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Alan,
The only addition I would add , is , a pre -
amp and band - pass filter
Not forgetting , the £5 devices are not
expecting a signal injected directly into
the AD convertor , the gain falls off
past 2 MHz by some 10 may be 15 dB and
there is a image response , same as a
super-het , caused by the sample rate , up in
the HF bands
There are various transformer coupling cct's ,
Ive only ever used a 0.01 uF to the
inter stage coupling cap , a 3
mm surface mount device , makes a good
solder post ..
Works behind a ATU , but a
pre-amp would not go amiss , though data
seems to decode 'as is' the pre amp
ideally would have a out put Z round
200 ohms , other than that , just select
'direct sample' in the sdr set up
box , that turns off the vhf front
and the scales are direct
frequency read out , zero the off set
in the driver and you have a 'good' RX
There are various devices about , but
for £5 gives a good way in , the band
pass filter would benefit any of the
more expensive devices , but as to actual
realisable advantage , post processing , that
might be difficult to evaluate for
data operation , a pre amp would up the noise floor , as
would the band pass filter , first off
try it as is ..
I live not far from BBC radio
Merseyside , multiple qrg Tx , and in a direct
play off .. the £5 dongle gives
better Rx on 80 meters and 160 ,
than the ft897-d , which tends to over
load , neither as good as the ra6790gm lf
[no pre-amp], but that's from a different
drawing office , with 5 to 7 watts drive to
the first mixer
73-Graham
G0NBD
Sent: Wednesday, April 08, 2015 12:40 AM
Subject: LF: Re: HP 3586C selective level meter for LF and
MF
Hi Iban, They do work, but you must realise they
are not intended as radio receivers, and in many aspects their performance as
radios is compromised by their design as line measuring instruments. Problems
include IMD and lack of front end filtering, some lack audio output. Yes you can
get round this or you can be lucky that you location and antenna help
mitigate the problems.
You might be better to consider an SDR these days
but make sure it really cover the frequencies of interest. Graham G0NBD has
information on direct sampling mods to the DVT-B dongles. In Europe there are a
lot more LF signals from very strong stations than in the US so be careful of US
opinions that rate these as receivers. I have a couple of W&G units which
while useful as test equipment are less than brilliant and barely worth
their cost as receivers.
Alan
G3NYK
----- Original Message -----
Sent: Tuesday, April 07, 2015 11:30
PM
Subject: LF: HP 3586C selective level
meter for LF and MF
Hi,
I'm looking to purchase a 3586C. Somebody is using it?
Can give-me feedback about to use in 136 and 477 kHz?
Thanks for advance
73! Iban
eb3frn
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