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Re: Measure effect of Noise Blanker Mod?

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  • bill_beamon
    Tom; Thanks for the feedback. The other mods made such a great improvement in performance and I guess I expected too much from the NB mod. I ll check it with
    Message 1 of 9 , Sep 1, 2003
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      Tom;
      Thanks for the feedback. The other mods made such a great improvement
      in performance and I guess I expected too much from the NB mod. I'll
      check it with the scope (if it still works).
      KD4FNC
      >
      > [snip]
      > > How are you supposed to measure how much good the
      > NB mod to the 394
      > > actually does? I can't tell...
      >
      > Bill, the Service Manual has a procedure for Noise
      > Blanker Alignment - page 15 - but it needs a signal
      > generator, pulse gen and a scope. That's more than
      > most of us can come up with! So the best you can do
      > without it is to have an impulse noise source that
      > you can control and make subjective judgements of the
      > noise blanking before and after the mod. That
      > requires RF and Audio gains set the same way, tuned
      > to the same frequency range with exactly the same
      > receiving conditions.
      >
      > In my case, I recall being disappointed that there
      > was little improvement on AM but was pleased that it
      > was much better on SSB. Any other comments?
      >
      > Make sure the diode connects to Q34, NOT Q32, an
      > error in a re-post at some point and replicated at
      > several sites.
      >
      > 73, Tom VE3MEO
    • Valveman
      I ve had a Realistic Amplified Shortwave antenna for about two years now and never tried it until today. I obtained in a radio deal and frankly didn t think
      Message 2 of 9 , Sep 1, 2003
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        I've had a Realistic Amplified Shortwave antenna for
        about two years now and never tried it until today. I
        obtained in a radio deal and frankly didn't think much
        of it at the time. Well today, I decided to try it
        out and can say this is a fine little item.
        Lots of gain and what makes it so attractive it that
        there is a pseudo peak adjustment that is very
        effective.
        So adjustable RF gain and preselector.
        Works super on my Sony 2010 and notibly excellent on
        the DX-394.

        If I get any overloading, I simply adjust the RF gain
        and preselector peak. Problem solved.

        You gotta get one. I know RS discontinued this item
        but I see several for sale on Expensive Bay.

        A super item for the antenna challenged. You can even
        connect it to your outdoor antenna and adjust the RF
        gain accordingly.

        I think this item was a sleeper and was dismissed by
        many due to the stigma associated with using an
        amplified antenna system. Believe me this one works
        great and for the $10-$30 I've seen them go for, it's
        a real bargain. Most bang for the buck IMHO.

        Any one else have one of these and want to share their
        experience with the rest of the group?


        Robert VE3RPF



        ______________________________________________________________________
        Post your free ad now! http://personals.yahoo.ca
      • Bill
        Thanks for the info! b Valveman wrote: I ve had a Realistic Amplified Shortwave antenna for about two years now and never tried it
        Message 3 of 9 , Sep 1, 2003
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          Thanks for the info!
           
          b

          Valveman <valveman_6146@...> wrote:
          I've had a Realistic Amplified Shortwave antenna for
          about two years now and never tried it until today.  I
          obtained in a radio deal and frankly didn't think much
          of it at the time.  Well today, I decided to try it
          out and can say this is a fine little item.
          Lots of gain and what makes it so attractive it that
          there is a pseudo peak adjustment that is very
          effective....


          see our website www.amateur-repairs.com


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          Yahoo! SiteBuilder - Free, easy-to-use web site design software

