[Fwd: LF: Rcvr Sensitivy tests]

[Andre' Kesteloot]

vernall wrote:

> Peter Dodd wrote:
> >
> >  Andre' Kesteloot said
> >
> > > Rycom 3121 (transistorized)  -106
> > > Icom IC-735    -116
> > > Rycom 2174A (tube type)     -116
> > > Icom IC-720    -126
> > > Cubic (US Navy rcvr)    > -127
> > > NRD 525    > -127 dbm
> > > Icom R-71 A    >-127
> >
> > As you will have read in the Low Frequency Receiver chapter of the LF
> > Source Book, we have found that receiver sensitivity is often not the
> > limiting factor. John, G4GVC, found that the Kenwood TS-850S, with CW
> > filters on both IFs, was the best receiver for LF. After hearing of
> > John's receiver experimental work I bought a second hand '850 and it
> > is the best receiver I have ever used.
> > Andre', you appear to have a wide range of receiver equipment so we
> > would be interested to see how the TS-850 compares.
>
> > Regards, Peter, G3LDO
>
> Yes, adding to the table with the TS-850 as well as other "general
> coverage" amateur receivers or transceivers is of interest.  The
> equipment I use most often on the 165-190 kHz LF band in New Zealand is
> an Icom IC-735, which shows as one of the poorer sensitivity receivers
> in the tests by Andre.  I knew that sensitivity rolled off below about 1
> MHz, and is well down at the 100 kHz lower tuning limit.  Accordingly, I
> use an external pre-amplifier with about 20 dB gain, and with good low
> pass filtering to prevent MF AM broadcast signals from overloading
> either the pre-amplifier or the following receiver (broadband RF
> response on the lowest frequency range).  So while it is handy to have a
> receiver that does have good sensitivity on the LF band of interest, it
> is also possible to build a suitable external pre-amp to compensate.
> The ability to be able to detect QRN as the major component of noise is
> a practical way of verifying that a receiver has adequate sensitivity.
>
> Bob ZL2CA