| I can't find the initial posting for this, but the replies seemed to have generated a small library of references. May I add a few points from my early days on above-ground LF, please?
The old saying “if you can't hear them you can't work them” still applies. My first efforts at receiving used a 1 m diameter loop resonated at about 136 kHz, feeding a Lowe HF 250 or sometimes a Datong up-converter and a Sony 2000D. In Suffolk, these enabled me to receive G3KEV at good strength and to confirm somebody's adage (Alan?) “If DCF39 isn't S9 plus a lot your receiver may be somewhat deaf”. For displaying signals on screen I have found Argo is a very good program.
When you come to transmit, there is quite a bit to learn about antenna construction, matching and so on. This of course applies on any band.
With a vertical of about 8 m height, about 2 x 30 m of horizontal loading, and a feed current of about 400 mA (estimated ERP about 2 mW) I achieved a range of about 200 km from my QTH in Burgundy. To do all this, it helps to have means of measuring RF current and impedance at the working frequency. Although I did not find it vital for my initial experiments in transmission, a Scopematch was very useful to check that the antenna was near Wrexham [whoops! - resonance. Thank you, Macspeech. Always check your dictated e-mails before you send them].
73 John F5VLF/G3PAI
On 2 May 2012, at 01:23CEST, Alan Melia wrote: You still need a receiver and aerial that work !! :-)) Alan ----- Original Message ----- From: "Graham" < [email protected]> To: < [email protected]> Sent: Wednesday, May 02, 2012 12:11 AM Subject: Re: LF: Basic LF understanding Is there maybe something for receive newcomers?
Of course !!,
The New windows based , user friendly , Opera Beacon & QSO mode ,
simply install , set the dial to 136/500 KHz usb , add any old aerial and
watch the local decodes of stations on the left side and other
monitors on the right side , while keeping an eye on the PSK-Reporting
map for new Tx stations http://pskreporter.info/pskmapn.html,
No internet time locking , No high stability oscillators and No need
for guessing who you have decoded ! (unless its very good dx , then
its more likely its Mr Noise playing tricks !) works with or without
internet connection.
The only real traditional CW data mode combining on-off keying
with state of the art Digital Signal Processing , in fact on/off keying has
not been so much fun since Jean-Antoine Nollet first shocked the
world in 1746 , a hundred years or so before this new fangled Morse code
'adopted' the idea !
As one Op32 user reported after sending a 50 watt beacon ........
''Just got a report from Harry PA3BHT, who is at 174 km from me.
He had seen that I was going on OP32 beacon and put his Opera on OP32
mode.
BUT he had not attached his outside antenna!! HI.''
The report was:
20:45 136 PA0OCD de PA3BHT Op32 174 km -39 dB in DELFZYL with 50w + 6 m
Vert + T
G :))
--------------------------------------------------
From: "Stefan Schäfer" <[email protected]>
Sent: Tuesday, May 01, 2012 9:53 PM
To: <[email protected]>
Subject: LF: Basic LF understanding
LF!
Has someone a very good link to basic understanding about LF? I mean the
LF amateur radio stuff, all which one has to learn when starting rx-wise
in our hobby! Maybe some ideas and examples, a good compliation. Not to
complex and focusing on 137 kHz amateur radio?
For newcomers in the "LF-transmit-world" i recommend ON7YD's page
http://www.strobbe.org/on7yd/136ant/
Is there maybe something for receive newcomers?
A collection of some links may help as well...
Thanks in advance.
73, Stefan/DK7FC
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