In article
,
wrote:

On Mar 3, 4:35*am, Telamon
wrote:
In article
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wrote:
dxAce raised the point that he would prefer to upgrade to a 1000 foot
antenna rather than upgrade to a better radio. This is a bit like
which came first? the chicken or the egg? I have had extensive
experience of using 1000ft longwires or beverage antenna's on my
DXpeditions over the years and indeed they do pull in the signals
something awesome. But they also pull in more interfering stations
that want to blot out your faint DX target, and also whatever QRM/RFI
noise is floating around, they pull more of that in too.

So at the end of the day it still means it is better to DX with a top
end radio that suppresses and minimises the offending signals and QRM
that are interfering with your faint DX target.

Over the years I gradually upgraded my radio's to what I thought was
the ultimate, a Drake R8B. I was quite satisfied with that until I
was loaned a Rohde & Schwarz. Although the R & S did not have any
more bells and whistles than my Drake, it was so clearly superior to
my R8B that from then on I hankered after a better radio. The R&S
just pulled in faint stations that did not even register on the R8B
and then was also better able to resolve to audibility stations that
were interfered with much better than the R8B.

So I watched developments and then my good friend Guy pointed me
towards the Icom IC-756PROIII, which I later acquired. This radio was
indeed better than my R8B, see:
http://www.dxing.info/equipment/icom_ic756_plimmer.dxSo the 756Pro3
has really proved itself in the field, culminating in the catch of a
lifetime: 1410 Khz, CFUN, Vancouver BC, Canada, some 14,000 miles
away from the Seefontein DX site. Whether or not I would have got
this catch on my old R8B is a moot point - I don't think so as it was
extremely faint and on the border of audibility, and my DX mates
didn't get it either. So I am happy that the 756Pro3 paid for itself
and that is why I am now upgrading to the new Icom IC-7700 which
should be here in April. If I get only one more rare catch I will be
satisfied that the 7700 has been a worthwhile investment.

But to keep things in perspective, I think the things that are
important to good DX reception are, in order of importance: 1st.] A
decent antenna, the best you can afford or rig up. 2nd.] Location.
Most of us live in the city or suburbs and are either in condo's or
on limited size plots, so our options are limited. That is why
serious DXer's go to a lot of trouble and expense to find the "ideal"
DX location. When you find a decent place, the results are VERY
rewarding. 3rd.] The radio. again, get the best you can afford. The
results just get better and better.

I would liken our hobby to any sport. If you take golf and Tiger
Woods for example. He has only the latest and most expensive cutting
edge equipment. If he gets the latest $3000 putter and it allows him
that extra inch nearer the hole, he is satisfied. So it is with radio
gear and antenna's.

Have fun and good DX

You bring up a good argument but tangled in it are a number of factors
that all affect reception.

The chicken and egg question is easy. The antenna is the egg and it
comes first. All antennas are not created equal and are designed to
achieve certian objectives in reception just like radios. In the extreme
the antenna can be highly directional where the desired signal can be
specifically enlarged relative to other signals and noise. In the radio
it is mainly blocking and bandpass filtering. Both antenna
directionality and gain or radio gain, blocking, and selectivity can get
you where you want to go to get that DX.

I'm familiar with Rohde & Schwarz signal generators but not their
receivers. You don't mention the model number of the receiver but I can
speculate on a few things. One would be cost. Chances are the R&S
receiver costs 10 to 30 times the Drake. Two would be that the R&S would
not have such niceties as sync detection or tone controls.

I don't think going to ham transceivers is the way to go unless you are
a ham or are working toward being one. I'm not interested in being a ham
and I don't want to buy a transceiver.

DSP can be a good thing but it depends on how it is engineered. I have
both kinds of radios and the DSP type appears to have no advantage in AM
mode. The DSP radio does appear to work better for SSB. I would expect
that for digital modes the DSP would clearly be superior. Here the
crucial parameter at play I believe is bandwidth. Designed properly DSP
IF and AF filtering is generally much better than analog and so in
application where this is more important the DSP radios can perform
better. Anyone who has operated a radio with several filters has most
likely noticed that as you decrease the bandwidth the receiver noise
floor drops improving signal to noise. Since DSP filters can have very
steep walls and depth over analog filtering you would expect improved
signal to noise and better reception where narrow bandwidths are in play.

There are always performance tradeoffs and you only address what a DX'er
might want and certainly not what I would want in a receiver. What I
want is good performance and good sound. Many DSP implementations have
lousy sound quality with a lot of distortion. Here I noticed that with
DSP you can have a signal in the clear without the pops and hiss and yet
not be able to understand what is being said. I have listened to tapes
of DSP radio reception and noticed that besides not being able to
understand many of the words in speech that it was very difficult to
listen to the recordings after a while. Even when I had a transcript of
what was said and replayed the DSP recordings over again I still could
not make out some of the words. I also found it very tiring to listen to
DSP sound. I'll take the pops, whistles, and hiss over the DSP
distortion anytime.

Here is an observation I have made on DSP sound. Have you ever listed to
a coast to coast show with one of those reverse speech guys on? I don't
know about other people but sometimes listening to DSP SW recordings was
not unlike listening to those reverse speech recordings.



Telemon, I didn't deal in detail about the 1000 ft beverage antenna,
because the subject of antenna's is vast and the number of huge
technical tomes written on the subject will keep you going for the
rest of your life.

I see you have a poor opinion of DSP receivers, so I can only presume
you experienced the faults of the early models that only had 16 bit
engines. My 756Pro3 has a 24 bit engine with 32 bit processor and I
assure you suffers from none of the problems you mention that applied
to the earlier offerings like the JRC NRD545D.
I wrote a detailed description of my experiences of the 756Pro3's
audio and filter at:
http://www.dxing.info/community/view...607b7f67e8ff1a
ab600e79c4f
I assure you the audio on the 756Pro3 is top notch, only thing it
lacks is a synch detector.

Rohde & Schwarz did indeed make receivers for HF, the last of them
being the EK895, which unfortunately was so expensive that it could
only be affordable to professional and government operations. They
don't make stand alone receivers anymore, only modular HF units that
fit into a more comprehensive monitoring PC run station. The R&S EK
receiver I had use of for several months was the analogue model just
before the EK895 - it's performance was just awesome. It's outstanding
performance was not due to any fancy pre-amps, but rather superb
circuitry, high quality components and build, and top notch filters.
In performance the only hobby radio that ever came near it in
performance was my pals Drake R7A. Both these receivers could resolve
DX signals that my R8B couldn't.

Of course it's different tricks for different dicks. What I am looking
for in a top end receiver is a complete overkill for the fella that
just want's to potter around and get good sound out of AM HF
broadcasts.

OHIM (Oh hell it's Monday) enjoy your radio and good listening


Yeah, this should be an exciting week.

I didn't mean to convey the impression that DSP receivers are just no
good. My RX340 sounds just fine but I prefer the sound of the R8B for AM
signals. The RX340 works really well on SSB but this is different
program material than what is on AM mode the broadcasters use.

No question that DSP is the way to go on digital signals as the software
filters are much faster, sharper, and deeper than the analog and so you
can get much better error rate ratio.

I think DSP is clearly better for SSB voice also but when it comes to
listening to AM mode broadcast that's where it has some drawbacks and
these can be minimized but they are not going to be biased that way in a
ham transceiver where the emphasis is on SSB.

I think that a really good sounding DSP receiver for AM broadcast can be
made if it is designed with that mode in mind.

--
Telamon
Ventura, California