Eton E1 User Manual
choose between internal and external antennas. The E1 does not have an inboard ferrite antenna,
which has caused outcry among some users. Instead the whip is supposed to be used for MW
reception as well as SW reception. Many have also commented the lack of a carrying handle. No
problem for me, and the rubberised surface it has actually makes it very safe to hold.
which has caused outcry among some users. Instead the whip is supposed to be used for MW
reception as well as SW reception. Many have also commented the lack of a carrying handle. No
problem for me, and the rubberised surface it has actually makes it very safe to hold.
The 77-page manual is for the most part well written. It also contains a quite detailed specification
list, and a block diagram. The appendix has an entry-level introduction to SW listening which could
have been better, and obviously not made with the E1 in mind so maybe they borrowed the text
from somewhere else.
list, and a block diagram. The appendix has an entry-level introduction to SW listening which could
have been better, and obviously not made with the E1 in mind so maybe they borrowed the text
from somewhere else.
Sensitivity
The first thing I usually do when I get a new radio, is to measure its sensitivity. To date I do not
recall having seen sensitivity figures on the E1, except Eton's own specifications (Less than 2.0uV
for the whole tuning range in AM, 1000 Hz, 30% mod but bandwidth not stated. 7 kHz?)
The first thing I usually do when I get a new radio, is to measure its sensitivity. To date I do not
recall having seen sensitivity figures on the E1, except Eton's own specifications (Less than 2.0uV
for the whole tuning range in AM, 1000 Hz, 30% mod but bandwidth not stated. 7 kHz?)
So I pulled out my signal generator and AC voltmeter and started measuring. I was stunned.
From deep in the LW band right through MW the AM sensitivity was -112 to -115dBm, mostly
around -114 so in fact better than 0.5uV!
From deep in the LW band right through MW the AM sensitivity was -112 to -115dBm, mostly
around -114 so in fact better than 0.5uV!
Could the signal generator results be duplicated in real life? Well almost. I tested the E1 and a
746Pro on the Australian 4KZ-1620 which was a threshold levels at the time. Audio recovery in the
0.6uV 746Pro was marginally better than the E1. But the margin was very narrow indeed.
746Pro on the Australian 4KZ-1620 which was a threshold levels at the time. Audio recovery in the
0.6uV 746Pro was marginally better than the E1. But the margin was very narrow indeed.
Modes, AM Synchronous Detection
In addition to the usual modes AM and SSB (which can be used for ECSS), the E1 is equipped with
a selectable-sideband AM synchronous detector (AMSD). The ECSS technique is supposedly well-
known among DX-ers so I will not go into that subject here except note that the E1's ECSS
reception is very good, once the frequency alignment has been done.
In addition to the usual modes AM and SSB (which can be used for ECSS), the E1 is equipped with
a selectable-sideband AM synchronous detector (AMSD). The ECSS technique is supposedly well-
known among DX-ers so I will not go into that subject here except note that the E1's ECSS
reception is very good, once the frequency alignment has been done.
So what does AMSD do? Some say that AMSD is the life and soul of a receiver - hinting perhaps
that a non-AMSD receiver is no good. Baloney. For further enlightenment on the possible virtues of
AMSD, please read Dallas Lankford's
that a non-AMSD receiver is no good. Baloney. For further enlightenment on the possible virtues of
AMSD, please read Dallas Lankford's
on the subject.
AMSD is often associated with reducing distortion caused by selective fading. This is true, but you
don't really need an AMSD for that; you can use an Elliptic Low Pass Audio Filter (
don't really need an AMSD for that; you can use an Elliptic Low Pass Audio Filter (
instead. Selectable-sideband AMSD can also be used for reducing interference from one side much
the same way as with ECSS.
the same way as with ECSS.
In general, AMSD has one downside compared to ordinary AM: It is usually non-transparent; it
needs to lock onto a signal. This takes time, and is often accompanied with growling when the radio
tries to center on the passband. Some AMSDs loose lock fast, some stay put.
needs to lock onto a signal. This takes time, and is often accompanied with growling when the radio
tries to center on the passband. Some AMSDs loose lock fast, some stay put.
The E1's AMSD has three positions; USB, LSB and DSB (double sideband). I tested its distortion-
reducing capabilities on some fading SW frequencies. Reducing distortion will normally be best
when using the sidebands, but I found that the AMSD was very effective even in DSB. On MW
there wasn't much difference on the signals I tested, but if I had tested with groundwave/skywave
blends I believe I might have had the same results as on SW. Comparisons were made with the AM
Slow AGC setting. The conclusion is that if I want to listen to a SW broadcast I will probably use
AMSD.
reducing capabilities on some fading SW frequencies. Reducing distortion will normally be best
when using the sidebands, but I found that the AMSD was very effective even in DSB. On MW
there wasn't much difference on the signals I tested, but if I had tested with groundwave/skywave
blends I believe I might have had the same results as on SW. Comparisons were made with the AM
Slow AGC setting. The conclusion is that if I want to listen to a SW broadcast I will probably use
AMSD.
And locking to a signal is rather straightforward. It does so within half a second, without muting the
receiver's audio, and without growling. Or mostly without growling. If the carrier is far away from
receiver's audio, and without growling. Or mostly without growling. If the carrier is far away from