SV: XV144 state of the art or ... Test of the Large SignalBehaviour of some 144 MHz Radios?

[Samir Popaja]

Why I put this on the reflector?

I'm in processing to buy transverter, which I will use "to begin" with ts-850s, then maybe with K2, which I think is "perfect" portable combo for VHF contesting.

After reading this test I was little bit scared and want the Elecraft community (owners of XV144) to make little positive comments on XV144.

Thank You
73' SM7VZX

-----Ursprungligt meddelande-----
Från: Don Wilhelm [mailto:[hidden email]]
Skickat: den 11 december 2006 14:34
Till: Samir Popaja; [hidden email]
Ämne: RE: [Elecraft] XV144 state of the art or ... Test of the Large
SignalBehaviour of some 144 MHz Radios?


If I read it correctly, this 'test report' and comments were for the K2
operated without the transverter, but all the data presented was for testing
with a transverter.

I am not certain of this individual's intent, but it would appear to me that
he was determined to present the K2 in a bad light.

For one, I do not understand why he chose only to operate the K2 with the
preamp ON when used with a transverter - the transverter should provide all
the front-end gain needed, and turning the pre-amp on should accomplish
nothing for weak signal detection, but certainly does reduce the IF receiver
dynamic range (and thus effects his 'blocking test').  In addition, he used
2 borrowed K2s, and we have no information about the health of these K2s,
they may not have been operating properly.  Remember that the K2 is not an
'off the shelf' transceiver, and setup and alignment is done by the
individual builder rather than on a factory assembly line.  Many K2s are
operating at top performance, but many are not.  Alignment and calibration
are not difficult, but we have no assurance that it was done correctly for
the K2s used.

All in all, this report does not square with others which do document the
test setup and conditions used along with unbiased results.  I refer you to
the ARRL lab test which do document their entire setup and test methodology.
Since the results in this 'report' are quite different than from other
reports, I believe he either had malfunctioning K2s to work with or intended
to skew the report.

73,
Don W3FPR

> -----Original Message-----
> Hello,
>
> Taken from, the http://www.df9ic.de/tech/trxtest/trxtest.html
>
> "The Elecraft K2 also has a low IF design using conventional VCOs
> which should result in a good LO noise supression but does not.
> You may compare the ARRL test results of the LO noise that
> Elecraft publishes on their own website and which is closely
> within our blocking test result (our measured -95 dB RX blocking
> in 20 kHz offset is equivalent to -129 dBc/Hz LO noise). The high
> level of TX noise shows that there seem to be design flaws
> choosing too low signal levels internally. The AGC threshold is
> ridiculously high (subjective impression). I also do not
> understand why it uses low quality ladder crystal filters instead
> of a filter from monolithic duals like any other radio does.
> Overall it was the worst HF radio in the test (OK, a 144 MHz
> IC910H is still worse...)."
>
> Is the K2 + XV144 really bad combo or the others transverters are
> much better?
>
> 73' SM7VZX
>

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