BC221 Calibration..How it was done.....

[pwdrive]

If you ever wondered how the BC221 Frequency Meters calibration book was done then see the attached PDF, an interesting article from Electronics Magazine May1944 by Joseph Tellier including a 126 valve "computer"....

Lawrence.

[Rascal]

A very interesting article. Thanks for posting.

I have a couple of BC221 and some scrap spare units (front & chassis). I also have the TS174, which as you are no doubt aware is the 20mhz-250mhz version of the BC221 (virtually physically identical to each other,). I was fortunate to come across the TS174 complete with the original internal (removable) 240 volt power supply intact and working – this comes in handy as a ready power supply for the BC221's.

Paul

[pwdrive]

No problem Paul, I'm glad you found it interesting.

I do not have an original power supply for mine, I did fire it up using a temporary supply some time ago and it all seemed to work, I should really build a dedicated PSU for it really as it is a handy piece of gear.

The Plexiglass frequency booklet cover is cracked on mine, if I can pick up a rough BC221 but with a decent lid I might go for it as I am also after a decent reduction drive and tuning capacitor for a Regenerodyne receiver project I am hoping to return to this winter.

Lawrence.

[Rascal]

Hi Lawrence

I am sure the scrap/spare units I have don't include the booklet/cover, if they do I will let you know. Unfortunately the spare reduction drives I have are 'notchy', probably badly worn (cant face chucking out), but I will double check.

I have never come across a BC221 with a mains supply, I guess that being used 'out in the field' meant that battery option was the more common supply. I may have just fallen lucky with the TS174.

I have a pdf of the 'War Department Technical Manual 1944' for the BC221 which just about covers every build version, operation, maintenance, etc . If you don't already have it I can post it here.

Paul

[Skywave]

If you ever wondered how the BC221 Frequency Meters calibration book was done then see the attached PDF, an interesting article from Electronics Magazine May1944 by Joseph Tellier including a 126 valve "computer"....

Lawrence.

Hmm - I have a problem with that download. Adobe states that I need the latest version of their Reader. When I attempted to install the latest version, I got the message that the version installed here is the latest: v.9.4.0.
I'd really like to read that pdf, but cannot. Can anyone advise or help with this, please?

Al. / Aug.6, 2013 //

[Refugee]

The PDF file is showing that it is locked with a password. I have had a look and have not been able to get the cracker working on my system.

[pwdrive]

If you ever wondered how the BC221 Frequency Meters calibration book was done then see the attached PDF, an interesting article from Electronics Magazine May1944 by Joseph Tellier including a 126 valve "computer"....

Lawrence.

Hmm - I have a problem with that download. Adobe states that I need the latest version of their Reader. When I attempted to install the latest version, I got the message that the version installed here is the latest: v.9.4.0.
I'd really like to read that pdf, but cannot. Can anyone advise or help with this, please?

Al. / Aug.6, 2013 //

I had a similar problem Al, I downloaded the latest free version, that was a bit of an effort as I am not computer speak, and I found that the download instructions didn't initially say what it said on the can as it were, anyways the latest version was downloaded and it read the article ok, the article was then saved in a file on my PC, it is that file which I uploaded to the forum, if you don't have any luck PM me and I will send you the file as an Email attatchment and you can fiddle around with it at will.

Failing that, someone on the forum might know how to convert it to something more managable/readable.

It's definately worth a read.

Lawrence.

[camallison]

Try right clicking on the pdf link and save it to somewhere you can find it again. Then open it with your Adobe Reader from that downloaded file. I am having the same problem with all my pdf reader programmes on direct opening too.

Colin

[pwdrive]

Ah...I think there's a definate problem, I just clicked on the link I initially posted and all I get is a blank (grey) PDF screen and at the top it said "this PDF might not be displayed properly" I fiddled around but zilch.

However if I open the file I saved it to on my PC it opens and reads ok....So dunno what's to do now?....Anyone.

I hope it's not copywrite or anything serious, I down loaded it from the royal signals site, I didn't have to join or anything, it downloaded of its own free will so I assumed it was ok to do so.

Lawrence.

[pwdrive]

I'm not to happy with this....I hate posting duffers, I like to keep things proper as a defacto reference and for it to do what it says on the tin as it were.

Sorry about this guys/gals....I reckon someone can crack the problem maybe.

Lawrence.