{"id":7659,"date":"2010-03-13T20:23:00","date_gmt":"2010-03-13T09:23:00","guid":{"rendered":"https:\/\/www.homebrewradio.us\/blog\/2010\/03\/13\/hamfest-tips-12-volt-tubes-and-cigar-box-radios\/"},"modified":"2025-07-21T23:16:57","modified_gmt":"2025-07-21T13:16:57","slug":"hamfest-tips-12-volt-tubes-and-cigar-box-radios","status":"publish","type":"post","link":"https:\/\/www.homebrewradio.us\/blog\/2010\/03\/13\/hamfest-tips-12-volt-tubes-and-cigar-box-radios\/","title":{"rendered":"Hamfest tips, 12 Volt Tubes and Cigar Box Radios"},"content":{"rendered":"

\"\"<\/a>Bill,<\/span><\/p>\n

\n
Enjoyed very much listening to your adventures in the UK – I very much want to visit Faraday’s lab!<\/span><\/p>\n

When going to the next radio rally\/hamfest, can I respectfully suggest the following:<\/span><\/p>\n

A jacket or waistcoat with lots of pockets, the bigger the better. A backpack with some more bags inside. An idea also would be some kind of lock or restraint so that you could lock a full bag to a post or something out of the way in case you buy something heavy – I usually ask a stall-holder to look after a bag which they are often willing to do after I have made a reasonable purchase from them!<\/span><\/p>\n

In one of the pockets put a small multimeter with a working ohms range – to test transformers, coils, valve heaters, etc. before purchase.<\/span><\/p>\n

In another pocket put valve\/transistor (or whatever you are interested in) data books or have a handheld thingy (<\/span>iPhone<\/span>, etc.) with a working Internet connection where you can look up such things.<\/span><\/p>\n

In another pocket put a calculator (not needed if you have a handheld thingy) and a small notepad and pen\/cil to make notes and work things out and compare prices from competing stalls.<\/span><\/p>\n

A camera to take pictures of beautiful things you have no money for or intention of buying.<\/span><\/p>\n

Some personal news:<\/span><\/p>\n

Currently building a one-valve BC <\/span>FM receiver<\/span> – lots of fun. Recently built a MW 2-car-valve superhet which I listen to the <\/span>World Service<\/span> on here in <\/span>Brussels<\/span>. I build them into Cuban cigar boxes my missus gets free from tobacco shops around the city and in airports.<\/span><\/p>\n

The fridge broke down and I discovered it was the thermostat and so I decided – foolishly – to spare the money for the replacement part (unemployed) and build one from components I already had in the radio room. Big mistake. I have been fiddling with different resistor values, broken Veroboard tracks and recalcitrant 740 op-amps for weeks now. Managed to freeze an entire bag of perfectly good carrots! I think I am on the tail-end of the prototype development process now and the production model should emerge in a week or so. The missus was initially impressed but now, sadly, not so. C’est la vie.<\/span><\/p>\n

I experimented with QRSS using a simple PIC-controlled single car-valve crystal-regulated transmitter and a crystal immersed in a large jar of water for temperature stability. I managed to get seen by various grabbers and so am moderately happy. WSPR might be on the boards next, if I can do it with a PIC and a valve…<\/span><\/p>\n

Good luck with the RC aeroplanes – try and keep the propellor pointed away!<\/span><\/p>\n

73 cheers<\/span>
Nick on4Nic \/ m0NjP<\/span><\/p>\n

PS Car-valves are designed to operate from 12V only – heater and HT. Great fun for fiddling around with and completely safe – so long as you don’t break them or burn yourself on the glass!<\/span><\/p>\n

<\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"

Bill, Enjoyed very much listening to your adventures in the UK – I very much want to visit Faraday’s lab! When going to the next radio rally\/hamfest, can I respectfully suggest the following: A jacket or waistcoat with lots of pockets, the bigger the better. A backpack with some more bags inside. An idea also … Continue reading “Hamfest tips, 12 Volt Tubes and Cigar Box Radios”<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":7660,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[133,101],"tags":[],"class_list":["post-7659","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-hamfests-and-flea-markets","category-tubes"],"_links":{"self":[{"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/posts\/7659","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/comments?post=7659"}],"version-history":[{"count":1,"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/posts\/7659\/revisions"}],"predecessor-version":[{"id":7661,"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/posts\/7659\/revisions\/7661"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/media\/7660"}],"wp:attachment":[{"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/media?parent=7659"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/categories?post=7659"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/tags?post=7659"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}