{"id":5661,"date":"2014-11-16T15:17:58","date_gmt":"2014-11-16T23:17:58","guid":{"rendered":"http:\/\/mightyohm.com\/blog\/?p=5661"},"modified":"2015-09-26T11:10:56","modified_gmt":"2015-09-26T18:10:56","slug":"a-spotters-guide-to-the-sbm-20-geiger-counter-tube","status":"publish","type":"post","link":"https:\/\/mightyohm.com\/blog\/2014\/11\/a-spotters-guide-to-the-sbm-20-geiger-counter-tube\/","title":{"rendered":"A spotter’s guide to the SBM-20 Geiger counter tube"},"content":{"rendered":"
\"SBM-20<\/a>
click to enlarge<\/figcaption><\/figure>\n

The picture above shows a variety of Geiger tubes that are commonly sold under the name “SBM-20”. This post is an attempt to clear up some of the confusion around these tubes and to share\u00a0some information about the different tube styles I have encountered in the wild since I first started selling Geiger Counter kits<\/a> in 2011.<\/p>\n

This is my spotter’s guide to the SBM-20 Geiger counter tube.<\/p>\n

SBM-20<\/h4>\n

This is the quintessential Soviet Geiger Counter tube. 400V operating voltage. 105mm overall length. Gold (brass?) color. Symmetric end caps. Positive terminal is\u00a0usually\u00a0marked ‘+’, but if not, it’s the end closest to the CBM-20 marking. Date codes are always four digit, but\u00a0I have seen both MMYY and YYMM (assuming I am interpreting the numbers correctly).\u00a0Year of manufacture varies widely but most are 1970s – 1990s.<\/p>\n

SBM-20U<\/h4>\n

Very common alternate version of the SBM-20. Shorter 95mm overall length. Positive terminal is exposed rod with no end cap. Soldering to this terminal can be a challenge as the plating is usually quite oxidized and the underlying metal is steel. \u00a0I’ve also seen the internal glass seals fail after soldering. These are often sold as SBM-20 tubes, and unscrupulous eBay sellers will sell the SBM-20\/SBM-20U interchangeably.<\/p>\n

SBM-20 (alternative negative terminal style)<\/h4>\n

Slightly longer positive terminal. 105mm overall length. Negative terminal is formed from the tube body (cost saving design?). Tubes I have seen are marked ’77’, presumably date code for 1977.\u00a0Rare.<\/p>\n

STS-5 \/ CTC-5<\/h4>\n

Older version of the SBM-20. Slightly longer overall length, approx. 110mm. Silver color. Positive terminal is marked + and closest to the CTC-5 marking. Date codes I have seen are mid-1960s through 1970s. I haven’t confirmed this, but I suspect date code is roman numeral month followed by arabic numeral year, eg. VIII 65. Aside from longer overall length, properties and performance are very similar to SBM-20. Less common than SBM-20, presumably because they are older and were not manufactured in great numbers across as many years. Sometimes sold under the name SBM-20. \u00a0They are generally interchangeable with “real” SBM-20 tubes, but given that they are significantly older, failure rate might be higher (unconfirmed).<\/p>\n

Summary<\/h4>\n

My Geiger Counter kit<\/a> will accommodate the STS-5 and all of the SBM-20 variants shown. The SBM-20U requires a short jumper wire to connect the positive terminal to the PCB.\u00a0I recommend using an alligator clip or wrapping a wire around the terminal to avoid compromising the glass to metal seal with the heat of the solder.<\/p>\n","protected":false},"excerpt":{"rendered":"

