://forums.radio...e-radio.413954/

 

I own a small fleet of Motorola DTR700 portables and a small fleet of DTR650 portables.  I previously owned a small fleet of DLR1060 radios which I later sold to a friend of mine for his business.  At first he wasn't sure what he was going to do with them except may use them for radio rentals.  Now he and his employees use them all the time around the office and at job sites because they work so well.

 

Don't underestimate a FHSS digital radio on 900MHz just because of the 1W transmitter power. My range record with a pair of 900MHz Motorola DTR650 FHSS digital portables transmitting at 890mW (+29.5dBm) stands at 12 miles from the Cocoa Beach Pier in Cocoa Beach FL to the top of the steps from the parking lot leading down to Hightower Beach in Satellite Beach FL. The top of the steps are about 30 ft or so above sea level. There is a bit of coastline in the way so it's not entirely line of site. Myself and a friend of mine who helped me test the DTRs also had 4W UHF Part 90 portables with us which we had on GMRS to compare to. (We are both GMRS licensed.) We were able to communicate on GMRS simplex but the received signal strength was noisy and scratchy and we each had to find a hot spot and stay there in order to communicate. The DTRs were crystal clear because of the digital modulation and overall was more reliable and finding a hot spot for them was less critical.

Motorola DTRs on 900MHz are capable of outperforming VHF and UHF conventional portables on simplex. Where the DTRs beat VHF and UHF conventional portables is when operating inside buildings due to buildings being much more open at 900MHz compared to 150MHz and 450MHz. Where the 900MHz DTRs blow all others away on simplex is when operating aboard cruise ships. People who have used DTRs aboard cruise ships report having full ship coverage on all decks compared to a pair of 4W UHF portables on GMRS simplex which had trouble penetrating more than about 2 decks. When operating aboard a cruise ship, you are essentially operating inside a compartmentalized metal box. The shorter wavelength signals at 900MHz reflect in an out of the many nooks and crannies of the ship where longer wavelength signals at VHF and UHF won't. The many reflections actually help with the FHSS operation because individual hot spots and dead spots also hop around as the frequency hops. The FHSS operation effectively stirs the modes so to speak.

I never got my DTRs to set any range records.  I got them for reliable local on-site simplex type use with family and friends.  They are my high quality professional digital replacement for GMRS/FRS and MURS for local simplex type use.  They outperform UHF Part 90/95 conventional portables on simplex and totally blow FRS away.  A coworker once asked me why not just use FRS? My answer was that I have already been doing that since FRS was created in 1996 and longer than that as a GMRS licensee since 1992 with Part 90/95 commercial gear. I want a secure, high quality digital solution that is higher quality and more professional than FRS. The fact that they are totally scanner proof comes as a bonus. They are not monitorable on any consumer grade receiver (scanner) so don't even bother trying.

 

I hardly use GMRS/FRS at all any more because I migrated my local on-site simplex type use with family and friends to the DTR radios on 900MHz.


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David Sterrett, N1DAS

Nashua, NH, USA

Ham [HA] = N1DAS (2/1984)

GMRS [ZA] = KAE9013 (12/1992)

 


#66 n1das

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Posted 02 October 2020 - 10:15 PM

There is a billiards club about 2 miles from my location and almost direct line of site and employees use GMRS/FRS on 462.725MHz simplex with DPL252.  The little bit of chatter I've heard sounds like security and/or bouncers.

 

What caught my attention was that D252 is one of the standard 104 DCS/DPL codes but is not one of Motorola's original set of 83 standard DPL codes which are a subset of the 104 codes.  Most FRS radios advertise "121 codes" consisting of the 38 standard CTCSS/PL tones plus Motorola's original set of 83 DCS/DPL codes.  It makes me wonder what equipment they are using, either Part 90 commercial gear or one of the newer FRS models advertising "142 codes" (38 CTCSS/PL + 104 DCS/DPL).

