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Fun little receiver BC 728 C




 
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Author Topic: Fun little receiver BC 728 C  (Read 1428 times)
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PA0NVD
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Nico and Chappie (Chappie is the dog...)


« on: March 19, 2018, 05:32:33 PM »

I could remove this receiver from my sea container, it was at the entrance, and made some pics. For the people who don't know it, it is a single superhet  tuning 2 - 6 MHz in 4 bands. The selected frequency becomes a preset channel in that band that you can select with a push button switch. It is powered by a single 2 volt lead acid cell that can be charged from various voltages using a vibrator down converter to 2 1/2 volts A second vibrator is used to generate the HV
The set has a large whip antenna and is quite sensitive, the received band noise is many dB stronger than the receiver noise and can be used to tune the RF amp input and output circuit without a signal present.
You can imagine that I tuned the third band to 3705, AM  Smiley
In Holland I used it a lot to receive the AM net.  The last 20 years it was stored in Spain (where is much less AM activity) and I bought a 2 Volt cell for it before moving to CR
Here I switched it on and it worked immediately and was still tuned correctly, and that after approx 22 years of storage.
Coming days I will listen if I can hear some AM at 3705


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KE5YTV
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« Reply #1 on: March 19, 2018, 08:27:11 PM »

That's an interesting receiver. I've haven't come across one before. Thanks for sharing.
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Mike
KE5YTV  Dallas, TX
"The longest trip begins with a stop at the ATM."
WB6NVH
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WWW
« Reply #2 on: April 22, 2018, 05:37:43 AM »

It was a portable set intended to serve as a warning alarm receiver for gas warfare.  Gas warfare was not used in WWII so these did not see widespread use although the surplus market was full of them up to about 1960 in the USA.
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Geoff Fors
Monterey, California
PA0NVD
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Nico and Chappie (Chappie is the dog...)


« Reply #3 on: April 22, 2018, 09:01:08 AM »

Didn't know that, thanks for the info. Very sensitive receiver, I hear here in CR USA hams at the whip.
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AJ1G
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« Reply #4 on: April 22, 2018, 06:52:29 PM »

Although not used for gas attack warning, I have read that they were often used for a similar function, air attack warnings.  The GRR-5 was also used for that purpose.
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Chris, AJ1G
Stonington, CT
af6im
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AF6IM jumping from a C54G, 1999 Quincy Illinois.


« Reply #5 on: May 02, 2018, 03:19:14 PM »

Never knew about this interesting little rcvr. Amazing that it fired right up after being dormant for decades. Thanks for posting about it.

AF6IM
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