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Темы - rw3adb

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1
ДВ антенны / Антенна Луиса EA5DOM
« : 26 Сентябрь 2019, 23:58:32 »
Луис мне прислал тут письмо с описанием своей антенны.
90м вертикал.
Насколько я понял, конструкция похоже на ту, что испытавл недавно Андрей RN3AGC  - удочка с балкона и два провода параллельно вниз.
Заземление- трубы холодной воды.
Только живет он повыше, потому и эффективность антенны получлсь в разы повеселее.
Пишет, что усилитель перенес  на терасску крышы, я так понимаю чтобыне шумел вентиляторами и не мешал домашним спать и готов вещать чуть не круглосуточно. -)

Оригинал ео письма:

Привет Роман !

I have answered in the Russian group. Hope Google translator is not extremely bad on Russian
I'm using English->Russian translation, which should work better than Spanish->Russian

Hope to get the PA working in the top terrace soon. So I will be able to keep it running all night long
without fan noise at home. And then we will be able to get the good openings at sunrise in your QTH

I read that you don't understand how my antenna work. May be I can explain you, so you can translate

I live in a 26 floor building tower. The top terrace is flat (no roof with tiles) and about 80m to the ground
Then I have a 10m fiberglass pole. The pole supports a vertical wire and two sloppers to provide some capacity
about 150pF. The coils to resonate the antenna are also in the top terraza and the PA should be there. Actually
is feeded by a coax from QTH in the 16 floor

So fa so good. But the ground of the coax or PA is connected to a metal pipe which runs down the building to
the basement. This pipe is part of the fire extinguish system and is filled with presurized water and in the basement
connects with the main water distribution grid

So this is a 80m pipe which is not just ground but part of the antenna. The high voltaje runs from the coil to the 10m
fiberglass pole and sloppers. But from PA ground to the basement only RF current runs trought that pipe

The result is that the whole pipe is part of the antenna and radiates. So the effective size of the antenna is 80+10m
The performance is very very good. I have not being able to calculate the real radiation resistance, but should be high
And with 3A RF this antenna should be radiating a few watts. That's why my signal is strong

Another important thing is the radiation angle, which should be low, as the building is hight and isolated from others
and also the nearby mediterranean sea can help for a good takeoff to Reunion island, for example

73 de Luis
EA5DOM

А это результат его работы:

http://136.su/index.php/topic,18.msg24947.html#msg24947

http://136.su/index.php/topic,18.msg24937.html#msg24937

Усилитель мощностью 1300Вт


2
Технический раздел / UA4AAV set-up. PA, ANT, LOAD COIL, ect
« : 19 Сентябрь 2019, 22:57:52 »
Коллекивно решили собрать все ссылки по сетапу Виктора в одной теме.

Начиналось всё отсюда:

http://136.su/index.php/topic,74.msg24280.html#msg24280

Power Amplifier./Усилитель мощности:

http://136.su/index.php/topic,74.msg24283.html#msg24283

http://136.su/index.php/topic,74.msg24288.html#msg24288

Fan cooling system/Система охлаждения:

http://136.su/index.php/topic,74.msg24289.html#msg24289

Input  transformer 1:16/Входной трансформатор 1:16:

http://136.su/index.php/topic,74.msg24290.html#msg24290

http://136.su/index.php/topic,74.msg24339.html#msg24339

Anode current.Ток Анода:

http://136.su/index.php/topic,74.msg24293.html#msg24293

Antenna current/Ток антенны:
Maximum on ammeter 25A

http://136.su/index.php/topic,74.msg24294.html#msg24294

Output transformer/Выходной трансформатор:

http://136.su/index.php/topic,74.msg24340.html#msg24340

Circuit diagram/Схема:

http://136.su/index.php/topic,74.msg24338.html#msg24338

Antenna:

http://136.su/index.php/topic,74.msg24286.html#msg24286

Load coil/Удлиняющая катушка:

http://136.su/index.php/topic,74.msg24297.html#msg24297

Bushing/ Проходной изолятор:

http://136.su/index.php/topic,18.msg24849.html#msg24849


3
Помнится, была такая софтина Рика Стробе, которая сама по заданным ссылкам сгружала картинки с грабберов. (Кто знает где скачать - ссылку сюда.) И складывала в архив.
Может у кого-то есть простаивающий старенький комп, И возможность выкладывания ежедневного архива на яндекс-диск или майл-ру облако?
Нужен надежный интернет, чтобы "ни единого разрыва" и компик типа сокет-478, хоть под чем, можно ХП.
Все это запилить в автоматическом режиме вполне реально...
У меня не очень надежный интернет, а то бы может и сам занялся.

