I have had mine for a few years I just started doing the mods to it. But how do
I tell which version I have.

That is why I posted the results.   VLF and LF tend to be better in the
winter months (early sunset reduces D layer aborption), and for some reason
the past two nights have been the best I have ever heard.  I am getting
2,000 km DX from NDBs, all using a simple long wire.  My description of the
antenna was to encourage others to build this relatively cheap and simple
method of getting the most out of their RX.  It is really good on the ham
bands as well.

Good hunting and 73.


Ian

-----Original Message-----
From: RADIOSHACKDX394@yahoogroups.com
[mailto:RADIOSHACKDX394@yahoogroups.com] On Behalf Of Norman Davies
Sent: Friday, December 11, 2009 1:47 PM
To: RADIOSHACKDX394@yahoogroups.com
Subject: Re: [RADIOSHACKDX394] DX-394 on Long Wave

2009/12/11 Ian Baines <baines@...>

>
>
> Iceland (189 KHz), Morocco
> (171), Germany (183).
>
> Thanks for the ideas. I've not tried LW for a good while.

norman.

2009/12/11 Ian Baines <baines@...>

>
>
> Iceland (189 KHz), Morocco
> (171), Germany (183).
>
> Thanks for the ideas. I've not tried LW for a good while.

norman.

>
>


[Non-text portions of this message have been removed]

I use my DX-394s for listening to NDBs (beacons) on 150 - 500 KHz.   Don't
ask me why, but this band fascinates me - with its roots in early radio
history and ongoing albeit archaic use for beacons and European
broadcasting.



My shack is very sophisticated (not) with a 250' coax feed to a 75' end fed
long wire antenna.  I am listening in a suburban neighbourhood with 12 kV
power lines within 30 m of the antenna, so one would think that this band
would be full of noise and QRM.   In order to stop the BC interference which
overloads the front end, I have installed a 60 dB BCB filter in the feed
line, which makes the set very sensitive on the other bands.  And is it
important to use a UNUN (a coax balun) at the antenna feed point, as well as
grounding the coax braid at the feed point.   Surprisingly, a long wire
located at least 15 m from all other power lines is quite quiet on the low
bands.



The last two nights have brought a bonanza of European broadcasting on long
wave, with solid signals for long periods from Iceland (189 KHz), Morocco
(171), Germany (183).   Not bad for a simple DX-394 which can be red hot on
the low frequencies if given the chance.



I confirm the stations by simply using the internet to listen to the
broadcast directly.  The signal from my rx is the same, albeit often ahead
of the internet version.



I have learned that a long wire and a long coax feed line, with BCB filter
and UNUN really makes the DX-394 sing.   It is even hotter on the low bands
from my island location with a 250' coax feed and a 200 m long wire.



Ian

VE3DJI





[Non-text portions of this message have been removed]

Thinning the herd...  so I am selling my
Realistic DX-394 Receiver,  as modified and tuned by
the Famous Lowbander - has  KIWA filter installed,
with switch on the back to work it.   As far as I know,
everything  works as it is supposed to work.  Case is
immaculate with very few surface blemishes (it has
a rubberized surface so it has some signs of wear, but
minimal at best.)    I do have the whip antenna for it -
and it is straight as new.

Photos here:

http://www.flickr.com/photos/minirichards/sets/72157622841069433/

$200 Plus $10 shipping - PayPal or cash.
(I will eat additional cost to ship if any.)

Offering it to the collectors here, before I try eBay.
Sold As Is as it is vintage electronics but I have had
no problems with it.   I bought it for a nightstand rig,
and hardly ever used it.   I have Kenwood and TenTec
gear in the ham shack, so I never use it.  I think it
should find a nice home and get played a lot.  No
reason to have it just sitting on my nightstand doing
nothing.

Also, check out the three GE Super Radios I have pictured
in my Flickr.com photostream... those go next.

Please email me privately if questions or interested in buying.

k8jhr  at  arrl  dot net

===========  Richards - K8JHR  ==============

Hi Tom thanks for the reply I have done a comparison with the AOR 3000 on not
only 5.680 but 11.176 and most of the oceanic stations and volmets in the uk and
the states
and they all tune in ok with in a few Hertz of each other .I think the DX394 is
closer than the AOR so perhaps I may have got away with it .The tweak I gave VR2
was very slight.
The tests that have been done have covered most of the  DX394 spectrum .So could
I have been lucky with the sight correction with VR2.

