RFI-EMI-GUY
Member
- Joined
- Dec 22, 2013
- Messages
- 6,877
With respect to the TR-505. This seems to be another case of a wonky dual service radio slipping past the "largely unwatching" eyes of the FCC OET. The FCC says they will no longer dual certify FRS, MURS and GMRS radios. I have some Motorola Systems Saber radios. These are certified for Part 95 GMRS and Part 90. They also do digital encryption which is a no no in GMRS. These radios were certified decades ago. They are legal today.
My opinions and observations of Cheap Chinese Radios;
I like to call them "low parts count radios" because that is what you are getting, for beer money. You must ask yourself why the Chinese can build a radio around a single IC chip when manufacturers like Motorola and Harris insist on putting hundreds of parts in their Part 90 radios. I can tell you the reason why, filtering at RF, IF and audio frequencies, a decent FM limiter to eliminate static and multipath pops, and compliance with industry minimum standards *.. You cannot put those passive and active parts inside a tiny slab of silicon. You can, do some fancy mathematics in DSP at IF and audio frequencies, but not with a $5 IC. Filtering the receiver front end and suppressing transmitter harmonics requires big expensive parts that you won't see in a $35 radio (or an overpriced CCR).
Then there are the "wonky" FCC certifications for these radios. The FCC only requires the radio to operate within certain spectrum masks for the modulation and harmonics. The FCC has no interest in whether the radio works well *. So lets say you are a Chinese manufacturer and you have a bunch of $5 transceiver chips and you want to turn them into radios to market them in the US. Instead of adding all those expensive filter parts that Motorola and Harris (and even Hytera) are obsessed with, you simply turn down the power and modulation until the radio passes under the spectrum mask. Who could possibly want to pay attention to the emission designation 5k6F3E or 10K3F3E? Just turn the mike gain up! Or that the radio must not be set to over 1.09616 watts or all hell breaks loose. You get what you pay for.
The new crop of radio enthusiasts seem to be obsessed with how cheaply they can buy a "radio", not with how well it will work in the real world. A lot like hypermilers who try to get 200 mpg even if it means removing all the seats and spare tires, tearing out the AC compressor and sliding through a few red lights.
*TIA603D defines MINIMUM performance specs for land mobile radios. Does your CCR comply with TIA603D ? Nope.
My opinions and observations of Cheap Chinese Radios;
I like to call them "low parts count radios" because that is what you are getting, for beer money. You must ask yourself why the Chinese can build a radio around a single IC chip when manufacturers like Motorola and Harris insist on putting hundreds of parts in their Part 90 radios. I can tell you the reason why, filtering at RF, IF and audio frequencies, a decent FM limiter to eliminate static and multipath pops, and compliance with industry minimum standards *.. You cannot put those passive and active parts inside a tiny slab of silicon. You can, do some fancy mathematics in DSP at IF and audio frequencies, but not with a $5 IC. Filtering the receiver front end and suppressing transmitter harmonics requires big expensive parts that you won't see in a $35 radio (or an overpriced CCR).
Then there are the "wonky" FCC certifications for these radios. The FCC only requires the radio to operate within certain spectrum masks for the modulation and harmonics. The FCC has no interest in whether the radio works well *. So lets say you are a Chinese manufacturer and you have a bunch of $5 transceiver chips and you want to turn them into radios to market them in the US. Instead of adding all those expensive filter parts that Motorola and Harris (and even Hytera) are obsessed with, you simply turn down the power and modulation until the radio passes under the spectrum mask. Who could possibly want to pay attention to the emission designation 5k6F3E or 10K3F3E? Just turn the mike gain up! Or that the radio must not be set to over 1.09616 watts or all hell breaks loose. You get what you pay for.
The new crop of radio enthusiasts seem to be obsessed with how cheaply they can buy a "radio", not with how well it will work in the real world. A lot like hypermilers who try to get 200 mpg even if it means removing all the seats and spare tires, tearing out the AC compressor and sliding through a few red lights.
*TIA603D defines MINIMUM performance specs for land mobile radios. Does your CCR comply with TIA603D ? Nope.
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