[time-nuts] Some Ham Gear Measurements

John Ackermann N8UR jra at febo.com
Sat Jun 2 12:38:42 EDT 2007

I just finished doing some phase noise (and as a byproduct, frequency
stability) measurements of a few ham radio HF transceivers and thought
you might be interested in the results:

Many of you may not be familiar with the four rigs that I tested, but
they were an interesting mix:

1.  Yaesu FT-817 5 watt portable transceiver; almost current production
(replaced by a slightly enhanced FT-817ND).  It has an optional TCXO for
its frequency reference.

2.  Icom IC746 Pro 100 watt transceiver.  This is a fairly typical
mid-line rig that's in current production.  It uses DSP fairly
significantly but is not a Software Defined Radio.  It also has an
optional TCXO reference.

3.  Flex-Radio SDR-1000 100 watt transceiver.  The SDR-1000 is a true
SDR and uses a PC with sound card as the signal processing engine.  I
tested the SDR-1000 using its standard 200 MHz XO (not TC) as well as
several external reference sources, as there has been some uncertainty
about the effect of multiplying a 10 MHz reference to 200 MHz on phase

4.  Finally, an old Kenwood TS-520S 100 watt rig with tubes in the final
and a VFO (variable frequency oscillator) for you youngsters.  No
synthesizer at all, just a traditional superheterodyne.

Some of the results may surprise you...


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