 

http://onfreq.com/syntorx/dcs.html


David Sterrett, N1DAS

Nashua, NH, USA

Ham [HA] = N1DAS (2/1984)

GMRS [ZA] = KAE9013 (12/1992)

 


#67 Lscott

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Posted 03 October 2020 - 12:43 AM


 

I hardly use GMRS/FRS at all any more because I migrated my local on-site simplex type use with family and friends to the DTR radios on 900MHz.

Yes I saw the MOQ number. That doesn't imply you can't buy them in single units from a vendor somewhere. The point of the exercise is there are radios available for the 900MHz ISM band. If somebody really wants one they can do the searching for a vendor.

 

Everyone makes errors in their spec's, or the real engineering spec's changed after the original spec's were published. Some just do a better job of making far fewer errors in the published spec's or feature lists.

 

There are other license free radio bands in the US. Some people have been experimenting on 49 MHz to 50 MHz, right below the Ham 6M band. Power is limited to 100 milliwatts.

 

https://www.qsl.net/49mhz/

 

One other thing to point out is the 900 MHz ISM band is also the Ham 33cm band so you have to share it, and with old cordless phones and the other junk you find on it.

 

https://en.wikipedia...centimeter_band

 

https://w6aer.com/ge...00mhz-ham-band/


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#68 mire

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Posted 03 October 2020 - 01:46 AM

In metropolitan areas, a lot of high profile repeaters use up a limited number of repeater pairs and may add to the friction. I respect and work with those who have high profile systems. I welcome them and am glad they are there; they have every right to be. However, when a population dense area gets saturated with them, it pushes too many out from using GMRS fully. Low profile, some call "garage repeaters", better fit the modern GMRS model. I think a mixture of a few high profile and a lot of lower profile repeaters is a more equitable and genuine model for GMRS.


Is over saturation of repeaters really a thing, though? I don’t really get the impression there’s an abundance of them. Here in the Denver !etro, we have five, with one currently down for repair and another being a private repeater used by a group of local hams for rag chew. Looking through the list, NYC is really the place where this conflict might exist. I can certainly see potential problems with it, but not that high a likelihood. Even if GMRS did fully go license by rule, I don’t really anticipate it would lead to a flood of low profile repeaters. Even if you look at the intentional squatters thinking it’ll lead to UHF CB, they don’t actually want to put repeaters up themselves, for the most part, and those who do want them tend to want portables to bring on camping trips and such.
2x Kenwood TK-3180
3x Kenwood TK-380
Motorola HT750
Kenwood TK-3700
3x Kenwood TK-350G
Kenwood TK-353G
A whole slew of BaoFeng BF-888S and GT1 radios
Kenwood TK-880
Kenwood TK-890
Kenwood TK-8360

#69 Hans

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Posted 03 October 2020 - 02:05 AM

Is over saturation of repeaters really a thing, though? I don’t really get the impression there’s an abundance of them. Here in the Denver !etro, we have five, with one currently down for repair and another being a private repeater used by a group of local hams for rag chew. Looking through the list, NYC is really the place where this conflict might exist. I can certainly see potential problems with it, but not that high a likelihood. Even if GMRS did fully go license by rule, I don’t really anticipate it would lead to a flood of low profile repeaters. Even if you look at the intentional squatters thinking it’ll lead to UHF CB, they don’t actually want to put repeaters up themselves, for the most part, and those who do want them tend to want portables to bring on camping trips and such.

Yes, in my AO we are scraping to find repeater pairs for repeaters. We have several very high profile repeaters and it takes careful consideration for each new low profile on that goes on air. Thankfully, all repeater owners in our area have cooperated in figuring out what pair will work best for a given site. More low profile repeaters and one higher profile repeater are planned in the next couple of months



#70 n1das

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Posted 04 October 2020 - 02:09 AM


 

Everyone makes errors in their spec's, or the real engineering spec's changed after the original spec's were published. Some just do a better job of making far fewer errors in the published spec's or feature lists.

