Kenwood TH-D72A Passes FCC Spur Limit

Posted on December 12, 2016 by robert

Running a spectral purity check on my Kenwood TH-D72A APRS radio, I found that it passes FCC requirements as you would hope it would.

The test setup used for the UV5R was only slightly modified to change the bandwidth so that the noise floor was lowered.  This uncovered a spur that is in the SA itself, at 344.8 MHz.  Since that is not coming from the UUT, it can be ignored.

The power from the TH-D72A was -3.66 dBm + 40 dB for the external attenuator = +36.34 dBm = 4.31 watts.

The worst case spur the fourth harmonic at -77.49 dBm, which (adding back the 40 dB from the external attenuator) is -37.49 dBm or 0.2 microwatts, a passing value.  It is also 73.8 dB below the carrier.

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BaoFeng UV82 Fails FCC Spur Limits

Posted on December 12, 2016 by robert

BaoFeng sells more radio models than you can shake a stick at.  Another handheld dual band unit that fails FCC spectral purity is the UV82.  This is somewhat larger than the UV5R, sells for a premium, but has an odd dual PTT button that confuses the heck out of users, as it will transmit on different channels depending on which PTT is pressed and how it is programmed.

The identical test setup used for the UV5R was used to test this radio, including the 100 KHz bandwidth setting.

The power from the UV82 was -3.87 dBm + 40 dB for the external attenuator = +36.13 dBm = 4.10 watts.

The worst case spur the third harmonic at -52.48 dBm, which (adding back the 40 dB from the external attenuator) is -12.48 dBm or 56.5 microwatts, a failing value.  It is also 48.6 dB below the carrier.

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Icom IC-80AD Spectral Purity

Posted on December 12, 2016 by robert

Running a spectral purity check on my Icom IC-80AD DSTAR radio, I found that it passes FCC requirements as you would hope it would.

The test setup used for the UV5R was only slightly modified to change the bandwidth so that the noise floor was lowered.  This uncovered a spur that is in the SA itself, at 344.8 MHz (#2 in the photo below).  Since that is not coming from the UUT, it can be ignored.

The power from the IC-80AD was -4.03 dBm + 40 dB for the external attenuator = +35.97 dBm = 3.95 watts.

The worst case spur the fourth harmonic at -74.51 dBm, which (adding back the 40 dB from the external attenuator) is -34.51 dBm or 0.4 microwatts.  It is also 70.1 dB below the carrier.

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Icom ID-51A+ Spectral Purity

Posted on December 12, 2016 by robert

Running a spectral purity check on my Icom ID-51A+ DSTAR radio, I found that it passes FCC requirements as you would hope it would.

The test setup used for the UV5R was only slightly modified to change the bandwidth so that the noise floor was lowered.  This uncovered a spur that is in the SA itself, at 344.8 MHz (#2 in the photo below).  Since that is not coming from the UUT, it can be ignored.

The power from the ID-51 was -3.48 dBm + 40 dB for the external attenuator = +36.52 dBm = 4.49 watts.

The worst case spur the third harmonic at -68.15 dBm, which (adding back the 40 dB from the external attenuator) is -28.15 dBm or 1.5 microwatts.  It is also 64.7 dB below the carrier.

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BaoFeng UV5R Spectral Purity Testing

Posted on December 9, 2016 by robert

I have seen some reports of BaoFeng radios not passing FCC Spurious Emission Standards.  I have a old UV5R that is affixed to my Fox Hunting RDF antenna.  I re-enabled the transmitter (normally programmed off to avoid accidentally blowing out the active elements of the RX-only RDF antenna) and tested it yesterday.

Executive Summary:  My particular UV5R fails the FCC 97.307(d) limit with a worst case spurious emission (3nd harmonic) of 53 µW.

FCC Limit: For a transmitter having a mean power of 25 W or less, the mean power of any spurious emission supplied to the antenna transmission line must not exceed 25  µW and must be at least 40 dB below the mean power of the fundamental emission, but need not be reduced below the power of 10 µW.

