Shortwave aerial - Page 2 - UK Vintage Radio Repair and Restoration Discussion Forum

Keith · 28th May 2017, 7:56 pm

Quote:

The subject of antennae has been well-infused with all sorts of strange beliefs (and in some cases the very highest purity of snake oil) for over a hundred years.

Quite so - remember the Joystick...?

peterpiper · 29th May 2017, 3:01 pm

Hi again all, talking about aerial anomalies, I,m currently using a loop of 3mm copper around a PVC window frame containing 2 double glazed units, both with aluminium strip all round the edges. I didn't notice this till I had the aerial up and running and giving similar signal to the Wellbrook. I thought that 2 shorted turns inside the loop was bound to affect it. I tried moving the loop away from the window frame, no effect, no expected increase in signal. Snake Oil, maybe!

Peter

G8HQP Dave · 29th May 2017, 5:52 pm

Aluminium is a poorer conductor than copper, and the joints may not have been made with low electrical resistance in mind.

David G4EBT · 29th May 2017, 8:33 pm

Quote:

Originally Posted by peterpiper

The pre amp used was a 2 transistor version of the Gary Tempest design.

Peter

That's the basic "Simple Active Receive Loop Antenna" design by Dutch radio amateur PA1M, which inspired Gary to develop his own design using five 2N5109 transistors.

http://www.pa1m.nl/pa1m/simple-active-receive-loop/

As PA1M explains: "The schematic above is a look-alike from the 1984 design of John G8CXQ (G4UAZ). An improved design from G8CXQ has been published by Des M0AYF:

http://www.qsl.net/m0ayf/active-loop...uit_diagram_is

PA1M now uses a more complex design by LZ1AQ which appears to be available as a kit:

http://www.pa1m.nl/pa1m/lz1aq-actiev...ne-versterker/

Anyone who is interested in learning more about Gary Tempest's well tried and tested 'amplified magnetic loop receiving antenna' might like to know that Gary has posted full details at the link below, (where Gary is known as 'Radio Fixer'). It runs to nine pages and more than 20 pictures, outlining Gary's R&D behind the finished design, and full constructional details, followed by a two-page evaluation:

http://golbornevintageradio.co.uk/fo...d.php?tid=5944

Hope that's of interest and use.

Radio Wrangler · 29th May 2017, 9:04 pm

They seem only to be available to logged-in members of that group.

David

29th May 2017, 3:01 pm	#22
peterpiper Tetrode Join Date: Jul 2016 Location: Renfrew, Renfrewshire, UK. Posts: 93	Re: Shortwave aerial Hi again all, talking about aerial anomalies, I,m currently using a loop of 3mm copper around a PVC window frame containing 2 double glazed units, both with aluminium strip all round the edges. I didn't notice this till I had the aerial up and running and giving similar signal to the Wellbrook. I thought that 2 shorted turns inside the loop was bound to affect it. I tried moving the loop away from the window frame, no effect, no expected increase in signal. Snake Oil, maybe! Peter

29th May 2017, 5:52 pm	#23
G8HQP Dave Rest in Peace Join Date: Sep 2008 Location: Solihull, West Midlands, UK. Posts: 4,872	Re: Shortwave aerial Aluminium is a poorer conductor than copper, and the joints may not have been made with low electrical resistance in mind.

29th May 2017, 9:04 pm	#25
Radio Wrangler Moderator Join Date: Mar 2012 Location: Fife, Scotland, UK. Posts: 22,868	Re: Shortwave aerial They seem only to be available to logged-in members of that group. David __________________ Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done