4
Посколь RSGB LF накрылась медным тазом с 1 сентября почему-то и не ясны перспективы ее починки, то предлагаю взять у Алана G3NYK список емейлов и позарегать всех тут.
И создать англоязычный раздел.
Сергея спрашивал об этом- но что-то нема ответа пока...
Надо как минимум создать или добавить на существующую страницу регистрации надписи на английском.
Ну и подразделы как  у нас типа на основном.
В дали форум наш не везде хорошо открывается, некоторые жаловались, но другой возможности у нас нет пока.

6
Here are results from the post-processing of yesterdays transmission at
5.17 kHz. RX sites at DK7FC (tree) in 57.6 km distance and DL0AO in 283
km distance. Mixing the two orthogonal loops at DL0AO allowed to steer
the resulting software rotatable loop into and angle where the SNR
became as good as it can be for that day and time. Now the message is
completely readable in 283 km distance (4.8 wavelengths). Two versions
of the result at DL0AO are shown, one from DK7FC.

TX site: 1130m spaced ground electrodes in JN39WI | 1.7 A antenna
current at 370 W TX power (higher losses due to dry soil, thus less
power from the given antenna voltage at the PA)

73, Stefan

Am 03.08.2019 18:08, schrieb DK7FC:

    Свернуть
     BTW today i transmitted "73" in QRSS-240 at 5.17 kHz, starting 08:30
     UTC. There was a team from a TV channel (Bayerischer Rundfunk) at the
     VLF RX site of DL0AO and they followed the QRSS coming in on the
     spectrogram. I hope they will report about it then...
     Unfortunately it took 1.5 hours to fix two broken wires of the
     antenna. Afterwards the QRN already set in, so half the message was
     lost in the noise... Anyway, the 7 is quite doubtless.

     73, Stefan

7
LF: MF Frame antenna
Когда: 4 августа в 12:56
Кому: rsgb_lf_group@blacksheep.org
От кого: Joe df2jp

Hello, folks,

 

since my QTH has changed and the antenna possibilities are rather bad, I decided to build an RX-frame antenna.

During a conversation with Peter, DC0DX on UHF :op it turned out that Peter still had a meander-shaped frame antenna in the corner. the cross has 150cm. In the course of the conversation the question came up: Isn't it also possible to transmit with it? Should work, you only have to add another C to the coupling loop to adapt it to the TX.

Since my frame isn't finished yet, Peter did the first tests at the weekend.

 

2019-08-03 09:24  DC0DX  0.475725  -6  0  JO31lk  0.001  DC5AL-R  JO31lk  0  0
2019-08-03 09:08  DC0DX  0.475725  -28  0  JO31lk  0.001  DC5AL-R  JO31lk  0  0
2019-08-03 08:54  DC0DX  0.475725  -7  0  JO31lk  0.001  DC5AL-R  JO31lk  0  0
2019-08-03 08:38  DC0DX  0.475725  -7  0  JO31lk  0.001  DC5AL-R  JO31lk  0  0
2019-08-03 07:24  DC0DX  0.475725  -19  0  JO31lk  0.001  DC5AL-R  JO31lk  0  0
2019-08-03 07:08  DC0DX  0.475725  -18  0  JO31lk  0.001  DC5AL-R  JO31lk  0  0
2019-08-03 06:38  DC0DX  0.475725  -19  0  JO31lk  0.001  DC5AL-R  JO31lk  0  0



2019-08-02 22:54  DC0DX  0.475725  -20  0  JO31lk  0.001  DC5AL-R  JO31lk  0  0
2019-08-02 22:38  DC0DX  0.475725  -22  0  JO31lk  0.001  DC5AL-R  JO31lk  0  0
2019-08-02 22:08  DC0DX  0.475725  -22  0  JO31lk  0.001  DC5AL-R  JO31lk  0  0
2019-08-02 21:54  DC0DX  0.475725  -27  0  JO31lk  0.001  DC5AL-R  JO31lk  0  0

The two stations are only 5 km apart, transmission power approx. 500 mW, transmission location in the Shack!