  Dave.

Dave,

Chances are high that this one adjustment has corrected an error at this one
frequency in the mode chosen but may have created errors at other frequencies
and modes. But you might have been lucky! VR2, in conjunction with L6 affect the
nominal frequency and the width and linearity of the range of frequencies over
which the 2nd Local Oscillator is tuned by a digital-to-analog voltage
converter. That range is supposed to be 5 kHz wide centred on 44.545 MHz and
tuned in nominally 50 Hz steps. Dx-394 alignment is pretty complex and overall
error is made up of errors in the 1st LO, the 2nd LO, and, for SSB/CW modes,
also the BFO. If all you listen to is AM mode and broadcasters on a 5kHz spacing
band plan, you might find your adjustment to be quite satisfactory, but only if
the 1st LO is correctly aligned. For modes requiring the BFO, and ability to
tune within 50Hz of any carrier frequency, I would bet your radio is out of
whack.

Tom VE3MEO

Hi I wonder if anyone can please give me a little advice I have a DX 394 some
time ago I noticed  when tuned to say 5.680 it would not tune in it would be
lower 5.677 so to get over this I gave VR2 a slight tweak and this has now
solved the problem it now tunes in a spot on for clear listening at 5.683 VR 2
was the only adjustment I made .The question is
Have I made a detrimental adjustment as every thing seems ok and no loss of
sensitivity.

Dave E

Shortwave listener for 25 years
Other sets AOR 3000 AKD Uniden 3500xtl Uniden 758xtl Plus transceivers

--- On Tue, 11/24/09, Tom H <holden_family@...> wrote:

Chris, yes C170 is part of the RC damping feeding the A/D converter for the
S-meter. It's only 1u.
Reply: Yes, I am aware of that. I replaced it with a new 1µF electrolytic.

I don't quite get the picture regarding S7 and weak signals - are you saying the
meter will not drop below S7? If so, is it your sense that you are still getting
good AGC action?
Reply: Yes, that is correct. The meter will NOT drop below S7. And I'm sure
that the AGC action is fine, esp. based on the fact that the meter never moved
when I tried that 47µF cap.
 
Have a look at TP2, the RF/IF gain control voltage. Make sure the RF Gain
control is turned to max. If the AGC is not swinging enough, then the problem
could be that Q9 is blown or there's a different leaky cap, e.g., C69, C161.
Reply: Been busy lately and haven't had a chance to do any further testing or
look at schematic (I will take a look at Q9, C69, C161 etc shortly), but ...
see reply to question on mods following.
 
Have you been modifying?
Reply: Just purchased the receiver at a the Markham hamfest in October. I have
not done any mods to it ... yet. I am just trying to fix the S meter problem
first.
Further, I just noticed that the filter CF2 has been removed and also a SMT
resistor close to it . I found the resistor tacked on to a screw that holds
the PC board to the chassis. It is  2.2KΩ and with the receiver bottom up and
the front facing you, it is just to the right of and perpendicular to D20
stamped on the board.
 
Which version?
Reply: I believe it is the original version. Serial no. is 002417 (made for USA
market). The PC board is stamped with the following: AG8894V-O and GE-94B-1327
 
Chris
VE3MCX




       __________________________________________________________________
Be smarter than spam. See how smart SpamGuard is at giving junk email the boot
with the All-new Yahoo! Mail.  Click on Options in Mail and switch to New Mail
today or register for free at http://mail.yahoo.ca

[Non-text portions of this message have been removed]

N4GUD de N8CT

If you are interested in a DX-394b with a few of the mods already done, email me
at n8ct@... and we'll discuss it further.
Thanks,
73 de Tom N8CT

--- In RADIOSHACKDX394@yahoogroups.com, "N4GUD" <N4GUD@...> wrote:
>
> Hello,
> I am a "newbie" to the 394 site.  I joined because I would like to obtain a
nice 394b, maybe with mods already performed.  I am a very active Amatuer Radio
operator, and would like a 394b to install down stairs so that I could listen
there vs. having to come upstairs everytime I want to sit a listen.  I have a 
MINT condition AOR AR-8200MKII that I'd like to trade for the 394b, so if any of
you guys are interested, let me know.  I know the 8200MKII is worth more, but
the 394b would suit my needs better as a table top reciever.
>
> 73 John/N4GUD
>
> [Non-text portions of this message have been removed]
>

Hi guys,

I have not found the 3V VL2020/1HF lithium battery on the local shopps here in
Bolivia.