 

There are other license free radio bands in the US. Some people have been experimenting on 49 MHz to 50 MHz, right below the Ham 6M band. Power is limited to 100 milliwatts.

 

https://www.qsl.net/49mhz/

 

One other thing to point out is the 900 MHz ISM band is also the Ham 33cm band so you have to share it, and with old cordless phones and the other junk you find on it.

 

https://en.wikipedia...centimeter_band

 

https://w6aer.com/ge...00mhz-ham-band/

 

 

The errors in the specs for the Retevis 900MHz radio isn't just a simple mistake or two.  Many of the specs are incorrect and N/A for a FHSS radio.

 

Here's some fact checking....blue text is mine.

 

Overview on Retevis' website:

Licensed by the Federal Communications Commission (FCC) and Industry Canada to operate in the license-free 900 MHz ISM (Industrial, Scientific and Medical) band.

Okayyyy.....

 

 

Designed for business operations, the DTR Series radio will free your time from regulatory paperwork and licensing applications and saving radio licensing fees.

 

Are we talking about a Motorola DTR 900MHz FHSS digital radio or a Retevis 900MHz FHSS radio?  The statement looks like a copy and paste from Motorola's documentation.

 

 

Features:

1. 900MHz FHSS license free radio

2. Digital and analog compatible

Support DMR digital and analog two communication modes to ensure that the original analog products smooth transition to digital products to meet different communication needs

 

FALSE.  Can't be both of these at the same time.  An FHSS radio is not compatible at all with a conventional analog or digital radio.  An FHSS radio won't use DMR either.

 

 

3. Digital signaling function

Rich calling modes that support DMR protocol, including single call, group call and all call; supports remote inhibit function and other applications
 

FALSE.  It won't be using DMR if it's an FHSS radio.

 

 

4. Interference free, private communications

Leverage Frequency Hopping Spread Spectrum (FHSS) technology for more reliable and private communication when compared to standard analog radios.

 

This is TRUE!

 

5. High sound quality

This digital two-way radio uses advanced AMBE +2TM voice processing technology to achieve higher quality

 

PARTIALLY TRUE.  The digital audio from a Motorola DTR radio and other digital radios is high quality.  The AMBE+2 vocoder is for a DMR conventional radio, not for an FHSS digital radio.  The Motorola DTRs use Motorola's VSELP vocoder.  VSELP was used in Motorola ASTRO digital radios before P25 Phase 1 which uses the IMBE vocoder.  VSELP was also used by iDEN phones on NEXTEL and other iDEN networks.

 

6. Prominent functional keys

Programmable button can be used to quickly access call features like Call All/Page All, to talk to radios without searching through your channel list.[/quote]

 

The Call All/Page All refers to the Call All Available and Page All Available features in the Motorola DTR600/700 radios and Motorola DLR1020/1060 radios.  The legacy DTR410/550/650 models (now discontinued) don't have the Call All/Page All features.

 

7. Supports the use of repeater

 

PARTIALLY true.  FHSS radios such as the Motorola DTRs are simplex only and occupy the entire 902-928MHz band when they transmit.  There is a repeater available for them ($1500) but it does not function like a conventional repeater.  It consists of a pair of DTR radios running custom firmware and a controller to behave as a repeater.  Each DTR radio uses a different frequency hopset.  DTR radios talking on one hopset can talk to DTR radios on the other hopset using the repeater, and vice versa.  It is one way operation at a time.  The repeater has to be carefully placed to extend coverage areas.  It is usually located where there is some overlap between an existing coverage area and the desired extended coverage area.  The application for this is to extend coverage areas inside large buildings.

 

Some on-site business systems use the 900MHz band, including the Motorola DTR 900MHz FHSS frequency hopping spread spectrum handheld radios, which operate at 1watt ERP transmit power on the 902-928MHz ISM band using frequency hopping digital voice. Current examples include the Motorola DTR600 and DTR700 radios, These radios operate with 50kHz channel spacing and 8-level FSK digital FHSS. 902.525MHz to 927.475MHz coverage.

