Welcome to Australia's only Vintage Radio and Television discussion forums. You are not logged in. Please log in below, apply for an account or retrieve your password.
Australian Vintage Radio Forums
  Home  ·  About Us  ·  Discussion Forums  ·  Glossary  ·  Outside Links  ·  Policies  ·  Services Directory  ·  Safety Warnings  ·  Tutorials

Tech Talk

Forum home - Go back to Tech talk

 Lazy oscillator, AWA 453-P continued
« Back · 1 · Next »
 Return to top of page · Post #: 1 · Written at 6:45:06 AM on 6 January 2014.
Simplex's Gravatar
 Location: Bathurst, NSW
 Member since 7 August 2008
 Member #: 336
 Postcount: 391

Good progress has been made with the rebuild of this set (please refer my other thread) and thanks for the contributions from members which were of great assistance.

The set is very lively on the broadcast band and cannot complain of its receiving ability which is quite surprising.

Shortwave is a sad story, the set covers 6 to 18MHz. Made up a primitive loop on a piece of cardboard and fed this to my signal generator.

Chose 10MHz as roughly the centre of the band and even with the generator as max output (10mV) could barely pick the signal up.

Unfortunately do not have an oscilloscope so with a GDO in diode detect function put the GDO coil near the osc coil and get full scale deflection on the GDO.
So at 10MHz the osc is running strongly, get similar results with higher frequencies.

However at frequencies below 8MHz the osc stops oscillating completely.

Tried a careful adjustment of the oscillator trimmer cap along with r.f coil trimmer with no change.

Despite the above in the evening connected a aerial wire of about 3 or so metres (this set needs a wire aerial on shortwave) and managed to hear Radio Japan just below 10MHz as well as a swarm of Chinese mainland stations around 12 to 14MHz.

Signals were listenable with fades and clearly judging by the sets broadcast performance could do better I think.

Any suggestions welcomed.


 
« Back · 1 · Next »
 You need to be a member to post comments on this forum.

Sign In

Username:
Password:
 Keep me logged in.
Do not tick box on a computer with public access.