Until 08.30 o'clock the loop was directly connected, from then on the 2nd Dreko was added, you can see the difference.

At 09:03 Peter had turned the frame by 90°.

 

Here is a picture of the experimental setup

 

 

I find this very remarkable, considering the holiday and summer time there is hardly anyone qrv on MF, with the loop optimized until autumn some stations should already be added.

 

73 Joe

8
Технический раздел / MT-Hell Standalone
« : 25 Июнь 2019, 23:31:50 »
MT-Hell Standalone

G8HAJ has designed a standalone MT Hellschreiber interface that uses a small 14 pin 16F1615 PIC device.  It can be used either to send a beacon message or inreal time QSO mode using RS232 interface from a terminal.

The speed / bandwidth is made continuously variable from a few 100Hz down to fractions of a Hz using a pot to control the settings.  Which makes it useable at LF

The downside is that it uses a hybrid SMT/CMT which he calls Pol yPhase or PP/MT-Hell type of modulation that does require a linear transmitter - so no high power with a switch mode Tx   

More details and a full description and PIC firmware download at Graham's web site  http://g8haj.uk/    or specifically   http://g8haj.uk/?page_id=288


Four of us using that module recently had a simultaneous full-quadplex (4 way version of duplex :-)  QSO on the QO100 satellite.    A few screen dumps of the QSO underway showing all four stations can be seen here :
http://www.g4jnt.com/DropF/new14.tif
http://www.g4jnt.com/DropF/new18.tif
http://www.g4jnt.com/DropF/new27.jpg
http://www.g4jnt.com/DropF/new29.jpg




Andy
www.g4jnt.com

9
Довольно гениальное изобретение нашего камрада и геноссе Йорга!

Пробил расстояние 70км!

Говорил, что светодиода уже не видно, а демодуляция идёт все равно!
Игрался на расстоянии 150м - уменьшал мощность.

http://dl0rcp.bplaced.de/index.php/themen/48-lichtfunk-lichtsprechen-lichtbaken

14
Широкополосный трансформатор 8.27 кГц-136 кГц-472 кГц 1:1, 1:4, 1:9, 1:16 и 1:25. 1:36

UPD - на всякий случай дискуссия по сему поводу из рсгб:

Hi All
Transformer is ready.
https://klubnl.pl/wpr/en/index.php/artykuly/uniwersalny-nadawczy-autotransformator-antenowy-na-pasma-827khz-136khz-i-472khz/
73! Marcin SQ2BXI

-----Original Message-----
From:
Sent: Friday, February 15, 2019 5:56 AM
To: rsgb_lf_group@blacksheep.org
Subject: RE: R: Re: VLF: in VK?

Hello VLF!
The primary coil of the transformer is ready. 10 turns (diameter 2mm) give 9.62mH which gives about xl=500Ohms at 8.27kHz. It is a good idea!

73! Marcin SQ2BXI

-----Original Message-----
From:
Sent: Monday, February 11, 2019 4:55 PM
To: rsgb_lf_group@blacksheep.org
Subject: RE: R: Re: VLF: in VK?

Hello Stefan!

Today, the ferrite cores B64290L82X830 came to me. I'm building a transformer 1:1/1:4/1:9/1:16 and 1/25 on the VLF. I'll check if it works soon.
73! Marcin SQ2BXI

-----Original Message-----
From:
Sent: Monday, February 11, 2019 2:50 PM
To: rsgb_lf_group@blacksheep.org
Subject: Re: R: Re: VLF: in VK?

