BC 611 Frequency change

Radio Telephone and Telegraph Transmitting and Receiving Equipment
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packer
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BC 611 Frequency change

Post by packer » Mon Nov 13, 2017 6:53 am

Hi all I have 3 bc 611 radio and I want to try and get them the same frequency, I do have a box of crystals and coils , How difficult is it to change over
the parts will it work or have to retune ,,,all the best colin

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wa5cab
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Re: BC 611 Frequency change

Post by wa5cab » Mon Nov 13, 2017 4:52 pm

It isn't difficult but you will have to re-tune both the receiver and the transmitter. If the radios all work OK on their current channels, you will not need to touch the I.F. transformers. But you will need a test case in order to successfully do it. If you tune them out of the case (assuming that you can somehow power them up), they will be severely de-tuned when you put them back into the case. So you need a test case with holes drilled and slots milled in it to let you put a tuning tool through. And also to hold the batteries or inverter. I have a complete IE-17-E and do that work for $50 to $65 per working radio (depending upon model). But shipping three of them twice across the pond would double or triple that. So too costly.

All of the original test cases were made from unpainted radio cases but they were made to use with either the IE-17-E Test Set with I-135-E, F or G test unit or with an IE-15 ad hoc external setup that included the special connector that attaches to the bottom of the radio. So they all, besides the slots and holes, had the microphone and earphone wells, the two bottom cover hinges and the one bottom cover latch hinge cut off.

After WW-II, the Signal Corps came out with IE-37, the main component of which was a test case that had the holes and slots and no microphone or earphone well but did have the bottom cover and latch hinges. They used a special thick bottom cover and headset for access to the receive audio. You used another working radio as a signal generator or as a detector, for tuning the receiver and the transmitter in the test case. If you modify a regular radio case without cutting anything off, you can do the same thing using the earphone out of one of the radios plus the top and bottom covers. You connect a capacitor so as to make the 3S4 modulator also oscillate, so you do not need the microphone. If you can locate a damaged radio case, I can give you the milling and drilling instructions. Or I can make and sell you one for about $100 plus shipping. The IE-37 also came with an attenuator that screwed on in place of the antenna cap. This was to reduce the signal strength of the test transmitter or the sensitivity of the test receiver. That's the only part of the IE-37 that I have never had and don't know exactly how it was made. But I believe that one could be made from an antenna cap.
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packer
Sergeant Major of the Gee
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Posts: 296
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Re: BC 611 Frequency change

Post by packer » Tue Nov 14, 2017 11:38 am

Hi wa5cab thank you for the help all the best colin

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