Could I sustitute it by other?

--- On Tue, 11/24/09, Tom H <holden_family@...> wrote:


From: Tom H <holden_family@...>
Subject: [RADIOSHACKDX394] Re: DX-394 S meter
To: RADIOSHACKDX394@yahoogroups.com
Received: Tuesday, November 24, 2009, 11:50 AM


 



Chris, yes C170 is part of the RC damping feeding the A/D converter for the
S-meter. It's only 1u.

I don't quite get the picture regarding S7 and weak signals - are you saying the
meter will not drop below S7? If so, is it your sense that you are still getting
good AGC action? Have a look at TP2, the RF/IF gain control voltage. Make sure
the RF Gain control is turned to max. If the AGC is not swinging enough, then
the problem could be that Q9 is blown or there's a different leaky cap, e.g.,
C69, C161. Have you been modifying? Which version?

Tom VE3MEO

--- In RADIOSHACKDX394@ yahoogroups. com, "Christopher S." <rickersred1@ ...>
wrote:
> after observing the S meter for over an hour yesterday, I can now see that it
will not register any signal below an S7.
>  
> It recieves well on the 30' wire I have strung out in my basement workshop,
but will not register weak signals on the S meter.









       __________________________________________________________________
Ask a question on any topic and get answers from real people. Go to Yahoo!
Answers and share what you know at http://ca.answers.yahoo.com

[Non-text portions of this message have been removed]

Chris, yes C170 is part of the RC damping feeding the A/D converter for the
S-meter. It's only 1u.

I don't quite get the picture regarding S7 and weak signals - are you saying the
meter will not drop below S7? If so, is it your sense that you are still getting
good AGC action? Have a look at TP2, the RF/IF gain control voltage. Make sure
the RF Gain control is turned to max. If the AGC is not swinging enough, then
the problem could be that Q9 is blown or there's a different leaky cap, e.g.,
C69, C161. Have you been modifying? Which version?

Tom VE3MEO

--- In RADIOSHACKDX394@yahoogroups.com, "Christopher S." <rickersred1@...>
wrote:
> after observing the S meter for over an hour yesterday, I can now see that it
will not register any signal below an S7.
>  
> It recieves well on the 30' wire I have strung out in my basement workshop,
but will not register weak signals on the S meter.

Or it might be neither A nor B. Please read the FAQ.

73 de Tom VE3MEO

I have 2 394s How can i tell what thay are-A or Bs ? Thanks 73 Dan-KC9IGD




[Non-text portions of this message have been removed]

IIRC, the AGC voltage is sent to the A/D converter for the S-meter via a RC
circuit to dampen the variations. The C is an electrolytic. My bet is that it is
intermittently shorting.

73, Tom VE3MEO

--------
 
Hi Tom,
 
I believe that capacitor you were referring to is C170. I removed it and the
meter swung widly. Quickly tried a 47 microfarad I had and the S meter would
never budge - that's exactly what I expected. Anyway, after observing the S
meter for over an hour yesterday, I can now see that it will not register any
signal below an S7. I am not sure if the S meter is damaged or if there is more
than one input into or out of the A/D converter. Any more ideas on what may
cause this? 
 
It recieves well on the 30' wire I have strung out in my basement workshop, but
will not register weak signals on the S meter. Methinks a first step might be
that I'll have to fire up the Marconi 2018 and do an alignment anyway, then get
vback to the S meter.
 
Thanks
Chris
VE3MCX


       __________________________________________________________________
Ask a question on any topic and get answers from real people. Go to Yahoo!
Answers and share what you know at http://ca.answers.yahoo.com

[Non-text portions of this message have been removed]

"But the design itself is reasonably good for the price point they achieved and
the performance is about as good as you'll find in receivers in the $100 range
(new or used) today."

Hi Jim,

I think that's an unfair assessment.  Anything in that price range is still a
low cost portable capable of catching high powered signals but not to chase down
DX or SSB.  These portables remind me of the entry level table-top sets (i.e, DX
120, etc) most of us started out with.  I also own the DX 440, a highly rated
portable from the early nineties; while it picks up many stations with clarity,
it's difficult to catch afternoon broadcasts from Nigeria, France or India (or
even the BBC, Germany and Poland broadcasting to Europe or Africa) as with the
394 using the same antenna and amplified pre-selector.  Same experience with the
DX 160.

