Message-ID: <5716079B.30004@lineone.net>
Date: Tue, 19 Apr 2016 11:25:31 +0100
From: LineOne <dhchurch@lineone.net>
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To: rsgb_lf_group@blacksheep.org
References: <5713E677.6040003@lineone.net> <1071555453.20160418034309@chriswilson.tv>
In-Reply-To: <1071555453.20160418034309@chriswilson.tv>
Subject: Re: LF: Alex (R7NT) reports
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Status: O

For LF reception there's no great secret. A decent communications 
receiver tuning down to 30kHz combined with a wire  aerial broadly (or 
sharply) tuned to 136kHz, a correct loading coil should do the same job, 
this reduces broadcast signals to more acceptable levels.
The receiver should have no attenuation below (say) 550khz, most of them 
have a bandpass filter on the front end, the older ones with a tuned 
front end were good but not stable enough. If you can get a circuit of 
the front end and re-draw it in a software program such as Tina it will 
display the frequency response and allow modifications to be set. I 
altered one inductor only. Beware of the remaining stations on Long 
Wave, it may require a notch filter, this is where software helps again. 
I think many transceivers for Amateur use have very poor, mediocre or 
just average receiver response at LF so I'm not sure if a preamplifier 
would help unless it's tuned.
A notch filter on the receiver is essential and a good USB filter as 
well. It's worth buying extra filters according to the receiver as 
supplied. There is some choice but an internet search may help.

Hugh, M0DSZ

> Hello Hugh,
>
> Sunday, April 17, 2016
>
>    Likewise, many thanks to Alex, it is a generous and useful service,
>    and I look forward to seeing who heard who. Thanks Alex!!
>
>    BTW  Hugh,  may  I ask what you are using for LF reception please? I
>    want  to  get  a better RX setup here, it isn't very good compared to what
>    you are achieving. Thanks.
>
>
> Best regards,
>   Chris  2E0ILY                          mailto:chris@chriswilson.tv
>
>
>
>> I must thank Alex (R7NT) for his carefully collated, weekly reports, it
>> helps to coordinate everyone's LF tests. For some reason I haven't been
>> receiving him well or often though there are times when I'm not in Rx
>> mode by virtue of being on HF fro a while, especially on Sunday mornings.
>> Hugh, M0DSZ
>
>
>