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Wellbrook ALA1530+ vs ALA330S Recommendation in Western USA

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  • k7na6
    I posted the following in the ALA1530 group but, not receiving any replies, thought I would post on this more active and robust Loop Antennas group. I am new
    Message 1 of 7 , Feb 17, 2008
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      I posted the following in the ALA1530 group but, not receiving any
      replies, thought I would post on this more active and robust Loop
      Antennas group.

      I am new to this group but for some time have been monitoring
      Wellbrook discussions on other groups such as SWL Antenna, ALA1530
      and Eton E1-XM. Recently joining this group, I have read through
      many of the archived postings.

      I live in a rather noisey suburban environment in Southern Calif.
      and am contemplating the purchase of a Wellbrook loop. I've nagged
      Andy Ikin repeatedly for information and he has been gracious and
      veryhelpful.

      Although I had thought my choice would be the newer ALA1530S+,
      Andy cautioned that since I have two MW broadcast stations within
      about 10 miles of my home, the 1530+ (without the 10db amplification)
      might result in less of an intermod problem. I had thought the
      additional 10dB gain would be essential here in the western USA.

      Currently, I am in a quandry whether to buy the 1530+ as Andy
      suggests, or run with the 330S for better SW performance. I enjoy SW
      listening but I also want excellent MW sensitivity as well. I kinda
      want it all.

      I am wondering if there are group members living in the Western
      USA, where SW signal strengths tend to be weaker, who can give me the
      benefit of their experiences and recommendations. Will the 1530+
      perform satisfactorily on SW here in the West or have most of you
      elected to use the 330S?

      Also, I am wondering if the "S" designation on the 330S means that
      the same 10db amp is used in the receiver interface box as in the
      1530S+? If that's the case, evidently Andy has somehow desensitized
      the MW coverage to improve results in strong MW environments, but
      this is not the case with the 1530S+.

      My current receivers are the Eton E1-XM and the sub-receiver of my
      Tentec Orion ham transceiver. I am also thinking about the future
      purchase of a Drake R8B, R8, Palstar R30CC, Icom R75, or other
      suitable receiver for AM and SW DXing.

      Thanks in advance for any constructive inputs. Much appreciated.

      Vince
      Carlsbad, CA
    • Jim
      ... this surprises me as most locations in a city have MW stations within 10 miles. Considering the Wellbrook loops are supposed to deal with this as well as
      Message 2 of 7 , Feb 17, 2008
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        I can't answer the bulk of your questions, but:

        --- In loopantennas@yahoogroups.com, "k7na6" <k7na6@...> wrote:

        > Although I had thought my choice would be the newer ALA1530S+,
        > Andy cautioned that since I have two MW broadcast stations within
        > about 10 miles of my home, the 1530+ (without the 10db amplification)
        > might result in less of an intermod problem. I had thought the
        > additional 10dB gain would be essential here in the western USA.

        this surprises me as most locations in a city have MW stations within
        10 miles. Considering the Wellbrook loops are supposed to deal with
        this as well as other types of interference, Andy's caution seems kind
        of strange. Or perhaps I'm missing something?
      • Paul V Birke PEng
        Or perhaps I m missing something? ************************* likely he just wants to make it better I have cjoy 1460 here in guelph about 1.5 miles from me so
        Message 3 of 7 , Feb 17, 2008
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          Or perhaps I'm missing something?






          *************************

          likely he just wants to make it better

          I have cjoy 1460 here in guelph about 1.5 miles from me so it is a real issue

          I never thought much about this till Dallas Lankford and Chris Trask make this intermodulation performance I would say the domininant design factor whereas most of would have though snr and gain

          but I think now the design objective importance is

          intermodulation performance

          snr

          gain

          cost is whatever is needed to achieve the above within reason

          best
          Paul



          [Non-text portions of this message have been removed]
        • cank13cat
          I m gonna take a wild guess that intermod won t be a problem with the Palstar R30CC. I live in Fort Worth where we have some flamethrower MW broadcasters,
          Message 4 of 7 , Feb 17, 2008
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            I'm gonna take a wild guess that intermod won't be a problem with the
            Palstar R30CC.

            I live in Fort Worth where we have some flamethrower MW broadcasters,
            including WBAP on 820. My interest is mainly SW DXing, not MW.
            Occasionally I'll hear some MW very faintly in the background when my
            portables (Sony ICF-2010, Magnavox D2935) are set to LW or SW, but
            I've never heard anything break through the Palstar R30C. Well, there
            was *one* occasion when I set up a cheap Radio Shack active antenna
            incorrectly (bypassed the shield/outer conductor on the feedline), but
            that was strictly spurious imaging due to the active antenna, not the
            radio. Hooking up the feedline correctly eliminated that problem.

            Personally, if it was in the budget, I'd go for the 1530 and use the
            Palstar's attenuation switch if necessary. I'd rather have too much
            antenna than not enough.

            Also - and you might discuss this with Andy - it's possible to hook up
            an attenuator inline with the feedline. I have an attenuating cable
            that I use in conjunction with my cheapo active antenna to reduce
            problems with spurious signals.

