Hello

I have just picked up this tuner and wonder if anyone can supply a copy of the owner's manual or any other documentation that is available.

The unit appears to be missing a loop antenna which swivels at the back. Can rig this up easily enough but would like to know what it looks like.

When you do make an antenna, you can optimize the number of turns by tuning in a station at the low end of the AM band, say at 558kHz, and adding or removing turns to get maximum signal strength.

Thanks Wa2ise.
I will try an old ghettoblaster stick that I have first. But the tuner will operate in my study with computer, printer, modem, router etc so I think eventually I will need an air wound loop placed outside the room tuned with an old tuning capacitor, especially as the stations I want to tune to are about 50 miles away.

The AM antenna input has an antenna and earth terminal so I am not sure if it is a balanced input for a loop.

I can't find info on the T-420A, but I have an R-700 tuner-amp with a swivel type loop antenna on the rear. I don't know if it's of any assistance but here is a scan of the R-700 sales brochure showing what the antenna looks like:

http://i169.photobucket.com/albums/u218/gtc_photos/Radio%20stuff/R-700loopantenna.jpg.

Thanks for the link GTC.

The loop in the link looks too tall for my tuner (~60mm high).

I found a pic of another Yamaha AM stereo tuner which had a tuneable loopstick on the back (four wire going into it).
However there are only two AM aerial terminals on my tuner so loop not tuneable.

I tried it out with a loopstick with an old tuning cap and pulled in strong AM signal from Sydney 80k away - but no sign of stereo on ABC 702, 2SM, 2CH, 2GB.

I have now got it working in my study with an untuned air loop of several turns of wire a metre away from the computer. 60% signal strength, a bit noisy but OK for talk shows.
Stations tune across three positions eg 702 from 693 to 711 so selectivity doesn't look too good. I wonder if the loop should be multi strand litz wire for high Q to improve selectivity.

Now to put a tuneable loop outside.

Mine is 70mm x 145 mm (two wire).

Re: "but no sign of stereo on ABC 702, 2SM, 2CH, 2GB" did you really mean stereo for those AM stations?

Here's an article in Silicon Chip that may be of interest:

http://www.siliconchip.com.au/cms/A_111084/article.html.

and

http://secure.oatleyelectronics.com/files/K256notes.pdf.

Don't forget there are stations that did transmit in stereo that do so no longer. When the availability of stereo receivers fell by the wayside many stations did away with the expense of stereo transmissions when they did future equipment upgrades.

This is to say that studio consoles are still two channel but the actual transmitters aren't.

Yes, I recall the stereo AM experiment, although I didn't bother with it.

GTC

I like the look of the remotely tuned loop in the second article - thanks

Yes, I recall the stereo AM experiment, although I didn't bother with it.

I couldn't afford it at the time.

I'm glad that digital radio is more accessible.