Rob Lenski
2009 Shortwave

Description

This year I entered a dual acorn (955 triode) set for use on shortwave. The set is pretty much a copy of the 6C8G set in the 1934 shortwave tuning manual, except rather than use a single twin triode, I used two tubes. I also ran 150 volts to the tube handling the amplifying duties, but knocked the detector tube's plate voltage down to ~28 volts.

You may notice in the photo that the tuning coil and detector tube are on a raised bracket so as to keep them close to the tuning and throttle caps. This allows for shorter wiring which seemed to help reduce some of the problems that I initially had running this circuit. It may also have helped that the 955 triode has a lower amplification factor than the 6C8G, which it seems to me makes for an easier to use set. Having said that though, the set still had plenty of volume.

If you look at the lower right corner of the photo, you'll notice a bit of magnet wire. For the antenna connection I simply used a gimmick capacitor, which is simply two short lengths of insulated wire twisted together, but not connected electrically. It makes an itty-bitty capacitor. I found that this set does not like too tight of an antenna connection. If it's too tight, the throttle capacitor won't have sufficient capacitance and the set won't regenerate.

All in all, this circuit is easy to build, was a joy to operate, and really pulls in the signals. Much of Europe, and Asia can be heard. If you use acorn tubes you can build a fairly small set, and unlike many other tubes, the filaments in the 955's glow quite brightly.



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Log

Date	#	Time	Station	Frequency
	
8/1/2009	
   1	8:20	Radio Australia	9580	
   2	19:07	Radio Bulgaria	9700	
   3	19:11	Voice of Greece	9420	
   4	19:17	Voice of Russia	9890	
   5	19:28	Voice of Russia	9665	
   6	19:40	WWV	10000	
   7	20:10	WINB Red Lion PA	9265	
   8	20:12	Albanai, Radio Tirana	9345	
   9	20:13	WTJC Newport, NC	9370	
   10	20:15	Radio Prague	9440	
   11	20:18	WYFR Family Radio Worldwide	9505	
   12	20:22	China Radio Int'l	9570	
   13	20:23	Bucharest Radio Romania Int'l	9580	
   14	20:28	Int'l Radio of Serbia	9675	
   15	20:50	Zambia CVC Int'l	4965	
   16	20:59	Radio Canada Int'l	5190	
   17	21:00	Voice of Vietnam	5265	
   18	21:04	Radio Prague	5290	
   19	20:35	Radio Sweden	6010	
8/2/2009	
   20	18:04	Equatorial Guinea & Radio Africa	15190	
   21	18:09	Radio Romania Int'l	9790	
   22	18:15	WWRB	9385	
   23	18:16	USA VOA	9415	
   24	18:23	WTJC Newport, NC	9370	
   25	18:25	Moldavia	9665	
   26	18:35	Voice of Turkey	9830	
   27	18:42	WYFR Family Radio Worldwide	10830	
   28	20:12	NHK World, Radio Japan	6145	
   29	20:14	Anguilla, Worldwide Univ Network	6090	
   30	20:16	Spain Radio Exterior Espana	6055	
   31	20:20	China Radio Int'l	6020	
   32	20:35	WWCR	9980	
   33	20:36	WEWN	11520	
   34	20:42	Radio Canada Int'l	13725	
   35	20:44	Cuba, Radio Habanna Cuba	13760	
8/3/2009	
   36	19:25	WWCR	7465	
   37	19:30	Venezuela	15250	
   38	20:17	Radio Ukraine Int'l	7440	
   39	20:27	WWRB	3185	
   40	20:28	WWRB	3215	
   41	20:29	CHU (Time Canada)	3330	
8/4/2009	
   42	17:02	EWTN	15610	
   43	18:53	WWV	15000	
   44	19:17	China Radio Int'l	6145	
   45	19:20	China Radio Int'l	11841	
   46	20:09	Radio Thailand World Service	15275	
   47	20:15	Radio Canada Int'l	6100	
   48	20:20	WBCQ	5110	
   49	20:24	WINB Red Lion PA	9265	
   50	20:30	WWCR	5935	
   51	20:32	WYFR Family Radio Worldwide	5950	
   52	20:34	CHU (Time Canada)	7335	
   53	20:36	WYFR Family Radio Worldwide	15440	
   54	20:40	Radio Slovakia Int'l	5930	
   55	21:01	Radio Slovakia Int'l	9440	
8/5/2009	
   56	6:39	WWCR	5070	
   57	15:59	UK BBC World Service	12095	
   58	16:07	Albania, Radio Tirana	13640	
8/7/2009	
   59	21:25	Voice of Vietnam	6175	
   60	21:32	Radio Havana Cuba	6140	
   61	21:34	Radio Havana Cuba	6000	
   62	21:57	WYFR Family Radio Worldwide	15440	
   63	22:09	South Korea KBS World Radio	9580	
   64	22:10	Radio Taiwan Int'l	5950