Test Setup:  UUT feeds a 40 dB Power Attenuator, the output of which is feeding a Siglent SSA3021X Spectrum Analyzer.  The SA calibration is valid through November of 2017.

Test Settings:  Start Freq 50 MHz, Stop Freq 600 MHz, RBW/VBW 100 KHz.  Input Power to SA was 40 – 3.74 dBm, or 36.26 dBm (4.23 watts).  Markers placed at fundamental, 2nd, 3rd, 4th harmonic.

Worst Case Spurious Emission:  The absolute power is -52.77 dBm + 40 dB = -12.77 dBm = 53 µW, which is a failing level.  The relative power is 49 dB below the carrier.

uv5r-test

As I mentioned before, my particular UV5R is pretty old, circa 2012.  Who know how newer units perform.

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Christmas Bunting QSO

Posted on December 4, 2016 by robert

I’m a little late getting the Christmas Tree lights installed on our pine trees in the back yard, but my friend John, WA1ABI, announced he was all ready with his tree lights, and expected to make a QSO with Rich, KC1ARO, today at 17:00 local time on 3.513 MHz

In desperation, I ran 150 feet of RG8X from my K3 onto our deck.  I had a 100 foot string of LED lights wrapped around a run of about 30 feet of deck railing — about 12-feet off the ground.  I took both leads of the lights and clip-leaded them to the center conductor of the coax.  The shield of the coax was attached to a 8-foot run of 1/2″ braid that was attached below the deck to my station ground (counterpose system of a 1/4 wavelength wire for 160m to 10m stapled to the house siding about 6 feet off the ground + three 8-foot ground rods).

I recorded a few seconds of both KC1ARO, and WA1ABI transmitting so their signal levels on the P3 and S-Meter could be seen.  After this I joined them both with some signals of my own.

John was S9 to S9+10 (MOV format): wa1abi

Rich was S5 to S7 (MOV format): kc1aro

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DXCC Standings at Beginning of Dec

Posted on December 2, 2016 by robert

I had a bit more time to spend on the air after the hustle/bustle of the Summer & Fall.  My DXCC Standings are as follows:

wb4son-dxcc-dec-2-2016

So over the last 3 months (September/October/November), I picked up two new countries fox my Mixed category, and eleven more band-countries toward my Challenge.  VERY slow progress.  At that rate I won’t hit 300 for another 3 to 4 years, about the same time that I will hit 1500 on the Challenge.   With solar activity declining, I want to shoot for DXCC on 160 meters.  Antenna work is underway.

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K1 Tuner Completed

Posted on November 30, 2016 by robert

It took about an hour to wind the 5 inductors and install the remaining components, so the entire kit took about 2.5 hours to assemble.  Some minor changes need to be made to the K1 itself, and the meter circuit needs to be calibrated.  I’d guess another hour.

img_5223

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Finally Building the K1 Antenna Tuner

Posted on November 20, 2016 by robert

I had a ball building my K1 Transceiver.  It has worked out very well, and has a fantastic receiver.  My only issue so far is that the transmit power folds-back aggressively.  If the SWR is high, the power will immediately drop back to 0.5 watts, remaining at that low level.  As a consequence, some of my automatic tuners will not work with the K1.  With that in mind, I purchased the internal tuner option earlier this year.

I finally started putting the kit together, which is very straight-forward.  With about 90 minutes into the process, I have all the parts except the inductors and connectors installed. As with all the Elecraft kits, the inductors need to be hand-wound.  These are pretty small/simple, so that’s not a big deal, but it will probably take me another 90 minutes to wind the 5 cores and install them.

k1at

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DX Surprise

Posted on November 14, 2016 by robert

After uploading my NPOTA log, I checked my confirmed contacts and was pleasantly surprised to find two ATNOs in the log:

wb4son-dx-surprise

TL8AO was an ATNO for me, and the LotW entry showed up within a few hours of our contact.  On the other hand, I’ve made dozens of contacts with Gibraltar on several bands.  ZB2TT just happens to be the only one to use LotW and confirm.  Thanks Bob!  My confirmed count improves to 257 (and 271 worked, so 14 still awaiting confirmation).

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