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Author Topic: Baofeng spectral purity (or lack thereof)  (Read 25147 times)
KJ7WC
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Posts: 81




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« on: October 17, 2015, 08:58:52 PM »

If you have not read the "ARRL Laboratory Handheld Transceiver Testing" article in the November 2015 issue of QST, I encourage you to do so.

How many of you have questioned the quality of Baofeng handhelds? Ever wonder what sort of signal is produced from a China-made radio that costs less than a steakhouse dinner? Well, of the four I've tested this week, all of 'em failed FCC compliance for Part 97.307e.

Here's one of the two UV-5Rs that I have at home:



I tested this UV-5R5 at a radio club meeting, this morning:



The test setup has 40dB of external attenuation, so the maximum allowable spurious emission (25 microWatts) is a -56dB reading. When driven at 5W output, both of the radios transmit over 200 microWatts (-47dBm +40dB) on one of its harmonics. My Baofengs are now reserved for receive-only.

What do you think should be done about these radios?
« Last Edit: October 17, 2015, 11:17:00 PM by KJ7WC » Logged
SOFAR
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Posts: 1473




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« Reply #1 on: October 18, 2015, 01:05:18 AM »

Eh, I was never a fan, don't own one.  And some people actually  make direct comparisons to Yaesu, Icom etc.

Why don't you lead us off.. What should be done?
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WB4SPT
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Posts: 777




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« Reply #2 on: October 18, 2015, 04:12:56 AM »

These both are tx mode? Did you filter the carrier with a high pass?  RU sure the analyzer is still linear?   
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NK7Z
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« Reply #3 on: October 18, 2015, 04:57:00 AM »

These both are tx mode? Did you filter the carrier with a high pass?  RU sure the analyzer is still linear?   
Hi,
If the levels are low, and the analyzer is still in it's linear range, what is the need for the High Pass filter?
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Thanks,
Dave
Amateur Radio: RFI help, Reviews, Setup information, and more...
https://www.nk7z.net
KJ7WC
Member

Posts: 81




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« Reply #4 on: October 18, 2015, 09:47:12 AM »

The analyzer was purchased within the last two months, and total input was padded to -3dBm (well below the maximum of +20dBm). Right after I measured the UV-5R5, I put a Yaesu handheld on the unit which measured well within compliance. I am confident in the results that I shared in the opening post.

I would stop importation of radios that are non-compliant. If there are no FCC type acceptance certificates on file, and the radios fail the emissions standards specified in 97.307, then they have no purpose in the United States. Since I am but one amateur radio operator, the purpose of this thread is to make all of you aware of the issue and allow an open discussion of the situation.
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WA2ISE
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Posts: 1290




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« Reply #5 on: October 18, 2015, 01:36:58 PM »

Maybe the Baofeng radios can tell when they are in an FCC test lab?   Grin
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NO2A
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Posts: 1400




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« Reply #6 on: October 18, 2015, 01:57:40 PM »

Thanks for the info. Appreciate it.
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KJ7WC
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Posts: 81




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« Reply #7 on: October 18, 2015, 02:06:34 PM »

Just to keep things fair, here's the aforementioned Yaesu VX-7R:



Maybe the Baofeng radios can tell when they are in an FCC test lab?   ;D

Given recent events, it's a welcomed bit of humor. :o)
« Last Edit: October 18, 2015, 02:08:43 PM by KJ7WC » Logged
WB4SPT
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Posts: 777




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« Reply #8 on: October 18, 2015, 03:13:39 PM »

The analyzer was purchased within the last two months, and total input was padded to -3dBm (well below the maximum of +20dBm). Right after I measured the UV-5R5, I put a Yaesu handheld on the unit which measured well within compliance. I am confident in the results that I shared in the opening post.

I would stop importation of radios that are non-compliant. If there are no FCC type acceptance certificates on file, and the radios fail the emissions standards specified in 97.307, then they have no purpose in the United States. Since I am but one amateur radio operator, the purpose of this thread is to make all of you aware of the issue and allow an open discussion of the situation.

Agree with philosophy. I do compliance testing.  My point is to make sure analyzer is not contributing to your harmonics.  It's not overload of the front end .  Anyway its a simple test.  Just add 10db more atten and see if you numbers track.
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KJ7WC
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Posts: 81




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« Reply #9 on: October 18, 2015, 04:13:59 PM »

With another 10dB of pad, the trace math function showed between 9.8dB and 10.9dB additional attenuation. I think it's safe to say that the harmonics shown on these plots are from the radios. If I can figure out how to apply the peak table to the math trace, I'll run the test again and post the results.
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WB4SPT
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Posts: 777




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« Reply #10 on: October 18, 2015, 10:07:54 PM »

Excellent. I'm in s. china now on business.  Where is this bofang factory
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W2NAP
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Posts: 290




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« Reply #11 on: October 18, 2015, 11:33:38 PM »



I would stop importation of radios that are non-compliant. If there are no FCC type acceptance certificates on file, and the radios fail the emissions standards specified in 97.307, then they have no purpose in the United States. Since I am but one amateur radio operator, the purpose of this thread is to make all of you aware of the issue and allow an open discussion of the situation.

got to remember to those galaxy,superstar,ect.ect "10 meter" export cb radios ain't to be sold in the USA yet thousands sell every year.

fcc lost the chance to nip it in the bud when they allowed the 1st ones on shore without checking them out. add in amazon and others selling them as cb radios and such. great problems happen..

I get to thank amazon for selling a baofeng locally to an unlicensed person who has been bootleggin on my repeater, but thats another story.
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I AM THE VOICE OF THE VOICELESS!
KJ7WC
Member

Posts: 81




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« Reply #12 on: October 18, 2015, 11:46:31 PM »

Actually, I have no historical knowledge of CB radios and their illegitimate cousins. I am simply aware of the omission of input filters for 10/12m with domestic amplifiers.

Terrible shame about the QRM on your repeater, Tony.
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N6BIZ
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Posts: 30




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« Reply #13 on: October 20, 2015, 08:34:10 AM »

NOBODY CARES
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KJ7WC
Member

Posts: 81




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« Reply #14 on: October 20, 2015, 07:47:18 PM »

NOBODY CARES

Normally I wouldn't respond to such nonsense, but I'll entertain it this time. In order for CFR Title 47 Part 97A Section 307 to exist, someone cared enough to assess acceptable levels of spurious emissions, formulate a set of rules, and put forth both the time and effort to carry those proposed standards through a bureaucratic ratification process. If nobody cares about an extra 10dB of spurious emissions from a handheld, then why should they care about 20dB? How about 30dB? Would you care if your neighbor were using a 5W transmitter on 2m that spewed 50mW of garbage on the same 70cm frequency that serves as output to your favorite repeater? Just remember that they are the same rules that you committed to when the FCC granted permission for you to transmit on the amateur radio bands.

Folks, my main radio is a Yaesu FT-897D. In case you missed the VX-7R on an earlier post, here's the FT-897D transmitting 50W on 2m:



To put it into perspective, the 5W Baofeng UV-5R5 that I tested is 20 times dirtier on 70cm, whilst transmitting 1/10th of the power on its fundamental!
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