 

Mostly true.  This statement reads like marketing literature.  An FHSS device operating in the 902-928MHz band is required by FCC 15.247 to use a minimum hopset of 50 frequencies and with a maximum output power of 1 W (+30 dBm).  The Motorola DTRs operate at 830mW (+29.2 dBm) to 890mW (+29.5 dBm).  The measurement of transmitter output power is a conducted measurement made at the antenna connector.  Output power is not specified in terms of ERP or EIRP.

 

The 50kHz channel spacing refers to individual frequencies in adjacent hopsets, NOT individual frequencies within a given hopset.  The Motorola DTRs have 10 hopsets available, consisting of 50 individual frequencies, spaced 500 kHz apart.  The 902-928MHz band has 26MHz of spectrum and gives 52 frequencies spaced 500kHz apart.  The first and last frequency is not used due to being at the band edges so that leaves 50 frequencies available in a hopset.  Frequencies in adjacent hopsets are offset by 50kHz.  The spec'd 902.525MHz to 927.475MHz coverage is correct for the Motorola DTRs.

 

The mention of the 8-level FSK digital modulation for the FHSS operation is correct for the Motorola DTRs and refers to the modulation used on each hopping frequency.  The occupied bandwidth of the 8-level FSK modulation on a given hopping frequency is wider than what a narrowband receiver will accept, even if you were to stop the FHSS and have the transmitter sit on a single frequency. 

 

 

Technical specs on Retevis' website: A mixture of DTR, DMR, and analog specs (LOL). At least they got the DTR freq range right!
 

Main technological specification
 


Frequency range​

902.525 - 927.475 MHz​

Channel Capacity​

30/50CH (up to 200)​

Channel Spacing​

25KHz/12.5KHz​

Operating Temperature​

-25℃~+60℃​

Operating Voltage​

DC 3.7V​

Antenna Impedance​

50Ω​

Microphone Impedance​

2.2KΩ​

Battery​

1800mAh​

Dimension​

128×54×32mm

(No including antenna)​

Weight​

223g​

 

Freq range:  Correct for the Motorola DTRs.

 

Channel capacity:  Channels in the Motorola DTRs refer the number of public talkgroups or Profile ID talkgroups that can be programmed.  The "up to 200" refers to the maximum number of private contacts that can be programmed for setting up private talkgroups and for private 1 to 1 calling.  This is NOT the RF channel capacity like in a conventional radio.

 

Channel spacing:  Incorrect.  This is the channel spacing for conventional analog and digital radios in wide and narrow bandwidths and is N/A for an FHSS radio.

 

Transmission
 


Output power​

1W​

FM modulation​

25/16K¢F3E 12.5K/8K¢F3E​

4FSK digital modulation​

12.5KHz for data:7K60FXD 12.5KHz for data and voice :7K60FXE​

Vocoder type​

AMBE++or SELP​

Digital Protocol​

ETSI-TS102 361-1,-2,​

Harmonic​

≥70dB​

Signal-to-noise Radio(wide/narrow)​

25K≤-45 dB

12.5≤-40 dB​

Rated audio Distortion​

≥5%​

Frequency Stability​

±2.5ppm​

Max Frequency Stability​

12.5K≤-40dB​

 

Output power:  Correct.

 

FM modulation:  Incorrect and refers to conventional and analog radios.  N/A for FHSS digital radios.

 

4FSK digital modulation:  Incorrect.  Refers to DMR digital modulation for conventional radios.  N/A for FHSS and the Motorola DTRs which use an 8-level FSK modulation scheme on each frequency in a hopset.

 

Vocoder type:  Incorrect.  AMBE++ is used by DMR.  SELP = ?  The Motorola DTRs use Motorola's VSELP vocoder.

 

Digital Protocol:  Incorrect.  The ETSI standard listed is for DMR.  N/A for FHSS analog or digital.

