DCF 77 77.5KHZ

Useful information regarding antennas for SDR products.
Paul
Posts: 355
Joined: Fri Feb 17, 2017 9:52 am
Location: SW UK

Re: DCF 77 77.5KHZ

Post by Paul » Tue Jul 23, 2019 5:34 am

G'day from SWUK
Have a look at this and follow the thread back if so inclined.
This member Gianfranco in Italy and his mate Phil in Tassie are (obviously) extremely knowledgable and experienced, frequently swapping technical data, including diagrammes and tables etc back and forth.
However, they are not above offering advice and guidance at levels that the likes of me (low-tech grunt) can understand and are really human and helpful.
This item may whet your appetite to give consideration to loop antennae as enthusiastically promoted by Phil.

https://www.sdrplay.com/community/viewt ... =30#p16052

As an aside, although living in a rural location, I have some space constraints, have a 20M longwire, an active mini-whip and a mag-loop (Wellbrook), used among other things for NDB "hunting" (furthest to date
at 6534KM from me, so you never know...

Success and best wishes.
Paul
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g1hbe
Posts: 494
Joined: Sat Jan 17, 2015 3:28 pm
Location: Cheshire, UK

Re: DCF 77 77.5KHZ

Post by g1hbe » Tue Jul 23, 2019 9:39 am

Generally speaking, if you have a low local noise level, wires and active mini-whips should work well. but if your noise level is high (like most of us these days), an active loop such as the Wellbrook 1530 will be the best. If you have the ability/skill to build an amplified loop you can save a lot of money.
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Andy

glovisol
Posts: 662
Joined: Thu May 10, 2018 6:42 pm
Location: Piedmont, Italy

Re: DCF 77 77.5KHZ

Post by glovisol » Tue Jul 23, 2019 5:06 pm

Hi VK3MHz,

Perhaps the thread below on my adventures with a 160 m long Beverage antenna could be of help.

https://www.sdrplay.com/community/viewt ... f=8&t=4493

What is notable in this thread is that I proved that to obtain remarkable low noise operation you must forget about stake ground as the antenna return, so, in this respect large loops are very much convincing, being balanced windings literally floating in space and are, with a low noise transformer in between, the natural complement to the HI Z input of the RSP2 or the RSPduo.

So, following my recent exchanges with Phil, vk3jj, where, being in a small flat at the sea side, I started testing 0.8 to 1.3 square meters loops on suggestions by Phil, I realised that most probably a large square loop with a side length of 40 to 60 m might be the high aperture/low noise solution any listener is hoping for, so I am going to build this antenna as soon as I get home in August.

https://www.sdrplay.com/community/viewt ... f=8&t=4698

After my experience with a non-amplified small loop, I fully agree with Andy, g1hbe, that an active loop is the best solution when you do not have space to spare. For limited space another solution is a "big" ferrite loaded antenna, made with an array of long ferrite bars (expensive!) assembled into a big core and wound with litz wire: we are talking of LF, of course.

Kind regards,

glovisol
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VK3MHZ
Posts: 41
Joined: Sun Apr 30, 2017 7:24 am

Re: DCF 77 77.5KHZ

Post by VK3MHZ » Thu Jul 25, 2019 3:44 pm

Thanks to those who replied.

Space - As I said previously, not really any issue.
Noise - Again not an issue.
Height - Only problem as previously said.

Should I look at a vertical antenna, or is horizontal sufficient. Keep in mind the goal is to receive some European LW broadcast stations, if at all possible.

I really don't want to be purchasing antennas, as most of these come from overseas, depending on country of origin freight can be horrendous, not to mention exchange rates. I don't have a lush bank account to throw money at high-end antennas, or even low-end expensive antennas. So I would prefer to make something simple myself.
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ernestyn
Posts: 18
Joined: Mon Jul 22, 2019 1:40 pm

Re: DCF 77 77.5KHZ

Post by ernestyn » Sat Aug 03, 2019 4:56 pm

Dear VK3MHz,

I am glad you wish to experiment antennas for lower frequency reception from far away. If you experiment with the Langford antenna, very easy and simple and cheap to make look up the post of SDRguy22 in this section we can get your results in reception and then make more perfection to complete capacitor antenna for wideband and lowest noise.
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VK3MHZ
Posts: 41
Joined: Sun Apr 30, 2017 7:24 am

Re: DCF 77 77.5KHZ

Post by VK3MHZ » Mon Aug 05, 2019 8:19 am

ernestyn wrote:
Sat Aug 03, 2019 4:56 pm
I am glad you wish to experiment antennas for lower frequency reception from far away. If you experiment with the Langford antenna, very easy and simple and cheap to make look up the post of SDRguy22 in this section we can get your results in reception and then make more perfection to complete capacitor antenna for wideband and lowest noise.
I was unable to find this post, from memory there were a lot more posts in this thread prior to the board being placed in moderation mode, so it may have being axed, unless I am looking in the wrong place!

[Edited] Admin explained via email. Thanks guys.
Last edited by VK3MHZ on Tue Aug 06, 2019 6:10 am, edited 1 time in total.

ernestyn
Posts: 18
Joined: Mon Jul 22, 2019 1:40 pm

Re: DCF 77 77.5KHZ

Post by ernestyn » Mon Aug 05, 2019 3:19 pm

Dear VK3MHz,

the post is:

viewtopic.php?f=8&t=4788
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VK3MHZ
Posts: 41
Joined: Sun Apr 30, 2017 7:24 am

Re: DCF 77 77.5KHZ

Post by VK3MHZ » Mon Aug 05, 2019 4:32 pm

ernestyn wrote:
Mon Aug 05, 2019 3:19 pm
Dear VK3MHz,

the post is: viewtopic.php?f=8&t=4788
Thanks mate.
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