Radiocontest July 2007

Rob Lenski

6C8G Dual Triode Regen

This set started out as the very simple set featured in the 1934 Official Short Wave Radio Manual: Complete Experimenter's Set-Building and Servicing Guide, reprinted by Lindsay Publications Inc. It uses a single 6C8G twin triode tube. I've modified it by adding a resistor just ahead of the interstage transformer allowing me to run 90VDC to the set and still limit the detector voltage to under 30VDC.

I also bumped up the interstage transformer from 1:3 to 1:5, and increased the capacitance of the throttle capacitor from the specified 100pf to 340 pf. It's still a simple regenerative set quite similar to what a homebrewer would have built in the 1940's.

This is my fourth homebrew regen, and my favorite. It pulls in quite a few shortwave stations, tunes easily, has more than enough volume on most stations, and is generally just a pleasant set to operate. The 6C8G tube is probably one of the cheapest that you'll find, yet it has a lot of amplification. The only downside is the grid cap set-up, but I think that feature enhances the 1940's look. I'd recommend this set to anyone looking for a simple, but effective regenerative set.

Pictures

Logs

     # Date Time UTC Frequency ID 
1 7/31/2007 15:09 9330 khz WBCQ, Maine USA 
2 7/31/2007 15:11 9370 WTKC NC, USA 
3 7/31/2007 15:21 9515 Radio Canada Int'l 
4 7/31/2007 15:30 9625 CBC Canada 
5 7/31/2007 15:43 9955 WEWN AL, USA 
6 7/31/2007 15:45 9985 WWCR TN, USA 
7 7/31/2007 16:17 9450 WEWN AL, USA 
8 7/31/2007 16:26 9385 WWRB TN, USA 
9 7/31/2007 16:45 9265 WMLK PA, USA 
10 7/31/2007 16:54 9565 WRMI 
11 7/31/2007 17:05 9480 KAIJ TX, USA 
12 7/31/2007 17:50 11775 Anguilla Unvsty Ntwrk 
14 7/31/2007 17:54 11930 WRMI 
14 7/31/2007 18:13 9840 WHRI SC, USA 
15 7/31/2007 20:09 10955 Deutsche Welle Germany 
16 7/31/2007 20:21 11865 Deutsche Welle Germany 
17 7/31/2007 20:30 11760 Radio Havana Cuba 
18 7/31/2007 22:13 9820 Venezuela Radio Nacional 
19 7/31/2007 22:20 9925 Radio Havana Cuba 
20 7/31/2007 0:22 9420 Voice of Greece 
21 7/31/2007 0:38 9665 Radio Nacional Do Brasil 
22 7/31/2007 0:40 9715 Voice of America 
23 7/31/2007 0:42 9845 Netherlands Radio 
24 7/31/2007 0:45 9570 China Radio Int'l 
25 7/31/2007 0:48 9665 Voice of Russia 
26 7/31/2007 0:52 5890 Radio Thailand 
27 7/31/2007 0:58 6145 NHK World Japan 
28 7/31/2007 1:00 9925 Croatian Radio Croatia 
29 7/31/2007 1:07 11935 Radio Japan/NHK World 
30 7/31/2007 1:10 9790 China Radio Int'l 
31 7/31/2007 1:22 6000 Radio Havana Cuba 
32 7/31/2007 1:33 5810 WEWN AL, USA 
33 7/31/2007 1:35 5070 WWCR TN, USA 
34 7/31/2007 1:51 6175 Voice of Vietnam 
35 7/31/2007 1:53 6010 Radio Sweden 
36 7/31/2007 1:58 5100 Radio Sweden 
37 7/31/2007 2:06 9680 Radio Taiwan Int'l 
38 7/31/2007 2:08 10000 WWV 
39 7/31/2007 2:11 11835 Family Radio Worldwide 
40 7/31/2007 2:14 13730 Radio NZ Int'l 
41 8/1/2007 4:32 9515 Voice of Russia World Service 
42 8/1/2007 4:34 9860 Voice of Russia World Service 
43 8/1/2007 8:34 5000 WWV CO, USA 
44 8/1/2007 18:13 13690 Family Radio Worldwide FL USA 
45 8/1/2007 18:18 9975 WWCR TN, USA 
46 8/1/2007 18:21 12160 WWCR TN, USA 
47 8/1/2007 19:18 13820 WRMI NC, USA 
48 8/1/2007 19:22 13845 WWCR TN, USA 
49 8/1/2007 20:17 11695 Voice of the Islamic Republic, Iran 
50 8/1/2007 20:36 13670 WHRI SC, USA 
51 8/1/2007 20:40 9515 Radio Romania Int'l 
52 8/1/2007 21:06 11675 BBC World Service UK 
53 8/1/2007 21:13 15205 Deutsche Welle Germany 
54 8/1/2007 21:22 9700 Radio Bulgaria 
56 8/1/2007 21:31 11600 Radio Prague Czech  
57 8/1/2007 21:33 9990 Radio Cairo, Egypt 
58 8/1/2007 23:07 11840 CRI, China 
59 8/1/2007 23:09 11700 Radio Bulgaria 
60 8/1/2007 23:51 13680 Radio Nacional Venezuela 
61 8/1/2007 00:35 (8:35 EST) 9875 Radio Vilnius Lithuania 
62 8/1/2007 0:56 9515 WHRI SC, USA 
63 8/1/2007 1:09 11780 NHK World Japan 
64 8/1/2007 1:15 9600 Voice of America USA 
65 8/1/2007 1:18 11705 Voice of America USA 
66 8/1//2007 1:24 6180 Radio Havana Cuba 
67 8/2/2007 9:10 9580 Australia Radio  
68 8/2/2007 9:35 5850 WEWN AL, USA 
69 8/2/2007 20:09 15590 KTBN UT USA 
70 8/2/2007 20:16 15695 IBRA Radio 
71 8/2/2007 20:21 15600 Deutsche Welle Germany 
72 8/2/2007 23:53 15745 WEWN AL, USA 
73 8/2/2007 23:57 15335 Radio Nacional Venezuela 
74 8/2/2007 :34 (8:34 EST) 9460 Radio Cairo, Egypt 
75 8/2/2007 0:41 13725 Radio Canada Int'l 
76 8/3/2007 10:14 6120 NHK World Japan 
77 8/3/2007 19:30 15825 WWCR TN, USA 
78 8/3/2007 1:26 5755 KAIJ TX, USA 
79 8/3/2007 1:40 5745 WWRB TN, USA 
80 8/3/2007 2:06 9550 CRI, China 
81 8/3/2007 2:20 9560 KBS World Radio S. Korea 
82 8/3/2007 2:23 9745 HCJB VO The Andes Quito Ecuador 
83 8/3/2007 2:32 9370 WTJC NC, USA 
84 8/3/2007 2:35 9780 Deutsche Welle Germany 
85 8/3/2007 3:02 9505 Family Radio Worldwide, FL USA 
86 8/3/2007 12:09 11760 CRI, China 
87 8/3/2007 12:18 9650 KBS World Radio S. Korea 
88 8/3/2007 12:21 9660 BBC World Service UK 
89 8/3/2007 12:26 9495 WHRI SC, USA 
90 8/3/2007 12:37 15240 Radio Sweden 
91 8/3/2007 1:13 13680 Radio Habanna Cuba 
92 8/3/2007 19:31 15315 Netherlands Radio 
93 8/3/2007 21:26 11645 BBC World Service UK 
94 8/3/2007 21:32 15600 Radio Taiwan Int'l 
95 8/3/2007 21:45 15400 BBC World Service UK