|
Vintage Amateur and Military Radio Amateur/military receivers and transmitters, morse, and any other related vintage comms equipment. |
|
Thread Tools |
21st Dec 2014, 3:26 pm | #1 |
Pentode
Join Date: Jul 2009
Location: Roxburghshire, UK.
Posts: 196
|
CR300 crystal set
While the fabrication of a PSU for my CR300 is still fairly well down my list of priorities (the bench is still cluttered with HRO carcass), and idly fondling the tuning knob in the passing, it occurs to me that the set has an internal crystal detector for use when everything else has packed in.
Has anyone actually used one of these with the crystal detector? 73. Colin. |
21st Dec 2014, 6:04 pm | #2 |
Dekatron
Join Date: Apr 2011
Location: Cornwall, UK.
Posts: 13,454
|
Re: CR300 crystal set
Ditto with the CR300 I have, nope not tried the crystal detector. I heard it was a Board of Trade requirement back then...True/False ?
Lawrence |
21st Dec 2014, 8:07 pm | #3 |
Retired Dormant Member
Join Date: Apr 2003
Location: Salt Spring Island, BC, Canada
Posts: 368
|
Re: CR300 crystal set
The emergency crystal receiver was a Board of Trade requirement for merchant navy ships. It is 50 years since I tried out the crystal set ( you had to move the top cap lead from the !st RF valve over to a top cap like terminal on the crystal detector.
If I remember right, the detector consisted of a steel flat spring whacking down on a carborundum crystal. I recall that it was very insensitive but would not burn out when the transmitter was keyed. John. |
21st Dec 2014, 8:08 pm | #4 |
Heptode
Join Date: Jan 2008
Location: Birchington Kent, UK.
Posts: 596
|
Re: CR300 crystal set
Hello Colin
the manual says:- |
21st Dec 2014, 10:59 pm | #5 |
Pentode
Join Date: Jul 2009
Location: Roxburghshire, UK.
Posts: 196
|
Re: CR300 crystal set
One feels the need to try with a germanium diode - I can't see carborundum being up to much but probably enough to work another ship a few miles away. I guess they used mcw or would the sparkers be expected to read clicks and ac hum?
|
21st Dec 2014, 11:51 pm | #6 |
Retired Dormant Member
Join Date: Apr 2003
Location: Salt Spring Island, BC, Canada
Posts: 368
|
Re: CR300 crystal set
We used MCW and on my first single operator ship we had a spark transmitter for a back up.
The crystal set could use the ships main transmitting aerial, Some 200 ft long and about 80 ft high. The ground was the best ever, the steel hull of the ship in salt water. John. |