2 wrote:
>
>
>>2 wrote:
>>>An IR thermometer, a manometer, and some horse sense are more
>>>trustworthy than computer modeling -- i. e., if the thermometer says
>>>it's too damn hot, and the computer app says it's not, it is.
>>>
>>
>>They used to say that about antennas too, until MININEC and NEC became
>>available free to anyone who wants them. Certainly there are big
>>pitfalls in computer modeling, but antenna modeling has also shown that
>>"horse sense" isn't always reliable either. In the end, you need both,
>>in order to check each against the other.
>
>So if horse sense yagi-uda design -- i.e., tuning for max fwd gain on an
>antenna test range - with element length/spacing experimentation produces
>more gain than the computer modeling antenna, one should assume that the
>fault is with the test range ?
In all areas of engineering, professionals routinely do both modeling
and measurement, and use each to check the other.
Setting up modeling "versus" measurement, and turning it into an
argument, is strictly an amateur thing. It's time we grew out of it.
>>
>>
>>Exactly the same would apply to thermal/flow modeling if we had the
>>tools to try it.
>>
>>
>>Unfortunately IR thermometers are notoriously UNtrustworthy, unless they
>>are calibrated for emissivity and - for this application - also have a
>>very small spot measurement size.
>>
>The better ones have a light-beam guide spot.
>
The guide spot is a laser beam. The *sensing* spot can be an inch
across, or larger.
[...]
>Black shoe polish is not costly.
[...]
>Drill a hole, make the measurement, and tape the hole with aluminum tape.
I'd rather find better ways...
--
73 from Ian G3SEK Editor, 'The VHF/UHF DX Book'
'In Practice' columnist for RadCom (RSGB)
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