            --- In loopantennas@yahoogroups.com, "k7na6" <k7na6@...> wrote:
            >
            > I live in a rather noisey suburban environment in Southern Calif.
            > and am contemplating the purchase of a Wellbrook loop. I've nagged
            > Andy Ikin repeatedly for information and he has been gracious and
            > veryhelpful.
            >
            > Although I had thought my choice would be the newer ALA1530S+,
            > Andy cautioned that since I have two MW broadcast stations within
            > about 10 miles of my home, the 1530+ (without the 10db amplification)
            > might result in less of an intermod problem. I had thought the
            > additional 10dB gain would be essential here in the western USA.
            >
            > Currently, I am in a quandry whether to buy the 1530+ as Andy
            > suggests, or run with the 330S for better SW performance. I enjoy SW
            > listening but I also want excellent MW sensitivity as well. I kinda
            > want it all.
            >
            > I am wondering if there are group members living in the Western
            > USA, where SW signal strengths tend to be weaker, who can give me the
            > benefit of their experiences and recommendations. Will the 1530+
            > perform satisfactorily on SW here in the West or have most of you
            > elected to use the 330S?
            >
            > My current receivers are the Eton E1-XM and the sub-receiver of my
            > Tentec Orion ham transceiver. I am also thinking about the future
            > purchase of a Drake R8B, R8, Palstar R30CC, Icom R75, or other
            > suitable receiver for AM and SW DXing.
            >
          • jr_dakota
            ... It doesn t help that their speccs don t seem to jive with reality ... For instance the 1530S+ shows a higher IP2 and the same IP3 as the 1530+ which really
            Message 5 of 7 , Feb 17, 2008
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              --- In loopantennas@yahoogroups.com, "k7na6" <k7na6@...> wrote:
              >
              > I posted the following in the ALA1530 group but, not receiving any
              > replies, thought I would post on this more active and robust Loop
              > Antennas group.
              >
              > I am new to this group but for some time have been monitoring
              > Wellbrook discussions on other groups such as SWL Antenna, ALA1530
              > and Eton E1-XM. Recently joining this group, I have read through
              > many of the archived postings.
              >
              > I live in a rather noisey suburban environment in Southern Calif.
              > and am contemplating the purchase of a Wellbrook loop. I've nagged
              > Andy Ikin repeatedly for information and he has been gracious and
              > veryhelpful.
              >
              > Although I had thought my choice would be the newer ALA1530S+,
              > Andy cautioned that since I have two MW broadcast stations within
              > about 10 miles of my home, the 1530+ (without the 10db amplification)
              > might result in less of an intermod problem. I had thought the
              > additional 10dB gain would be essential here in the western USA.
              >
              > Currently, I am in a quandry whether to buy the 1530+ as Andy
              > suggests, or run with the 330S for better SW performance. I enjoy SW
              > listening but I also want excellent MW sensitivity as well. I kinda
              > want it all.
              >
              > I am wondering if there are group members living in the Western
              > USA, where SW signal strengths tend to be weaker, who can give me the
              > benefit of their experiences and recommendations. Will the 1530+
              > perform satisfactorily on SW here in the West or have most of you
              > elected to use the 330S?
              >
              > Also, I am wondering if the "S" designation on the 330S means that
              > the same 10db amp is used in the receiver interface box as in the
              > 1530S+? If that's the case, evidently Andy has somehow desensitized
              > the MW coverage to improve results in strong MW environments, but
              > this is not the case with the 1530S+.
              >
              > My current receivers are the Eton E1-XM and the sub-receiver of my
              > Tentec Orion ham transceiver. I am also thinking about the future
              > purchase of a Drake R8B, R8, Palstar R30CC, Icom R75, or other
              > suitable receiver for AM and SW DXing.
              >
              > Thanks in advance for any constructive inputs. Much appreciated.
              >
              > Vince
              > Carlsbad, CA
              >

              It doesn't help that their speccs don't seem to jive with reality ...

              For instance the 1530S+ shows a higher IP2 and the same IP3 as the
              1530+ which really isn't logical because of the 10db gain and Andy
              admits as much when he suggests the lower gain version ... This is
              what happens when the specmanship game is played and they don't tell
              you what they are really measuring, input IP2 and IP3 or output IP2
              and IP3 ... We have to assume it's output IP2 and that the input IP2
              will be degraded by the 10db gain of the extra amplifier in the 1530S+

              If you think IP2 is going to be a problem because of nearby
              transmitters then the best option would be the 1530+ and if you think
              you'll need more gain you can add a good outboard 10db preamp such as
              the Kiwa Broadband Preamp 2.0 or DX Engineering DXE-RPA-1 (And I bet
              that the added 10db preamp in the Wellbrook is the same basic design
              as these two) ... You may also find that a MW BCB filter to be of use
              for above the MW BCB ... Kiwa makes a good 10db preamp with the MW BCB
              filter built in, so that might be your best option as you won't be
              needing a preamp for the MW BCB, your location will be way too noisy,
              so you can just take out the preamp/filter combination for the MW BCB