 

SNR (wide/narrow):  Incorrect and N/A for FHSS.  The spec is for conventional radios.

Reception
 


Sensitivity (12dB SINAD)​

Analog 25K≤-121dB 12.5K≤-119dB​

Digital 0.3μV/BER5%​

 
Signal-to-noise Radio​

25K≥45 dB 12.5K≥40dB​

Adjacent channel selectivity​

25K≥65 dB 12.5K≥60dB​

Intermediation (Wide/ narrow)​

25K≥60 dB 12.5K≥55dB​

Spurious Response Rejection​

≥65 dB​

Audio power​

1W​

Audio distortion​

<5%​

Frequency Stability​

±2.5ppm​

Battery life under 5-5-90duty​

14.8 hours(with 1600mAh Li-ion battery)​

20.9 hours(with 1600mAh Li-ion battery)​

 

 

Sensitivity:  Incorrect.  The spec listed is for conventional wide/narrow operation.  N/A for FHSS.

 

SNR:   Incorrect.  The spec listed is for conventional wide/narrow operation.  N/A for FHSS.

 

Adjacent channel selectivity:  Incorrect.  The spec listed is for conventional wide/narrow operation.  N/A for FHSS.

 

Intermodulation  (intermediation LOL):  Incorrect.  The spec listed is for conventional wide/narrow operation.  N/A for FHSS.

 

Spurious Response rejection:  N/A for FHSS.

 

The Bottom line:  EPIC FAIL.  Too many glaring mistakes with specs which are N/A and incompatible with FHSS operation.  I have to call BS here and say this radio is Vaporware.

 

There were some analog 900MHz FHSS radios made by TriSquare a number of years ago.  These were the eXRS radios and were marketed as an alternative to FRS.  They operated on 900MHz and used FHSS.  The similarities with the Motorola DTR radios ended there.  The eXRS radios were analog and used a hopset of 50 frequencies per FCC 15.247.  They spent 400ms on each frequency in the hopset, the maximum accumulated dwell time allowed per FCC 15.247.  This meant they hopped very slowly and you could sort of monitor them with a scanner if it was fast enough and only scanning the specific freqs in the hopset.  Using a divide and conquer approach by employing multiple scanners with each scanner covering a portion of the hopset worked better.  You would hear the audio ping pong between multiple scanners but at least you could sort of monitor the eXRS radios.  The eXRS radios were notorious for synchronization problems and took a long time to re-sync if synchronization was lost.  The bottom line is these radios were total JUNK and the company is out of business.  OTOH, the Motorola DTRs are professional quality and 100% digital and packed with features and work amazingly well.  The DTRs spend no more than 90ms on any given hopping frequency, which works out to around 11 hops/second.  The fact that the DTRs are completely scanner proof comes as a bonus.

 
 

I have been on the 902-928 band on 33 cm ham repeaters.  The Motorola DTRs operate perfectly fine and coexist with everything else transmitting in the 902-928MHz band.  The FHSS operation allows them to peacefully coexist with everything else in the band without interference. Unlike conventional radios they are VERY difficult to jam due to the FHSS operation.


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David Sterrett, N1DAS

Nashua, NH, USA

Ham [HA] = N1DAS (2/1984)

GMRS [ZA] = KAE9013 (12/1992)

 


#71 Lscott

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Posted 04 October 2020 - 12:20 PM

The real question is are the radios being sold in the US? If so what is the FCC ID. With that in hand checking the FCC certification test report would be the definitive answer to radio’s operation. In the case above it looks like somebody did a particularly bad job writhing up the spec’s.

 

Again mistakes in the spec’s doesn’t mean the radio doesn’t exist, or will soon. I ran across a brochure for a Kenwood commercial radio that claims an FCC certification it does not have. Even the company I work for get spec’s wrong. Our sales manager ran a full page color glossy ad on the back cover of a very well known trade magazine years ago with a glaring error that almost got her fired when the company president found out. That happened because nobody from the engineering department reviewed it for accuracy before publishing it. 






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