Of course, my 394 esd modified by Lowbander which included adding a selectivity
switch to resolve the problem of adjacent station interference (one of the many
problems inherent with the original design).  I also do not know how, when
modified, it compares to it's closest port-o-top competitor, the used but highly
rated Grundig Satellite 800 or the 750 (a scaled down version of it's
predecessor) which can be purchased new for $300.  Is a modified 394 in the same
league?  is a used Satellite 800 worth the additional investment compared to a
modified 394 selling for about $300 less for those on a limited budget.

As you know, I'm a SWLer from the sixties but with little technical know-how but
again, do think it unfair to compare the 394 to the modern $100 portables.

73s always,
Joe






----------------------------------------
> To: RADIOSHACKDX394@yahoogroups.com
> From: w4jbm@...
> Date: Fri, 20 Nov 2009 06:24:39 -0500
> Subject: [RADIOSHACKDX394] Re: A versus B...how much better IS the B version?
>
> Just a quick observation. Many times when you buy a used radio, there's reason
> it's being sold. And it seems like a fair number of time they can be subtle
> problems that aren't immediate obvious unless you had the radio "before"
> and "after".
>
> About a year ago I bought an original model 394. It was sold to me as "works
> great" by a guy who owns a local radio repair place and has a decent
> reputation. It turned out that it worked great with AM, but was a total dog
> on LSB and USB.
>
> Log story short, I went through it end to end and did a complete alignment.
> Along the way I fixed several subtle issues that it would have been easy to
> miss. I also fixed the SSB reception problem (bad transistor and I had to add
> two trimmers to fine-tune the BFO frequencies).
>
> In the end, the radio works great. It's not going to blow away a thousand
> dollar receiver, but it will definitely hold it's own against most of my
> other radios in a similar class.
>
> If someone picks up a used radio, gives it a try, and says it's worthless,
> that information, for me, is worthless. Look at the original reviews for the
> radio. That tells you how it's suppose to work. Follow the threads posted to
> the group on repairs and you'll get an idea of common issues. If you don't do
> radio repairs, you might be better off buying from someone who does (although
> in my case that didn't work--but once I found the problem the guy did offer
> my money back, I just was stubborn and wanted to fix it). Once you've gone
> through it end to end, verified everything is working like it should, and
> realigned it to "factory specs" (because things are going to age over the
> decades) then I'm interested in your opinion of the radio.
>
> For almost any radio more than a decade old, you can go to the reviews at
> eHam.com and find someone who says that they bought one and they're nothing
> but trash. There are some "trash" 394s floating around, no doubt. But the
> design itself is reasonably good for the price point they achieved and the
> performance is about as good as you'll find in receivers in the $100 range
> (new or used) today.
>
> And I feel like I've earned the right to make that observation after spending
> time "under the hood" and fixing many of the ailments of age that mine had.
>
> BTW, some of my best purchases have come from people who claimed the radio was
> trash. I have an Allied SX-190 that the guy I bought it from had recapped
> three or four times and it hummed. "They are a piece of trash. They all hum."
> Look back at the original reviews--it doesn't say "Great radio except they
> all hum." After an hour or so of poking around it turned out that the voltage
> regulator transistor had failed in a way where the voltages weren't far off,
> but a huge amount of current was being drawn and the filter capacitors just
> couldn't keep up with it. I got the radio for next to nothing because "It's
> trash & they hum." Invested an hour into fixing it and about two hours into
> aligning it--it's one of the best vintage receivers I have and it's been a
> while but I believe I paid $35 or $40 for it.
>
> On the original question, I think even an original 394 (not the A or the B) is
> a decent radio. I do like the fact that trimmers were added to the BFO in the
> later versions (and I had to modify mine to allow individual adjustment). But
> if it's in good shape and working right, I think you're getting a decent deal
> on a respectable performing radio and wouldn't worry too much about holding
> out for a B.
>
> A working A is better than a hosed B. :-)
>
> 73 de
> Jim W4JBM
>
> http://www.hamuniverse.com/w4jbm/
>
> "With a soldering iron in one hand, a schematic in the other, and a puzzled
> look on his face..."
>
>
> ------------------------------------
>
> DO NOT KEEP this message in your reply. QUOTE PARTS ONLY if needed for
clarity. STOP BALLOONING of message size.
> Yahoo! Groups Links
>
>
>

Yes, the only significant electrical difference between the A and B is the
latter has the buffer. There may be other minor changes - nobody has carefully
compared every item on the schematics or on the pcb's and reported them here.
And the physical differences are that the A model used the original main pcb
with kluged on modifications that were then integrated in the B pcb.