        • Anthony F. Smith
          Hello Robert (and everyone else) yes you re quite right about the radio Shack amplified antenna. A few fellow SWLers here in Rockhampton (Oz) bought them when
          Message 4 of 9 , Sep 3, 2003
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            Hello Robert (and everyone else) yes you're quite right about the radio
            Shack amplified antenna. A few fellow SWLers here in Rockhampton (Oz) bought
            them when they went out the door for $19.95Au. With mine I replaced the
            existing antenna with the Radio Shack 6 foot replacement telescopic antenna!
            Boy! will it drag in the signals. Also I used one of the same 6 foot tele
            elements in a PL-259 setup and it simply screws straight on the back of the
            DX-394. Massive difference yet still allows you to cart it from room to room
            (the DX-394 that is!) I even fitted an RCA female socket to one of my
            portable SW receivers, then used a converter plug (readily available from RS
            etc.) to enable me to use this nifty little amplifier with the portable and
            other receivers that also had RCA sockets. If anyone has a circuit diagram
            (with parts ID) on this unit, perhaps you could scan and e-mail to me?
            Product No. for the Amplified Shortwave Antenna is: Cat. No. 20-280 can't
            remember the Cat No. for the tele element but, it is the only one at RS that
            pulls out to 6 foot! Cheers.

            73
            Anthony (Tony) Smith VK4002SWL / 4RK1SWL
            CQSWN - ARDXC - EDXP - WEWN - DX-394 Group - SWARL

            ----- Original Message -----
            From: "Valveman" <valveman_6146@...>
            To: <RADIOSHACKDX394@yahoogroups.com>
            Sent: Tuesday, September 02, 2003 4:44 AM
            Subject: [RADIOSHACKDX394] Amplified Shortwave antenna


            > I've had a Realistic Amplified Shortwave antenna for
            > about two years now and never tried it until today. I
            > obtained in a radio deal and frankly didn't think much
            > of it at the time. Well today, I decided to try it
            > out and can say this is a fine little item.
            > Lots of gain and what makes it so attractive it that
            > there is a pseudo peak adjustment that is very
            > effective.
            > So adjustable RF gain and preselector.
            > Works super on my Sony 2010 and notibly excellent on
            > the DX-394.
            >
            > If I get any overloading, I simply adjust the RF gain
            > and preselector peak. Problem solved.
            >
            > You gotta get one. I know RS discontinued this item
            > but I see several for sale on Expensive Bay.
            >
            > A super item for the antenna challenged. You can even
            > connect it to your outdoor antenna and adjust the RF
            > gain accordingly.
            >
            > I think this item was a sleeper and was dismissed by
            > many due to the stigma associated with using an
            > amplified antenna system. Believe me this one works
            > great and for the $10-$30 I've seen them go for, it's
            > a real bargain. Most bang for the buck IMHO.
            >
            > Any one else have one of these and want to share their
            > experience with the rest of the group?
            >
            >
            > Robert VE3RPF
            >
            >
            >
            > ______________________________________________________________________
            > Post your free ad now! http://personals.yahoo.ca
            >
            >
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            >
          • randpup
            For what it s worth, I just implemented the noise blanker mod on my original DX-394 (not A or B ). I can t tell the difference. However I did use the
            Message 5 of 9 , Sep 10, 2003
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              For what it's worth, I just implemented the noise blanker mod on my original DX-394
              (not "A" or "B"). I can't tell the difference. However I did use the RadioShack 1N4148
              diode mentioned in the mod notes rather than the recommended Schottky diode
              1N5817/ECG - NTE583 which RS doesn't carry. I think I'll make the trip to a well-
              stocked electronics house downtown sometime next week to buy the elusive
              Schottkey real thing. Perhaps that will make the difference (or not).

              Randy
            • Mike Crabtree
              Randy, I had the same experience the first time I tried the Noise Blanker mod. I thought it wasn t worth the trouble. Then I ordered a good quality Schottky
              Message 6 of 9 , Sep 10, 2003
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                Randy,
                   I had the same experience the first time I tried the Noise Blanker mod. I thought it wasn't worth the trouble.   Then I ordered a good quality Schottky   from Mouser Electronics and it made a huge difference. Here's the part # 78-1N914 (Vishay/Telefunken DO-35 100 V 300ma.) It only costs a few cents!
                use this and it will make the mod very worthwhile!
                Mike   AB0X 
                ----- Original Message -----
                From: randpup
                Sent: Wednesday, September 10, 2003 11:42 AM
                Subject: [RADIOSHACKDX394] Re: Measure effect of Noise Blanker Mod?

