From: DK1IS <DK1IS@kabelmail.de>
To: rsgb_lf_group@blacksheep.org, rsgb-lf-group@groups.io
References: <5CADE53C.30201@posteo.de>
 <e0ba3e0c-ea1e-4858-1291-c88dbd0d69f4@aeritel.com>
 <b94b2f43-2d07-1128-3066-3be4c72cbf62@kabelmail.de>
 <CE1767F5CE1B41C48D7BC015B414DB99@Clemens0811>
 <6f73882e-0f5c-64f3-e0a8-28c187dc822d@kabelmail.de>
Message-ID: <98e27c8c-477d-c2da-c827-a9920539af19@kabelmail.de>
Date: Sat, 20 Apr 2019 23:15:45 +0200
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Subject: Re: LF: NEW quarz resonated VLF antenna
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Am 19.04.2019 um 17:28 schrieb Clemens Paul:
>> Do you think it is possible for a more true comparison to compare the=20
>> quartz resonated wire antenna
>> against he same wire resonated conventionally by an inductor=20
>> regarding field strength and 3dB BW?
>>
Hi Clemens and group,

here is the promised extension of my tests, for better comparability=20
merged with the first results (my post on the reflector from 20190418):

Having no VLF quartz yet, I made some preliminary tests with a randomly=20
available HC-6-U quartz, QRG 2434 kHz, wavelength 123 m.

  * TX: Sythesizer Schomandl MG100M, 300 Hz ... 100 MHz, smallest step
    0.1 Hz, Ri =3D 50 Ohms, P =3D 10 dBm, output tied to first leg of
    quartz, alternatively direct to the antenna wire
  * RX: Perseus SDR with an active rod antenna on my garage, fed by a
    solar system, no external wire connections, air-line distance 100 m
    to my shack
  * Antena wire: 2 m or 4 m, laid out in the shack, tied to second leg
    of quartz, alternatively direct to the TX output
  * alternatively antenna wire only resonated by two roller plus one
    fixed inductors in series, fed directly from the TX output

Results with 2 m antenna wire:

  * with quartz resonator: fres =3D 2,433,908.8 Hz, RX level at resonance
    =3D - 63,1 dBm, - 3dB-bandwidth =3D 48.3 Hz resulting in Q =3D 50391
  * without quartz resonator: RX level =3D - 85,4 dBm resulting in a gain
    of 22.3 dB with quartz
  * comparision: my 13 m T-Marconi with top load 4 x 33 m, tuned to 2434
    kHz and fed by the synthesizer with 10 dBm results in a RX level of
    - 32.1 dBm ;-)
  * with inductive tuning at 2,434,000 Hz: RX level =3D - 60.1 dBm
    resulting in a gain of 3dB compared with quartz. -3 dB-bandwidth =3D
    249 kHz resulting in a loaded Q =3D 9.8

Results with 4 m antenna wire:

  * with Quartz resonator: fres =3D 2,433,773.6 Hz, RX level at resonance
    =3D - 59 dBm. - 3 dB-bandwidth =3D 49.4 Hz resulting in Q =3D 49376
  * without quartz resonator: RX level =3D - 75.4 dBm resulting in a gain
    of 16.4 dB with quartz
  * with indctive tuning at 2,234,000 Hz: RX level =3D - 57.3 dBm
    resulting in a gain of 1.7 dB compared with quarz. - 3 dB-Bandwidth
    =3D 390 kHz resulting in a loaded Q =3D 6.2

With all tests there was no additional resistive matching at the TX=20
output. The tests at resonance showed the usual unbalance between lower=20
and upper - 3 dB-points. With L-tuning the upper is further away from=20
the resonance frequency than the lower. With quartz-tuning this effect=20
is contrawise and of course absolutely much lesser accented. At a first=20
glance L-tuning offers advantages due to its comparable huge bandwidth=20
and the higher fieldstength at the RX site but this could shrink if you=20
really go down to VLF frequencies, very short antennas and short=20
distances. According to the author=C2=B4s claims the quarz resonated syst=
em=20
is usable for short range communication only and there the Q of L-tuned=20
antennas will also grow to high values as well as the losses in the=20
tuning circuit.

As soon as my ordered XTALs will arrive I=C2=B4ll make further tests in t=
he 4=20
kHz-range. If the results happen to differ very much from the preceding=20
tests at 2.4 MHz I=C2=B4ll report about it.

