OK, so it's not top of the range HP kit but it should be good enough to give an indication of problems with emissions from a faulty transmitter or feed system.
Basically, the TalkPCR software sweeps the scanner up the frequency range while reading an output which has been accurately calibrated in firmware at the factory. Range, steps, and rates are up to you...
|Shown above is a scan from 10MHz to 100MHz using the supplied antenna and with the -20dB attenuator switched in. I have my suspicions that this get less and less effective as you drop below 100MHz which will distort the results. Over on the right hand side, a crop of radio stations at approx -90dB. I may be wrong, but I'm guessing the hump around 33MHz and hash at 66MHz is coming from the PC....|
|This is a plot of the FT-101E @ 25W output fixed carrier on 14.150MHz. The transmitting antenna feedpoint is about 10m from the PCR-1000 receiving antenna. Note that the 3rd harmonic is only about 10dB higher than the rubbish put out by the PC at a distance of 1.5 metres.|
|The FT-990 at the same power output. Note that the second harmonic is reduced compared to the FT-101, as would be expected from a push-pull output stage.|
|Bearing in mind that the results are likely to be distorted by the poor receiving antenna to make the fundamental look a lot lower than it really is, it's good to see the harmonic distortion performance from the FT-990 being comparable to a valve TX. As solid state boxes go (and 12V ones at that), this is a nice clean TX.|
|When I get round to making up some attenuators, I'll run the tests again connecting the PCR-1000 direct to the TX for some proper plots without all the rubbish cluttering them up.|
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