Message-ID: <59E51400.60806@posteo.de>
Date: Mon, 16 Oct 2017 22:18:08 +0200
From: DK7FC <selberdenken@posteo.de>
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To: rsgb_lf_group@blacksheep.org
References: <15ec7c794b3-bff-66@webjas-vac136.srv.aolmail.net> <alpine.DEB.2.11.1710022138560.734@mailn.lipkowski.org> <59D2BD65.4080909@posteo.de> <59D4B109.27652.1415B4FA@mike.dennison.ntlworld.com> <7737095b-edc9-8b5f-ebf5-2a6b2884d425@abelian.org> <ffe7e282-b039-8ad6-f1da-400b64131a98@abelian.org> <aac1062e-eadd-c7c8-0ecc-efac0ff94363@abelian.org> <59D7940D.7080102@posteo.de> <f3db3efe-7c22-90f2-d6cf-ad853de9fb48@abelian.org> <59DA4E78.7020804@posteo.de> <25d84b3d-2077-a3dc-426c-3f9b92940205@abelian.org> <59DB730D.4080803@posteo.de> <59DE3B9F.70705@posteo.de> <50b0a7b4-a6e6-398d-ea56-dbe66490d1b8@abelian.org> <59E4A8C0.4020707@posteo.de> <59E4B566.5030006@posteo.de> <bc1dfbad-2ad3-2420-55a4-818647f86e10@abelian.org> <59E508C6.7090808@posteo.de>
In-Reply-To: <59E508C6.7090808@posteo.de>
Subject: Re: VLF: EbNaut on 2 frequencies
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...i stopped the transmission and will restart with *30 seconds symbol 
length at 20:30 UTC*. All other parameters are unchanged.
I can also run plain carriers later, if of interest. But EbNaut messages 
are more interesting i find.

73, Stefan

Am 16.10.2017 21:30, schrieb DK7FC:
> Hello Paul, VLF,
>
> Thanks for the results. The message '73' is correct! Well, i was 
> unable to hold the antenna current constant on both frequencies, see 
> attachment.
> Let's say the average current on 6510 was just 190 mA. Relative to 200 
> mA that's -0.45 dB. But on 6510, the radiation resistance is higher, 
> giving a gain, relative to 6430 Hz of +0.1 dB. All in all that's still 
> quite negiligible.
> But the difference of the Eb/N0 of both transmissions is > 3 dB. Quite 
> a difference. Do you exclude local QRM of the individual frequencies?
> Our distance is 881 km.
> 6510 Hz has a wavelength of 46.08 km, so our distance is at 19.1 lambda.
> 6430 Hz has a wavelength of 46.66 km, so our distance is at 18.9 lambda.
> A difference of lambda/5, quite close to lambda/4...
> This applies at least for the groundwave.
> Does it help us in any way, the result we saw now?
> On 2970 Hz, this could make a much bigger difference but due to the 
> weaker signal, we can't check is quickly in < 3 hours...
>
> Meanwhile the night has started between us.
> I will repeat the same experiment starting 20 UTC.
> Maybe we will get more impressions...
>
> 73, Stefan
>
> Am 16.10.2017 19:05, schrieb Paul Nicholson:
>>
>> Stefan wrote:
>>
>> > f1 = 6430.005000 Hz
>> > f2 = 6510.005000 Hz
>> > Start time: 16.October.2017  13:00:00 UTC
>> > Symbol period: 15 s
>> > Characters: 2
>> > CRC bits: 6
>> > Coding 16K21A
>> > Duration: 2h32min
>>
>> H-field only:
>>
>> 6430.005000 copied '51' at -1.8 dB and 'ZV' at -1.1 dB;
>>
>> 6510.005000 copied '73' at +3.0 dB;
>>
>> -- 
>> Paul Nicholson
>> -- 
>>

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...i stopped the transmission and will restart with <b>30 seconds
symbol length at 20:30 UTC</b>. All other parameters are unchanged.<br>
I can also run plain carriers later, if of interest. But EbNaut
messages are more interesting i find.<br>
<br>
73, Stefan<br>
<br>
Am 16.10.2017 21:30, schrieb DK7FC:
<blockquote cite="mid:59E508C6.7090808@posteo.de" type="cite">Hello
Paul, VLF,
  <br>
  <br>
Thanks for the results. The message '73' is correct! Well, i was unable
to hold the antenna current constant on both frequencies, see
attachment.
  <br>
Let's say the average current on 6510 was just 190 mA. Relative to 200
mA that's -0.45 dB. But on 6510, the radiation resistance is higher,
giving a gain, relative to 6430 Hz of +0.1 dB. All in all that's still
quite negiligible.
  <br>
But the difference of the Eb/N0 of both transmissions is &gt; 3 dB.
Quite a difference. Do you exclude local QRM of the individual
frequencies?
  <br>
Our distance is 881 km.
  <br>
6510 Hz has a wavelength of 46.08 km, so our distance is at 19.1
lambda.
  <br>
6430 Hz has a wavelength of 46.66 km, so our distance is at 18.9
lambda.
  <br>
A difference of lambda/5, quite close to lambda/4...
  <br>
This applies at least for the groundwave.
  <br>
Does it help us in any way, the result we saw now?
  <br>
On 2970 Hz, this could make a much bigger difference but due to the
weaker signal, we can't check is quickly in &lt; 3 hours...
  <br>
  <br>
Meanwhile the night has started between us.
  <br>
I will repeat the same experiment starting 20 UTC.
  <br>
Maybe we will get more impressions...
  <br>
  <br>
73, Stefan
  <br>
  <br>
Am 16.10.2017 19:05, schrieb Paul Nicholson:
  <br>
  <blockquote type="cite"><br>
Stefan wrote:
    <br>
    <br>
&gt; f1 = 6430.005000 Hz
    <br>
&gt; f2 = 6510.005000 Hz
    <br>
&gt; Start time: 16.October.2017  13:00:00 UTC
    <br>
&gt; Symbol period: 15 s
    <br>
&gt; Characters: 2
    <br>
&gt; CRC bits: 6
    <br>
&gt; Coding 16K21A
    <br>
&gt; Duration: 2h32min
    <br>
    <br>
H-field only:
    <br>
    <br>
6430.005000 copied '51' at -1.8 dB and 'ZV' at -1.1 dB;
    <br>
    <br>
6510.005000 copied '73' at +3.0 dB;
    <br>
    <br>
-- <br>
Paul Nicholson
    <br>
-- <br>
    <br>
  </blockquote>
</blockquote>
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