There could be greater variation in performance (apart from oscillator jitter)
among different units of the same version than there is between the average
performances of the different versions, even when new. Manufacturing tolerances
and aging (not to mention prior mods and adjustments) all affect performance,
especially sensitivity, accuracy, tuning linearity, hum.

73, Tom VE3MEO

A very interesting and enlightening posting.
My first DX 394 was a dog, even the am was lousy. The second '394 was an
unmodified "B" and using the same antenna outperforms many classier and more
expensive radios; I have not even opened the case.
Thanks for the info

Charlie--- Original Message -----(edited)
   From: Jim
   To: RADIOSHACKDX394@yahoogroups.com
   Sent: Friday, November 20, 2009 6:24 AM
   Subject: [RADIOSHACKDX394] Re: A versus B...how much better IS the B version?



   Just a quick observation. Many times when you buy a used radio, there's reason
   it's being sold. And it seems like a fair number of time they can be subtle
   problems that aren't immediate obvious unless you had the radio "before"
   and "after".

   (posting edited)


[Non-text portions of this message have been removed]

Just a quick observation. Many times when you buy a used radio, there's reason
it's being sold. And it seems like a fair number of time they can be subtle
problems that aren't immediate obvious unless you had the radio "before"
and "after".

About a year ago I bought an original model 394. It was sold to me as "works
great" by a guy who owns a local radio repair place and has a decent
reputation. It turned out that it worked great with AM, but was a total dog
on LSB and USB.

Log story short, I went through it end to end and did a complete alignment.
Along the way I fixed several subtle issues that it would have been easy to
miss. I also fixed the SSB reception problem (bad transistor and I had to add
two trimmers to fine-tune the BFO frequencies).

In the end, the radio works great. It's not going to blow away a thousand
dollar receiver, but it will definitely hold it's own against most of my
other radios in a similar class.

If someone picks up a used radio, gives it a try, and says it's worthless,
that information, for me, is worthless. Look at the original reviews for the
radio. That tells you how it's suppose to work. Follow the threads posted to
the group on repairs and you'll get an idea of common issues. If you don't do
radio repairs, you might be better off buying from someone who does (although
in my case that didn't work--but once I found the problem the guy did offer
my money back, I just was stubborn and wanted to fix it). Once you've gone
through it end to end, verified everything is working like it should, and
realigned it to "factory specs" (because things are going to age over the
decades) then I'm interested in your opinion of the radio.

For almost any radio more than a decade old, you can go to the reviews at
eHam.com and find someone who says that they bought one and they're nothing
but trash. There are some "trash" 394s floating around, no doubt. But the
design itself is reasonably good for the price point they achieved and the
performance is about as good as you'll find in receivers in the $100 range
(new or used) today.

And I feel like I've earned the right to make that observation after spending
time "under the hood" and fixing many of the ailments of age that mine had.

BTW, some of my best purchases have come from people who claimed the radio was
trash. I have an Allied SX-190 that the guy I bought it from had recapped
three or four times and it hummed. "They are a piece of trash. They all hum."
Look back at the original reviews--it doesn't say "Great radio except they
all hum." After an hour or so of poking around it turned out that the voltage
regulator transistor had failed in a way where the voltages weren't far off,
but a huge amount of current was being drawn and the filter capacitors just
couldn't keep up with it. I got the radio for next to nothing because "It's
trash & they hum." Invested an hour into fixing it and about two hours into
aligning it--it's one of the best vintage receivers I have and it's been a
while but I believe I paid $35 or $40 for it.

On the original question, I think even an original 394 (not the A or the B) is
a decent radio. I do like the fact that trimmers were added to the BFO in the
later versions (and I had to modify mine to allow individual adjustment). But
if it's in good shape and working right, I think you're getting a decent deal
on a respectable performing radio and wouldn't worry too much about holding
out for a B.