The picture above shows a variety of Geiger tubes that are commonly sold under the name “SBM-20”. This post is an attempt to clear up some of the confusion around these tubes and to share\u00a0some information about the different tube styles I have encountered in the wild since I first started selling Geiger Counter kits … Continue reading A spotter’s guide to the SBM-20 Geiger counter tube<\/span> →<\/span><\/a><\/p>\n","protected":false},"author":2,"featured_media":5666,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2},"jetpack_post_was_ever_published":false},"categories":[65],"tags":[401,479,480,481],"class_list":["post-5661","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-kits","tag-geiger","tag-sbm-20","tag-sts-5","tag-tubes"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"https:\/\/mightyohm.com\/blog\/wp-content\/uploads\/2014\/11\/sbm_20_sts_5_2_resized.jpg","jetpack_shortlink":"https:\/\/wp.me\/pioCd-1tj","jetpack_sharing_enabled":true,"jetpack_likes_enabled":true,"jetpack-related-posts":[{"id":14668,"url":"https:\/\/mightyohm.com\/blog\/2020\/12\/mightyohm-kits-are-now-available-from-amazon-com\/","url_meta":{"origin":5661,"position":0},"title":"MightyOhm Kits are now available from Amazon.com","author":"Jeff","date":"December 3, 2020","format":false,"excerpt":"Exciting news! My hobby electronics kits are now available from my Amazon store with free expedited shipping for Prime members. Direct links below: MightyOhm Geiger Counter Kit Bundle - This version of the kit includes a sensitive SBM-20 Geiger tube, laser-cut case, and 2xAAA batteries. If you already own a\u2026","rel":"","context":"In "Announcements"","block_context":{"text":"Announcements","link":"https:\/\/mightyohm.com\/blog\/category\/announcements\/"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/mightyohm.com\/blog\/wp-content\/uploads\/2020\/12\/Amazon-logo-500x210.png?resize=350%2C200&ssl=1","width":350,"height":200},"classes":[]},{"id":15745,"url":"https:\/\/mightyohm.com\/blog\/2022\/11\/super-cyber-sale-geiger-counter-kits-are-20-off-amazon\/","url_meta":{"origin":5661,"position":1},"title":"Super Cyber Sale – Geiger Counter Kits are 20% off @ Amazon","author":"Jeff","date":"November 25, 2022","format":false,"excerpt":"Geiger Counter Kits are now on sale at Amazon. PS. SBM-20 Geiger Counter Tubes and Rescue Shields are on sale too. Sale ends 12\/1.","rel":"","context":"In "Announcements"","block_context":{"text":"Announcements","link":"https:\/\/mightyohm.com\/blog\/category\/announcements\/"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/mightyohm.com\/blog\/wp-content\/uploads\/2011\/12\/geiger_with_case.jpg?resize=350%2C200&ssl=1","width":350,"height":200},"classes":[]},{"id":4298,"url":"https:\/\/mightyohm.com\/blog\/2011\/10\/new-product-laser-cut-case-for-the-geiger-counter-kit\/","url_meta":{"origin":5661,"position":2},"title":"New product: Laser-cut Case for the Geiger Counter Kit","author":"Jeff","date":"October 24, 2011","format":false,"excerpt":"I'm happy to announce the release of a custom laser-cut case for the Geiger Counter kit! The case, which is made of high quality clear acrylic, comes with standoffs and all the hardware needed to assemble it. The case includes access holes for the HV adjustment, the piezo beeper, and\u2026","rel":"","context":"In "Announcements"","block_context":{"text":"Announcements","link":"https:\/\/mightyohm.com\/blog\/category\/announcements\/"},"img":{"alt_text":"Geiger Counter with Lasercut Case","src":"https:\/\/i0.wp.com\/mightyohm.com\/files\/flickr\/6275026497_3cf9f175b2.jpg?resize=350%2C200","width":350,"height":200},"classes":[]},{"id":15960,"url":"https:\/\/mightyohm.com\/blog\/2023\/11\/mightyohm-geiger-counter-kits-on-sale-at-elektor-com\/","url_meta":{"origin":5661,"position":3},"title":"MightyOhm Geiger Counter Kits on sale at elektor.com","author":"admin","date":"November 7, 2023","format":false,"excerpt":"Elektor is currently offering a promotion on MightyOhm Geiger Counter Kits. These are the same kits that I have sold at very popular workshops at ToorCamp and Chaos Camp. 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Happy Halloween!","rel":"","context":"In "Announcements"","block_context":{"text":"Announcements","link":"https:\/\/mightyohm.com\/blog\/category\/announcements\/"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/mightyohm.com\/blog\/wp-content\/uploads\/2012\/02\/6167948098_581ddf3d7d.jpg?resize=350%2C200&ssl=1","width":350,"height":200},"classes":[]},{"id":13508,"url":"https:\/\/mightyohm.com\/blog\/2020\/04\/alpha-radiation-makes-sparks-detects-smoke-and-eliminates-static-cling\/","url_meta":{"origin":5661,"position":5},"title":"Alpha radiation makes sparks, detects smoke, and eliminates static cling","author":"admin","date":"April 6, 2020","format":false,"excerpt":"https:\/\/youtu.be\/ZBHIp967TD8 Applied Science posted a video this week showing how a strong alpha source can be used to detect smoke or eliminate static cling. My Geiger Counter kit makes a cameo in the video. Note that the SBM-20 Geiger-M\u00fcller tube that normally ships with the kit isn't sensitive to alpha\u2026","rel":"","context":"In "Kits"","block_context":{"text":"Kits","link":"https:\/\/mightyohm.com\/blog\/category\/kits\/"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/img.youtube.com\/vi\/ZBHIp967TD8\/0.jpg?resize=350%2C200","width":350,"height":200},"classes":[]}],"_links":{"self":[{"href":"https:\/\/mightyohm.com\/blog\/wp-json\/wp\/v2\/posts\/5661","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/mightyohm.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/mightyohm.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/mightyohm.com\/blog\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/mightyohm.com\/blog\/wp-json\/wp\/v2\/comments?post=5661"}],"version-history":[{"count":18,"href":"https:\/\/mightyohm.com\/blog\/wp-json\/wp\/v2\/posts\/5661\/revisions"}],"predecessor-version":[{"id":5679,"href":"https:\/\/mightyohm.com\/blog\/wp-json\/wp\/v2\/posts\/5661\/revisions\/5679"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/mightyohm.com\/blog\/wp-json\/wp\/v2\/media\/5666"}],"wp:attachment":[{"href":"https:\/\/mightyohm.com\/blog\/wp-json\/wp\/v2\/media?parent=5661"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/mightyohm.com\/blog\/wp-json\/wp\/v2\/categories?post=5661"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/mightyohm.com\/blog\/wp-json\/wp\/v2\/tags?post=5661"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}