                For what it's worth, I just implemented the noise blanker mod on my original DX-394
                (not "A" or "B").  I can't tell the difference.  However I did use the RadioShack 1N4148
                diode mentioned in the mod notes rather than the recommended Schottky diode
                1N5817/ECG - NTE583 which RS doesn't carry.  I think I'll make the trip to a well-
                stocked electronics house downtown sometime next week to buy the elusive
                Schottkey real thing.  Perhaps that will make the difference (or not).

                Randy




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              • randpup
                Mike, that is music to my ears. Thank you for the tip, Mike! That is much appreciated, and I m placing my order tomorrow. (Wow, this is a great group.) :-)
                Message 7 of 9 , Sep 10, 2003
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                  Mike, that is music to my ears. Thank you for the tip, Mike!
                  That is much appreciated, and I'm placing my order tomorrow.
                  (Wow, this is a great group.) :-)
                  Randy


                  --- In RADIOSHACKDX394@yahoogroups.com, "Mike Crabtree" <mcrabtree@k...>
                  wrote:
                  > Randy,
                  > I had the same experience the first time I tried the Noise Blanker mod. I thought
                  it wasn't worth the trouble. Then I ordered a good quality Schottky from Mouser
                  Electronics and it made a huge difference. Here's the part # 78-1N914 (Vishay/
                  Telefunken DO-35 100 V 300ma.) It only costs a few cents!
                  > use this and it will make the mod very worthwhile!
                  > Mike AB0X
                  > ----- Original Message -----
                  > From: randpup
                  > To: RADIOSHACKDX394@yahoogroups.com
                  > Sent: Wednesday, September 10, 2003 11:42 AM
                  > Subject: [RADIOSHACKDX394] Re: Measure effect of Noise Blanker Mod?
                  >
                  >
                  > For what it's worth, I just implemented the noise blanker mod on my original DX-
                  394
                  > (not "A" or "B"). I can't tell the difference. However I did use the RadioShack
                  1N4148
                  > diode mentioned in the mod notes rather than the recommended Schottky diode
                  > 1N5817/ECG - NTE583 which RS doesn't carry. I think I'll make the trip to a well-
                  > stocked electronics house downtown sometime next week to buy the elusive
                  > Schottkey real thing. Perhaps that will make the difference (or not).
                  >
                  > Randy
                  >
                  >
                  >
                  > Yahoo! Groups Sponsor
                  >
                  >
                  >
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                  mushrooming in size.
                  > For archives of prior messages, files, links, photos, user survey, members info,
                  etc., visit http://groups.yahoo.com/group/RADIOSHACKDX394/ .
                  >
                  > To unsubscribe from this group, send an email to:
                  > RADIOSHACKDX394-unsubscribe@egroups.com
                  >
                  >
                  >
                  > Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.
                • perw1
                  I have also just made this mod in my second DX394, wich is original model, the other was B model. You can clearly hear the difference when noise blanker is
                  Message 8 of 9 , Nov 6, 2003
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                    I have also just made this mod in my second DX394, wich is original
                    model, the other was B model.

                    You can clearly hear the difference when noise blanker is used now,
                    specially when there is lots of noice and static on the frequency.

                    I used 1N5818 wich was easier to get hold of. On the first radio i
                    also tried 1N4148 but it really doesn't work very well, i am sure you
                    will hear difference when you get the right diode.

                    Best regards


                    --- In RADIOSHACKDX394@yahoogroups.com, "randpup" <padawer@m...>
                    wrote:
                    > For what it's worth, I just implemented the noise blanker mod on my
                    original DX-394
                    > (not "A" or "B"). I can't tell the difference. However I did use
                    the RadioShack 1N4148
                    > diode mentioned in the mod notes rather than the recommended
                    Schottky diode
                    > 1N5817/ECG - NTE583 which RS doesn't carry. I think I'll make the
                    trip to a well-
                    > stocked electronics house downtown sometime next week to buy the
                    elusive
                    > Schottkey real thing. Perhaps that will make the difference (or
                    not).
                    >
                    > Randy
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