Radio Receiver BC-454-B
 

My friend brought this around. Can anyone tell me anything about it? What is missing?
John.

Re: Radio Receiver BC-545-B
 

The Dynamotor is missing.

It sits on those 3 pins and provides the HT.

Cheers

Mike T

Re: Radio Receiver BC-545-B
 

Think this cover the 80M band, they all vary and some 455Kc were used as a tuneable IF.

Re: Radio Receiver BC-545-B
 

One of the series of Command sets used in WW2 US aircraft. Much info on the Internet.

Re: Radio Receiver BC-545-B
 

Thanks Mike, so that is what the 4 rubber vibration mounting posts are for. I took the lid off part of it and inside are the valves and inside the lid it says Dynamotor. So is that part of the power supply?

John.

Re: Radio Receiver BC-545-B
 

The dynamotor provides the HT supply (around 250volts) input from the 28 volt aircraft supply. The heaters of the valves are connected to be run from the aircraft supply.

Re: Radio Receiver BC-454-B
 

Normally 12V valves inside.

Re: Radio Receiver BC-454-B
 

This article is a good introduction:
http://www.g4kfk.co.uk/5702_RSGB_Command_Receivers.pdf
. . . and similar here:
http://www.ad5x.com/images/Articles/ARC5convert.pdf
Manuals are on the usual Boat Anchor site.
Peter G3PIJ

Re: Radio Receiver BC-454-B
 

Check the wiring of the heaters. Many have been converted from the usual 24 V heater supply to 12 V.
The dynamotor uses the same supply to make the HT ( about 225 V DC ).

Those radios can be wonders of sensitivity but the whine/noise of the dynamotor can spoil the joy. Dynamotors need maintenance before using them.

Although i personally run those era radios on dynamotors many use mains power supplies.

The capacitors in the metal cans need checking, many are bad after all the years. Cans can be unsoldered or opened with a rotary tool with cutting disk.
Change the content and solder the cut-off part with a large iron, the cans are usually made from copper.

Audio output impedance is for higher value headphones. Make sure you use the right type for best performance.

Re: Radio Receiver BC-454-B
 

Thank you everyone for your replies, Set belongs to my friend, he is into clocks. I suspect He may be selling it. Nice to know it could be a very sensitive set. Looks like it has been used on an external power supply, as someone has pencilled in all the contacts.

John.

Re: Radio Receiver BC-454-B
 

Hi John,

One plus point on your friend's receiver is that the plug-in module below the tuning dial hasn't been drilled out to take a volume control and a BFO on/off switch. That was a common mod and also usually resulted in some butchery inside the set.

The original power connector on the rear of the chassis is still present too, often these were hacked out and an octal socket fitted.

These sets don't fetch big prices usually but with the set in question being largely un-modded it might attract more interest.

Cheers

Roger

Re: Radio Receiver BC-454-B
 

It is part of the ARC 5 series of aircraft radios.
Filaments are wired in series parallel in some models as they used a 24 (28) v dynamotor.

They are asking some insane prices at the U.S. ham fairs for these , based on the last two I went to. Anywhere from $15-$ 95 USD!

If they are restorable, the military aircraft restorers are always looking for them here.
The mounting racks are the hard to find item, especially the multiple radio ones. (I actually had a call from the group that was restoring the WW2 bomber at the Boeing Airplane Museum in Seattle WA. U.S.A. looking for working ones for the aircraft. Sadly, the bomber crash landed in water shortly after take off. Not sure if they re-restored it or not).

Re: Radio Receiver BC-454-B
 

Hi Frank,

The prices you quote are about the same here in the UK, I'd expect to pay about 25 UKP for a modified receiver and maybe 40 UKP for a transmitter. As you say, the accessories are the pricey items, especially a decent modulator. The rarest receiver is the one that covers the Medium Wave as they needed only the dynamotor and heater wiring changed to serve as a 12V car radio.

The ARC-5 was primarily used by the US Navy but the SCR-274N series was used by the USAAF. There's a useful book, published many years ago, that covers a lot of the mods done to these radios and which will be useful for someone "back-engineering" a receiver or transmitter back to the original spec. See:-

http://www.w7ekb.com/glowbugs/Milita...mmand_sets.PDF

I have small collection here with enough hardware to make a single TX and RX installation on two trays and with the original connectors - but I have given up looking for a modulator!

73

Roger

Re: Radio Receiver BC-454-B
 

The modulators are a hen's tooth item here also.
BTW- The plug on the back of the chassis allowed the radio to be connected to a multiple radio rack system. IIRC I have one that holds 3 or 4 radios.

There are an almost endless series of articles on the ARC 5 series of radios in the following magazines: QST, CQ, Ham Radio, and Electric Radio. Plus the afore mentioned Command Sets compendium, and The Surplus Radio Manual- Vol 1-4 IIRC. It's quite hard to obtain the original ones now. They do turn up at ham fairs here from time to time.

There is a 'Readers Guide to Periodical Literature" that is supposed to be an index to articles written in magazines. You might even try there to find the magazines & issues that have the articles on the ARC 5 series.

Oh, and some of them used a 175KC IF freq. also I have one of those IF strips in my parts box. The little "Meat paste pot" cap. cans are starting to fail (Wartime quality) as are the "bath tub" style capacitors.