Canadian HF receiver - UK Vintage Radio Repair and Restoration Discussion Forum

Mike-repairman · 10th Jan 2019, 3:19 pm

Clearing out an old cupboard I found a photo of my old Canadian receiver but can't remember what the model was or the manufacturer.
The only memory I have of it was that the local oscillator on one band was near to the IF of the old 405 line TVs and even with double screening in the case and chassis it could wipe out half the TVs in the street; I only used it in the daytime when the only program transmitted was the test card.
Anyone recognise it; wishing in a way I'd kept it.

M0SOE_Bruce · 10th Jan 2019, 6:29 pm

It's a Vancouver Radio Laboratories (VRL) model 250, made during WW2 for the Canadian Army. I still have mine.

Mike-repairman · 10th Jan 2019, 6:43 pm

Many thanks M0SOE_Bruce; I think they were fairly rare at the time; never seen another.
Mike.

G6Tanuki · 10th Jan 2019, 6:44 pm

That LO-leakage issue was common with the old National HRO too: on 14MHz the 3rd harmonic of the LO landed right on top of 405-line London BBC TV.

Mike-repairman · 10th Jan 2019, 6:46 pm

Yes, G6Tanuki; I could never believe how strong the escaping signal was.
Mike.

turretslug · 10th Jan 2019, 7:49 pm

Intriguing- Radiomuseum has it down as 18 valves (including magic eye and rectifier) with single conversion, yet it boasts 2x 6L7 and 2x 6K8 valves. Perhaps one of these might be a product detector, another a dividing calibrator?

M0SOE_Bruce · 10th Jan 2019, 8:44 pm

The manual says 19 valves which is odd as for a Canadian receiver it should have said 19 tubes.

turretslug · 11th Jan 2019, 3:14 pm

Quite a sophisticated set for the era then- a 6L7 as noise-gated 3rd IF amp and no less than 3 valves in the calibrator. Interesting that they provided a 10kHz marker option, at least this would have meant that the receiver could stand alone without the need for wave-meters or painstakingly made and high-resolution individual logging charts. Wonder what the rationale was behind using the other 6L7 as 2nd RF amp? Perhaps calibrator injection.

10th Jan 2019, 3:19 pm	#1
Mike-repairman Heptode Join Date: Jun 2008 Location: Cambridgeshire, UK. Posts: 613	Canadian HF receiver Clearing out an old cupboard I found a photo of my old Canadian receiver but can't remember what the model was or the manufacturer. The only memory I have of it was that the local oscillator on one band was near to the IF of the old 405 line TVs and even with double screening in the case and chassis it could wipe out half the TVs in the street; I only used it in the daytime when the only program transmitted was the test card. Anyone recognise it; wishing in a way I'd kept it. Attached Thumbnails

10th Jan 2019, 6:29 pm	#2
M0SOE_Bruce Pentode Join Date: May 2013 Location: Deal, Kent, UK. Posts: 139	Re: Canadian HF receiver It's a Vancouver Radio Laboratories (VRL) model 250, made during WW2 for the Canadian Army. I still have mine. Attached Thumbnails

10th Jan 2019, 6:43 pm	#3
Mike-repairman Heptode Join Date: Jun 2008 Location: Cambridgeshire, UK. Posts: 613	Re: Canadian HF receiver Many thanks M0SOE_Bruce; I think they were fairly rare at the time; never seen another. Mike.

10th Jan 2019, 6:44 pm	#4
G6Tanuki Dekatron Join Date: Apr 2012 Location: Wiltshire, UK. Posts: 13,996	Re: Canadian HF receiver That LO-leakage issue was common with the old National HRO too: on 14MHz the 3rd harmonic of the LO landed right on top of 405-line London BBC TV.

10th Jan 2019, 6:46 pm	#5
Mike-repairman Heptode Join Date: Jun 2008 Location: Cambridgeshire, UK. Posts: 613	Re: Canadian HF receiver Yes, G6Tanuki; I could never believe how strong the escaping signal was. Mike.

10th Jan 2019, 7:49 pm	#6
turretslug Dekatron Join Date: Nov 2011 Location: Surrey, UK. Posts: 4,394	Re: Canadian HF receiver Intriguing- Radiomuseum has it down as 18 valves (including magic eye and rectifier) with single conversion, yet it boasts 2x 6L7 and 2x 6K8 valves. Perhaps one of these might be a product detector, another a dividing calibrator?

10th Jan 2019, 8:44 pm	#7
M0SOE_Bruce Pentode Join Date: May 2013 Location: Deal, Kent, UK. Posts: 139	Re: Canadian HF receiver The manual says 19 valves which is odd as for a Canadian receiver it should have said 19 tubes. Attached Thumbnails

11th Jan 2019, 3:14 pm	#8
turretslug Dekatron Join Date: Nov 2011 Location: Surrey, UK. Posts: 4,394	Re: Canadian HF receiver Quite a sophisticated set for the era then- a 6L7 as noise-gated 3rd IF amp and no less than 3 valves in the calibrator. Interesting that they provided a 10kHz marker option, at least this would have meant that the receiver could stand alone without the need for wave-meters or painstakingly made and high-resolution individual logging charts. Wonder what the rationale was behind using the other 6L7 as 2nd RF amp? Perhaps calibrator injection.