Vintage Hallicrafters SX-100 Mark 1B Shortwave Receiver: Restored and Final Tests

In this episode the finished shortwave receiver is tested for drift rate, audio response, minimum discernable signal (sensitivity), and S-meter response.

[@charleslauter5035]

Very nice set of measurements that most people do not understand. CAL

[@i82996]

If I say its good I want to prove it. Hopefully others will learn what I learn, and if something I say is wrong then we all learn more.

[@tomstafford1605]

I am sorry to hear about your dad. Thanks for putting together these in depth videos. I am sure they will help many people as they work on these great old receivers.

[@i82996]

You are so kind.

[@mirrar01]

Very nice video. I recently got an SX-100 mk1 that was in pretty rough condition. I've recapped it, aligned it a bit, but pretty much left the cabinet original/ rusty.

[@i82996]

Thanks for sharing!

[@mikemurray1517]

I really think your videos are full of excellent info, especially since I'll soon be starting an SX-100 restore. HOWEVER, the audio seems to have gotten even worse with this one and I can hardly understand it even with my aux. amp turned all the way up.

[@i82996]

I am sorry Mike about that. I mike checked before every take and it sounded ok in the camera. Will try a different configuration. Obviously i dont get cinemetography (sp?) awards

[@i82996]

Take your time and go slow. Be sure and open up both subchasses and check resistances. The IFs most likely will dc check out and you shouldnt need to open them.

[@mikemurray1517]

@@i82996 Thanks for the tip!

[@charleslauter5035]

You are using 50 Ohm generator, cables, and attenuators. But what is the input impedance of the SX-100? CAL

[@i82996]

I did not discuss but the AF generator is set to 50 ohm impedance. Recognizing that the actual antenna A1 and A2 are designed for 300 ohm impedance from a twin lead dipole, hardly anyone uses such an antenna anymore. All normally use a 50 ohm coax feed through an antenna matching box to a balun to an added on SO-259, so all my RF alignments (RF and Antenna) coil adjustments are at 50 ohm and the antenna compensator is adjusted for maximum as well. Trying to use an impedance match from a coax to A1 and A2 has never been successful for me and my results using the SO-259 jack (direct to A1 and A2 grounded) has been very successful in all circumstances.

[@i82996]

I love good questions.

[@mirrar01]

Does the sx-111 share the same as the sx-99, or is it higher quality like the sx-100?

[@i82996]

I saw one NP0 on the RF on the schematic and two N330’s on the oscillator switch. The oscillator section is considerably different on a Ham receiver than a general coverage receiver so I cannot tell how stable it is just from a schematic.