Hi Dimitris, VLF,

Am 11.02.2019 01:07, schrieb Dimitrios

    Свернуть
     I have an idea about impedance transformation and that is to use high
     power 70V/100V audio distribution transformers at both ends. I don't
     have to go to 50 ohm as I don't use the coaxial cable as a
     transmission line (it's only a tiny percentage of the wavelength!), so
     I could use a 4 ohm to 400 ohm transformer or similar. I think in
     general the impedance transformation ratio goes down as the power
     rating goes up and we can live with that. THe audio transformer should
     work fine on the higher frequency but that will have to be tested.
     Perhaps something like this but not at that price!!

     https://www.altronics.com.au/p/m1160-300w-100v-line-pa-transformer/

     Another option is to get a PA amplifier of suitable power output that
     has a 70V or 100V output. You only need one transformer at the antenna
     end to get down to 4 ohm to reduce losses. I have a 50 W amp with such
     output but that's not enough power.

These high power audio transformers are interesting. I wonder how well they work below 1 kHz. But they are to expensive, as you say. You don't need them. For any impedance transformation above 1 kHz i use ordinary
N30 ferrite toroids. There may be slightly better core materials but i'm getting very good results and they are not expensive and you can find them at many distributors (min quantity = 1, not 50000000000000000000000000). Especially at VLF they are well suitable and not expensive.
One of my preferred cores is that one:
https://www.buerklin.com/en/ring-core-outer--x-inner--x-height--63-x-38-x-25-mm-n30/p/84d258
It works easily for a few hundret watts on all VLF frequencies.

Yes you don't need to match the cable impedance but the losses on your cable are caused by the current and resistance of the wire and so, if you transform from 4 Ohm to 50 Ohm, then your losses drop by 92 %, regardless if it is necessary to match the cable impedance.

    Свернуть
     I can easily try the ground loop on the 120m long antenna as I do have
     ground rods at both ends. It would be interesting to compare the
     signal strength in both cases. THat's why I am building a network of
     VLF stations by giving away the large ferrite rods to interested
     amateurs! They can help doing comparisons like this.

Yes, sure. Good luck in getting people motivated to build up a permanent VLF RX station. It would also be good to have someone building up a grabber site or maybe even providing a stream. Your activity can cause a world wide motivation for people who are principally interested in VLF reception and/or transmission, even if they won't be able to receive you from so far away.

    Свернуть
     The ground is very rocky and there is almost no soil at the top.
     Typical Australian native vegetation is the only thing that can
     survive on it. I have thought about the dipole on the ground and I
     have the perfect spot for it which is putting the feed point at the
     top of the hill therefore making an inverted-V :-) Only concern with
     that is the high voltage at the end of the dipole wires and the
     possibility of a bush fire ignition. Definitely a project for winter!
     I have tried to tune my ~120 metre wire to VLF in the past with mixed
     results. Worth revisiting this. The wire basically starts at my house
     and follows the hill resulting in the top of the wire being maybe 20
     metres higher than the bottom.

I'm taking part in your experiments by imagining that i would be in your position :-) My latest thought is that a few (wooden?) poles of 10m height or so would be ideal. One is close to the house, and then two more in 100m distance from the house, e.g. here:
http://k7fry.com/grid/?qth=QF44OX00PV&from=QF44OX00LN
The 2x 100m dipole could be connected using a good HF ladder line down to the shack.
Aluminium wire is light weight and cheap and the lower conductivity could be compensated by using a higher diameter, something like this,
https://www.amazon.de/dp/B004UA7XT2
This antenna would have the advantage that you can use it from MF to DC and the kangaroos would not be able to destroy the antenna.
For VLF experiments, the ends of the wire can be grounded, just by adding another 100m of wire at the ends and let them slope down, maybe with another pole at 4m height.


73, Stefan

15
Программное обеспечение / LF: Simple COM port on-off
« : 14 Февраль 2019, 16:00:07 »
примитивная програмка по клацаню релешкой с ком-порта.
может кому будет полезно.

I wrote a couple of progs for someone that simply control RTS & DTR lines on a COM port, so remoted equipment could be turned on or off under PC control

SimpleTimer.exe  turns on at a specified time, then off again at another specified time. and that's it!

ComOnOff.exe toggles the DTR & RTS lines using the + and - kets on the keyboard.  Just a simple manual on-off.

Nothing complicated - but if you use COM port control for turning a Tx on or off they may be usefiul.  Both progs can be found in the folder for the groups.io LF files section
 https://groups.io/g/rsgb-lf-group/files/G4JNT

 
Andy
www.g4jnt.com

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