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Message-ID: <RKNytmEt0SLGFwYK@g3xaq.demon.co.uk>
Date: Mon, 23 Apr 2007 23:03:25 +0100
To: rsgb_lf_group@blacksheep.org
From: Alan Ibbetson <alan@g3xaq.demon.co.uk>
References: <000a01c785dd$456ebba0$79e8fc3e@g3kev>
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Subject: Re: LF: 500 EASY START
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Hello everyone, Alan G3XAQ here. I just joined this mailing list. I'm 
preparing my application for a 501KHz NoV, so Mal's note on an easy 
start is very timely.

For me, there is an even easier route to getting on 600m in that I 
already have a 3 stage transmitter with plug in coils. The only problem 
is I will need a fundamental crystal somewhere in the band. Quartslab 
don't seem to do LF crystals. Does anyone know of a supplier?

Is there an archive anywhere of the aerials folks are using? I'm 
thinking of pressing my 15m high 160m inverted-L into service. The 
vertical section runs quite close to my tower and I was wondering if 
it's worth end loading the wire with a coil, part way along the 
horizontal section, just to get the high voltages away from the tower? I 
know that going from triangular to uniform current distribution (below 
the coil) will raise the radiation resistance 4 times, but since we are 
being licensed on ERP this just means I will need half the aerial 
current. My motivation is tower coupling loss minimisation, seeing as I 
can't measure it, not absolute efficiency. Mind you, all this ERP stuff 
seems a bit bonkers and quite unlike the usual ham licensing approach. 
Who can measure ERP with any accuracy? Why not just give us the usual 
stipulation of tx power at the feedpoint and leave it to all of us to 
make the most efficient aerials we can?

What is de rigeur for the receive aerial? Does everyone use the transmit 
aerial, or should I be thinking about a medium wave DXer's tuned loop?

Sorry for the dumb questions. There doesn't seem to be much on the web 
that is useful for amateur sized gardens. My Services Textbook of Radio 
vol 5 suggests that for MF I should begin by erecting a 100m tower...

I hope to get the NoV application off by the weekend. See you all on the 
band soon.

Alan G3XAQ

In message <000a01c785dd$456ebba0$79e8fc3e@g3kev>, hamilton mal 
<g3kev.ham@virgin.net> writes
>Hi All
>An Easy Start solution for 500 is to use an existing HF rig modified for 5
>mhz tx at low power, then shape the sine wave to sq wave  with a single chip
>and divide by 10 with another chip then a driver chip to a fet pa, then lpf
>and you are in business. A single fet class E pa is sure fire and so simple
>to build. Mine went first time.
>My solution for an exciter is an IC 706 on 5 mhz and also used on 13.7 mhz
>for LF used. This is a vy stable sig source.
>If anyone needs more info about type of chips etc let me know.
>73 de Mal/G3KEV
>
>
>

-- 

Cheers,

Alan G3XAQ
alan@g3xaq.demon.co.uk