73 es Happy Easter,

Tom, DK1IS


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    <div class=3D"moz-cite-prefix">Am 19.04.2019 um 17:28 schrieb Clemens
      Paul:
      <br>
    </div>
    <blockquote type=3D"cite"
      cite=3D"mid:6f73882e-0f5c-64f3-e0a8-28c187dc822d@kabelmail.de">
      <blockquote type=3D"cite">Do you think it is possible for a more
        true comparison to compare the quartz resonated wire antenna
        <br>
        against he same wire resonated conventionally by an inductor
        regarding field strength and 3dB BW?
        <br>
        <br>
      </blockquote>
    </blockquote>
    <p>Hi Clemens and group,</p>
    <p>here is the promised extension of my tests, for better
      comparability merged with the first results (my post on the
      reflector from 20190418):</p>
    <p>Having no VLF quartz yet, I made some preliminary tests with a
      randomly available HC-6-U quartz, QRG 2434 kHz, wavelength 123 m.<b=
r>
    </p>
    <ul>
      <li>TX: Sythesizer Schomandl MG100M, 300 Hz ... 100 MHz, smallest
        step 0.1 Hz, Ri =3D 50 Ohms, P =3D 10 dBm, output tied to first l=
eg
        of quartz, alternatively direct to the antenna wire<br>
      </li>
      <li>RX: Perseus SDR with an active rod antenna on my garage, fed
        by a solar system, no external wire connections, air-line
        distance 100 m to my shack</li>
      <li>Antena wire: 2 m or 4 m, laid out in the shack, tied to second
        leg of quartz, alternatively direct to the TX output</li>
      <li><font color=3D"#ff0000">alternatively antenna wire only
          resonated by two roller plus one fixed inductors in series,
          fed directly from the TX output</font> <br>
      </li>
    </ul>
    <p>Results with 2 m antenna wire:</p>
    <ul>
      <li>with quartz resonator: fres =3D 2,433,908.8 Hz, RX level at
        resonance =3D - 63,1 dBm, - 3dB-bandwidth =3D 48.3 Hz resulting i=
n Q
        =3D 50391</li>
      <li>without quartz resonator: RX level =3D - 85,4 dBm resulting in =
a
        gain of 22.3 dB with quartz</li>
      <li>comparision: my 13 m T-Marconi with top load 4 x 33 m, tuned
        to 2434 kHz and fed by the synthesizer with 10 dBm results in a
        RX level of - 32.1 dBm ;-)</li>
      <li><font color=3D"#ff0000">with inductive tuning at 2,434,000 Hz:
          RX level =3D - 60.1 dBm resulting in a gain of 3dB compared wit=
h
          quartz. -3 dB-bandwidth =3D 249 kHz resulting in a loaded Q =3D
          9.8</font><br>
      </li>
    </ul>
    <p>Results with 4 m antenna wire: <br>
    </p>
    <ul>
      <li>with Quartz resonator: fres =3D 2,433,773.6 Hz, RX level at
        resonance =3D - 59 dBm. - 3 dB-bandwidth =3D 49.4 Hz resulting in=
 Q
        =3D 49376</li>
      <li>without quartz resonator: RX level =3D - 75.4 dBm resulting in =
a
        gain of 16.4 dB with quartz</li>
      <li><font color=3D"#ff0000">with indctive tuning at 2,234,000 Hz: R=
X
          level =3D - 57.3 dBm resulting in a gain of 1.7 dB compared wit=
h
          quarz. - 3 dB-Bandwidth =3D 390 kHz resulting in a loaded Q =3D
          6.2</font></li>
    </ul>
    <p>With all tests there was no additional resistive matching at the
      TX output. The tests at resonance showed the usual unbalance
      between lower and upper - 3 dB-points. With L-tuning the upper is
      further away from the resonance frequency than the lower. With
      quartz-tuning this effect is contrawise and of course absolutely
      much lesser accented. At a first glance L-tuning offers advantages
      due to its comparable huge bandwidth and the higher fieldstength
      at the RX site but this could shrink if you really go down to VLF
      frequencies, very short antennas and short distances. According to
      the author=C2=B4s claims the quarz resonated system is usable for s=
hort
      range communication only and there the Q of L-tuned antennas will
      also grow to high values as well as the losses in the tuning
      circuit.</p>
    <p>As soon as my ordered XTALs will arrive I=C2=B4ll make further tes=
ts
      in the 4 kHz-range. If the results happen to differ very much from
      the preceding tests at 2.4 MHz I=C2=B4ll report about it.</p>
    <p>73 es Happy Easter,</p>
    <p>Tom, DK1IS<br>
    </p>
    <p><br>
    </p>
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