A working A is better than a hosed B. :-)

73 de
Jim W4JBM

http://www.hamuniverse.com/w4jbm/

"With a soldering iron in one hand, a schematic in the other, and a puzzled
look on his face..."

Thanks Tom!   I especially appreciate the "ac6v" link.

What I most like about SWL is the way I can hear about 'events' I thought I
knew about and yet hear a completely different version of it from a
different set of news script writers in a different location, and of course,
the things I only hear about on SW.

Norman.

2009/11/20 Tom H <holden_family@...>

>
>
For a great collection of links to SWL resources, see
http://ac6v.com/swl1.htm

>
> 73, Tom VE3MEO
>
>
>


[Non-text portions of this message have been removed]

--- In RADIOSHACKDX394@yahoogroups.com, "Tom H" <holden_family@...> wrote:
>
> The FAQ does describe the electrical and physical differences among the three
versions but, yes, you would have to dig deeper to find out what are the
differences in performance. Someone familiar with receiver design could readily
infer what aspects of performance would be affected.
>
> Synchronous AM demodulation, when well executed, can offer some advantages
over envelope detection. It is, essentially, the same type of demodulator as
used for SSB, i.e., a product detector with a beat frequency oscillator
injecting a substitute carrier. In fact, one can manually tune AM signals for
zero beat with a SSB demodulator and derive much the same benefit as Synch AM -
this method of tuning is called ECSS (Exalted Carrier Single Sideband). What is
added in Synch AM is circuitry that detects the difference between the AM
signal's carrier and the bfo and pulls the tuning automatically to zero beat.
The benefit of Synch-AM and ECSS is primarily reduced distortion from selective
fading, because the substitute carrier is always strong. One may also suppress
interference by selecting one sideband, although with a sufficiently sharp
filter, that can be done with a conventional AM detector.
>
> DRM is a digital transmission mode being used (experimentally) for SW, MW and
LW broadcasting, primarily in Europe but also from Sackville, Canada. It offers
the benefits of digital quality (all or nothing, no audible interference),
multiplexing of text and image (program-associated and not).
>
> Both Synch-AM and DRM can be implemented with the DX-394 by adding a
455kHz-to-~12kHz converter to the second IF and feeding this 3rd IF  output to a
computer soundcard. The computer runs audio DSP software to carry out the
filtering and demodulation/decoding for the different modes.
>
> The "B" model or the addition of the buffer amp between the 2nd local
oscillator and 2nd mixer of the original and A models is required for adequate
stability.
>
> All of these are described in the Files area here and there is a related group
specialising in Synch-AM.
>
> 73, Tom VE3MEO
>

Thanks for the great discussion Tom.

So the ONLY difference between the "A" and "B" is the addition of the buffer amp
for additional stability?

And again...the ONLY difference between the "A" and the "B"?

I ask because I continue to see confusing discussions about the differences.

Thanks

TMT

Well, Norman, methinks you are an anoraknophobe. My wife and I still have orange
anoraks that we bought at Blacks in London in 1973 and wore around the world. I
think I may still be able to fit into it - it was a somewhat spacious tent in
its day - but have kept it for sentimental reasons, not having worn it for
decades. Over a wool sweater, it provided welcome shelter under a million stars
over a desert in Afghanistan as I tuned my Russian-made Vega portable radio (I
still have it, too) to and between the big guns on SW, trying to ferret out a
newscast from my homeland on Radio Canada International.

This group has never had much discussion about what stations people are catching
or what content they have heard. Its aim, after all, is to assist members in
their understanding of how the DX-394 radio works, how to use it, how to improve
it. There are other forums for reporting/discussing topics that are not so
unique, such as antennas, propagation, unusual modes of modulation, pirates,
broadcasters, utilities, hams, numbers, DXing, program content, politics,
science, philosophy, religion, etc. A sister group was spun off some years ago
with the idea of promoting such discussion among DX-394 users but it died on the
vine.

If you are seeking such discussions and reporting not specific to the DX-394,
have a look at the Yahoo group "shortwaves". For a great collection of links to
SWL resources, see http://ac6v.com/swl1.htm

73, Tom VE3MEO

You seem to disparage the DX-394. Why are you in this group? I love my unit. It
has given me many, many hours of pleasure and has never failed in the twelve
years plus I've owned it!