              Then you can use the preamp (and BCB filter) and leave it inline and
              when you want to DX the BCB you can take it out ... You may not even
              need a preamp if you have a decent one built into your radio, for
              instance I have an Icom IC-R71a and it has a balanced 10db preamp that
              pretty stout already, not quite as good as the two preamps mentioned
              above (Or my homebrew versions of them) .... on the other hand my Ten
              Tec RX320D has no preamp and without a MW BCB filter (I took the
              internal one that degrades everything below 1800Khz) when I'm SW DXing
              it the front end will crumple from the two nearby AM BCB transmitters,
              not just from IP2 but from Blocking which desensitizes the entire
              front end

              JR
            • k7na6
              ... 1530S+ ... JR: Thanks for the excellent suggestions with regard to use of external amps if needed. It appears that the ALA330S or the ALA1530+ will offer
              Message 6 of 7 , Feb 18, 2008
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                JR wrote:

                > It doesn't help that their speccs don't seem to jive with reality ...
                >
                > For instance the 1530S+ shows a higher IP2 and the same IP3 as the
                > 1530+ which really isn't logical because of the 10db gain and Andy
                > admits as much when he suggests the lower gain version ... This is
                > what happens when the specmanship game is played and they don't tell
                > you what they are really measuring, input IP2 and IP3 or output IP2
                > and IP3 ... We have to assume it's output IP2 and that the input IP2
                > will be degraded by the 10db gain of the extra amplifier in the
                1530S+
                >>
                > JR

                JR:
                Thanks for the excellent suggestions with regard to use of
                external amps if needed. It appears that the ALA330S or the ALA1530+
                will offer the best options for my circumstance. Andy Ikin made these
                recommendations in emails that we have traded back and forth.

                Mr. Ikin also sent some additional information that I would like
                to share with the group to shed some light on the IP2/IP3 and
                amplification issues of the Wellbrook loops:

                "Reference to concerns about intermodulation performance of
                Wellbrook Loops; user feedback over the past 10 years has only
                highlighted a handful of actual problems with the ALA1530 where the
                antennas were deployed within a few miles of multiple 50-200kW BCB
                transmitters. Notwithstanding the above, the ALA1530+ was introduced a
                few years ago to provide much improved MW IOP3. Also in the past 6
                months the new ALA1530 has a much higher MW IOP3 compared to the old
                model.

                "The level Intermodulation experienced when using active
                antennas; loops or Whips is dependant on the incident field strength
                of the most powerful signals, the Antenna Factor and the Receiver
                Intermodulation performance. Where the incident field strength is very
                high the Receivers' IMD performance can be the limiting factor.

                "The measured MW Antenna Factor of the ALA1530+ is approx. 10db
                i.e. the loop output dBuV is 10dB lower than the field strength in
                dBV/m

                "Therefore if the antenna is deployed approx. 15km from 2 x 50kw
                MW transmitters, the incident field strength assuming good ground is
                100dBuV/m. Thus with an antenna Factor of 10db the signal level at the
                output of the antenna is 90dbuV or –17dBm (over S9+50dB). This is the
                same signal level as specified in the ALA1530+ Data Sheet. So the 2nd
                order intermod. is approx. -110dBm and the 3rd order intermod. is –
                131dBm. Most receivers with inputs as high as –17dBm show much higher
                levels of intermod. compared to the active antenna.

                "Increasing the antenna gain by say +10dB using an amplifier
                with similar IOP2/3 as the antenna, we may start to see some
                noticeable 2nd order intermod. providing one is using a receiver with
                much higher IIP2 than the antenna. Most modern receivers just can't
                handle multiple S9+60dB signals.

                "One suggested way to achieve the higher antenna gain at HF
                without overloading the receiver is to fit a MW hi-pass filter between
                the antenna and the 10dB antenna amplifier. There can be problem with
                this method; simple low cost hi-pass filters don't provide the correct
                50 Ohm resistive termination in the MW stop-band. Hence, the antennas'
                MW IOP3 can be reduced because it sees a highly reactive load. Ideally
                the hi-pass filter should have also have a diplexer and a low-pass
                filter so that the stop-band signals drive into a 50 Ohm load.
                However, in some situations just adding a 50-100 Ohm resistor across
                the input of the hi-pass filter, will reduce some of the IOP3
                degradation."

                I hope the above is informative. Thanks again for your
                suggestions. Much appreciated.

                Vince
                Carlsbad, CA
              • Richards
                I cannot see the issue here. I have the ALA-100M medium aperture loop (i.e., you supply your own wire loop about 20 feet on a side...) and I use it daily
                Message 7 of 7 , Feb 18, 2008
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                  I cannot see the issue here. I have the ALA-100M medium aperture
                  loop (i.e., you supply your own wire loop about 20 feet on a side...)
                  and I use it daily with my amateur transceiver. I often transmit on
                  one antenna or another set to frequency, and use the ALA-100M as the
                  receiving antenna.

                  Never had any problems with AM BCB stations and there are plenty
                  withing ten miles of my operating position. I have used that antenna
                  with cheap portables and fancy table tops and what all in between with
                  no AM station bleed in.

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

                  k7na6 wrote:

                  > "Reference to concerns about intermodulation performance of
                  > Wellbrook Loops;

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