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	<PAEFLMFGBDKKCONLMLBIIEKCEBAA.ganymede444@btopenworld.com>
Date: Wed, 3 Jul 2013 09:10:33 +1000
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From: Dimitrios Tsifakis <dtsifakis@gmail.com>
To: rsgb_lf_group@blacksheep.org
Subject: Re: LF: WSPR-2 on 630m last night
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Status: O

Hi Dave,

There are no problems here operating portable on 630m. The only
problem with portable operation is that it is hard to provide a low
impedance ground system. At home, I have a number of copper plated
rods and the impedance of my antenna is about 20 ohm, which is great.
When /P though, this figure is always much higher, and that ain't
because the radiation resistance has gone up miraculously ;-)

By the way, I am always amazed by the distance covered by such low
radiated power. Surely this has to do with 630 m but also with the
WSPR protocol. I routinely reach Tasmania, Brisbane and Adelaide with
my low power beacon, and the are all just shy of 1000 km away. I have
also reached a station in Alice Springs, right in the middle of the
country, and that's closer to 2000 km. If there were more listeners
further away, I am sure they would report reception too.

73, Dimitris VK1SV


2013/7/3 Dave G3WCB. <ganymede444@btopenworld.com>:
> Hi, Dimitris, LF.
>
> Thanks for posting an interesting article on QRP WSPR. I've been
> experimenting along similar lines, but in my case I'm using a QRP Labs
> Ultimate 2 kit, which uses the same DDS as your TX, but the WSPR is
> generated by an ATmega168 AVR microcontroller. No PC necessary.
>
> With an RF output of about 2 watts into a 5m high "tee" antenna with a 20=
m
> top, I've been consistently spotted at 363km range during darkness by PA3=
ABK
> and PA0A at 499km, with just one spot by DG3LV at 791km range.
>
> My ultimate aim is to assemble a portable WSPR station and hike out to a
> remote location, for example Dartmoor, in Devon. I'll need to check to se=
e
> if the terms of my licence NOV allow portable operation on 630m first ;-)
>
> 73, Dave G3WCB IO91RM
>
> -----Original Message-----
> From: owner-rsgb_lf_group@blacksheep.org
> [mailto:owner-rsgb_lf_group@blacksheep.org]On Behalf Of Dimitrios
> Tsifakis
> Sent: 02 July 2013 00:39
> To: rsgb_lf_group@blacksheep.org
> Subject: Re: LF: WSPR-2 on 630m last night
>
>
> Hi Stefan,
>
> VK dominates WSPR in numbers but not in records -  yet!  :-)
>
> I have been busy with university homework but that's finishing now, so
> I will get busy with radio again. My latest experiment is a very
> simple WSPR-2 Arduino/DDS/Class-E transmitter. The web page below is
> work in progress:
>
> http://people.physics.anu.edu.au/~dxt103/472/wspr_tx/
>
> I have also been doing some tests with a very restricted antenna just
> to prove the point that a super large antenna is not the only way to
> enjoy the new low bands. Last weekend I did a quick test with the WSPR
> beacon from my block of land outside Canberra, using the earth dipole
> antenna. I was able to cover 180 km with only 5 W and I know what to
> do to improve this. Can't beat a ground antenna when it comes to
> convenience!
>
> 73, Dimitris Vk1SV
>
> 2013/7/2 Stefan Sch=E4fer <Stefan.Schaefer@iup.uni-heidelberg.de>:
>> Hi Dimitris,
>>
>> Am 01.07.2013 06:02, schrieb Dimitrios Tsifakis:
>>
>>> Not only it's winter, but I noticed that VK dominates WSPR on 630m on a
>>> regular basis :-)
>>
>> Are you sure? :-)
>>
>>
>>> There are plenty of stations monitoring, from all over the country,
>>> including, from time to time, one from Perth, Western Australia.
>>
>> Yes, i see. It is very nice to see so much activity from down under. But
>> where are all the ZL stations?
>>
>>
>>> So far, we haven't managed to repeat the VK1DSH->F6CNI record but
> perhaps,
>>> if the activity keeps to a high level, it's a matter of time until an E=
U
>>> station is received here.
>>
>> That was a very rare event i guess. But we'll try. Thanks for the
>> motivation. BTW soon the LF DX season starts again and Edgar has done a
> lot
>> of effort to prepare for a new #3 DX WR on LF. I'll try to transmit as
> much
>> as possible, either on MF or on LF. Actually i should really build an
>> automatic antenna switch. Then i can send a MF WSPR 2 block between the
> gap
>> of 2 LF DFCW-180 elements :-)
>>
>> Have fun and good luck!
>> Any new /p experiments from your side? And how does the tube PA perform
> now?
>>
>> 73, Stefan/DK7FC
>>
>>>
>>> 73, Dimitris VK1SV
>>
>>
>
>