I've been researching components to use in constructing
a software defined radio and when specifications are
given, there is a circuit diagram, board layout as tested,
bill of materials so you know specs on filter caps, inductors,
etc. along with the manufacturers part numbers for those
components, test equipment model numbers, and setup diagrams
for each test.
I can see not including this in a magazine article, but a URL
to the information doesn't take much space...TenTec could include
at their web site...
This would give us some real hairs to split ;-)
73, Bob
ah7i
Jim Reid wrote:
>Hmmmm........
>
>The ARRL lab came out with IP's well below the
>Ten Tec specs; seems odd. TT spec is +4 dBm for
>the third order IM intercept point, at least that is what
>the ARRL lab test reports TT has specified.
>
>At 3.5 MHz, 20 kHz signal spacing, the ARRL claims to
>have measured only -4.5 dBm; and at 14.2 MHz, only -3.4 dBm.
>Those are really significantly lower numbers than the allleged
>Ten Tec claimed spec. And, for 5 kHz signal spacing, the
>deltas are even greater: 3.5 MHz, ARRL says -30 dBm;
>and for 14.2 MHz, -29 dBm. Those are huge differences
>IF TT really specs +4 dBm IP3 for the tested spacings
>by the ARRL labs.
>
>Also, TT, they say, specs the second order IP to be +66 dBm.
>But the ARRL lab reports only +47 dBm. Again, a very large
>difference.
>
>No mention seems to occur about these deltas in the verbose text
>by the reviewer about the rig; his only comment, "The third-
>order intercept was in the negative numbers..........".
>
>Wonder how the engineering team at Ten Tec, and the techs
>in the ARRL labs are doing things differently to arrive at such
>diverse test results? I don't believe the Argo V has an RF
>preamp which can be turned ON/OFF. If it does, then the IPs
>will change by the gain of the preamp; they will drop about the
>same as the preamp gain IF the spec as given, is with
>the preamp OFF. Note there is an Attenuator button on this
>Argo, does it turn off a preamp, or actually insert loss?
>Was the Attenuator ON or OFF for the tests; what is the
>intended Ten Tec setting of the Attenuator for their claimed
>+4 dBm 3rd order IP and +66 dBm 2nd order IP?
>
>Oh well, some explanation will come along from someone,
>I am sure.
>
>73, Jim KH7M
>
>
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