[Moderator deletion]

--- In RADIOSHACKDX394@yahoogroups.com, WILLIAM MILLAR <wmillar3@...> wrote:
>
> keep the aor  sell the realistic ,cos i got one and there crap,,get your self
an eton 3g

This IS a DX-394 specific group not a forum for wanna-be CIA agents....




--- In RADIOSHACKDX394@yahoogroups.com, Norman Davies <nrdavies.jim@...> wrote:
>
> Hi folks,
>
> I've been cocking an eye or two at these anorackish emails about this DX394
> and that DX394 and the occasional dissmisal of any intelligent talk at all
> on this channel and I've really only got one thing I feel I can safely say
> to you all. It is this:
>
>
> I really don't much care what the the tool is in comparison with another. I
> just care about what it can DO!
>
> I listen to the airwaves and I do it because I'm interested in the
> intelligence I get from it. I'd like a group of listeners like yourselves to
> be interested in some kind of debate about the intelligence we get from
> using this tool. It seems that such a concept is illegal in this group. I'm
> dismayed by that apparency.
>
> PLEASE! PLEASE! stop being such jerks and get on the case. That's why you
> are listeners!
>
> All the very best,
>
> Noeman Davies.
>
>
> [Non-text portions of this message have been removed]
>

ok, sorry about the Jerk bit. But do any of you get the rest of it?

Norman.

2009/11/19 Joseph and Mary Dubin <mjgardenia@...>

>
>
> Norman,
>
> I don't think any of us appreciates being called a jerk.
>
>
>


[Non-text portions of this message have been removed]

Norman,

I don't think any of us appreciates being called a jerk.

Hi folks,

I've been cocking an eye or two at these anorackish emails about this DX394
and that DX394 and the occasional dissmisal of any intelligent talk at all
on this channel and I've really only got one thing I feel I can safely say
to you all. It is this:


I really don't much care what the the tool is in comparison with another. I
just care about what it can DO!

I listen to the airwaves and I do it because I'm interested in the
intelligence I get from it. I'd like a group of listeners like yourselves to
be interested in some kind of debate about the intelligence we get from
using this tool. It seems that such a concept is illegal in this group. I'm
dismayed by that apparency.

PLEASE! PLEASE! stop being such jerks and get on the case. That's why you
are listeners!

All the very best,

Noeman Davies.


[Non-text portions of this message have been removed]

The FAQ does describe the electrical and physical differences among the three
versions but, yes, you would have to dig deeper to find out what are the
differences in performance. Someone familiar with receiver design could readily
infer what aspects of performance would be affected.

Synchronous AM demodulation, when well executed, can offer some advantages over
envelope detection. It is, essentially, the same type of demodulator as used for
SSB, i.e., a product detector with a beat frequency oscillator injecting a
substitute carrier. In fact, one can manually tune AM signals for zero beat with
a SSB demodulator and derive much the same benefit as Synch AM - this method of
tuning is called ECSS (Exalted Carrier Single Sideband). What is added in Synch
AM is circuitry that detects the difference between the AM signal's carrier and
the bfo and pulls the tuning automatically to zero beat. The benefit of Synch-AM
and ECSS is primarily reduced distortion from selective fading, because the
substitute carrier is always strong. One may also suppress interference by
selecting one sideband, although with a sufficiently sharp filter, that can be
done with a conventional AM detector.

DRM is a digital transmission mode being used (experimentally) for SW, MW and LW
broadcasting, primarily in Europe but also from Sackville, Canada. It offers the
benefits of digital quality (all or nothing, no audible interference),
multiplexing of text and image (program-associated and not).

Both Synch-AM and DRM can be implemented with the DX-394 by adding a
455kHz-to-~12kHz converter to the second IF and feeding this 3rd IF  output to a
computer soundcard. The computer runs audio DSP software to carry out the
filtering and demodulation/decoding for the different modes.

The "B" model or the addition of the buffer amp between the 2nd local oscillator
and 2nd mixer of the original and A models is required for adequate stability.

All of these are described in the Files area here and there is a related group
specialising in Synch-AM.

73, Tom VE3MEO

 
I disagree. I have a DX-394 "A" version and it's a great radio. $80 is a very
good deal if it's in good working condition and good cosmetic condition.

[Non-text portions of this message have been removed]