Garry Nichols 2010 Entry

Stations Heard: 94

Well this year I decided to try 40 M CW for the HomeBrew Radio Contest. The circuit originally came from Owen Pool's web site: http://bellsouthpwp2.net/w/u/wuggy/fetgen.htm.

It worked surprisingly well on the BCB so I took it up to 80 M CW and then 40 M CW. I also made a few changes. I use only 1 turn on the tickler coil. I also moved the audio pickup point to the drain lead to make things louder. I did not notice any significant degradation in performance when I did this, but I am not expert at evaluating this.

That change required adding a .001 pF to ground from the drain. Without that I got nothing in the phones. I guess the RF needed to circulate to ground from the drain and was blocked by the high impedance of the phones.

Since the phones served also as source resistance in the original circuit, I added a pot in the source lead. The best operating point seemed to be at about 2k, Rs, which is what my old Brandes phones measure in DC resistance. Less Rs causes the gain to roll off rather rapidly and more causes it to roll off slowly, based on listening tests.

I tried an RFC between the .001 and phones, but it seemed to add no benefit so I removed it.

Body capacity effects are not too bad.

I added a screwdriver set bandset variable and a bandspread variable made up of a 10 pF ceramic in series with a 149 pF variable. Once I get things set to 40 M the bandset is left alone. The large jar lid stuck to a regular knob gives sufficient vernier action and is comfortable to the fingers.

The tickler coil is swung near the cold end of the tank coil by the wooden lever, which is pivoted on a screw counter sunk under the vertical wood post holding the tickler. It is not difficult to operate at all.

This circuit has never presented me with any unpleasant sounds on any of the three bands that I've tried it out on. So I decided to stay with the Brandes and not use a Bogen transformer and SPP and risk getting some sort of blast of sound because of this change. Sensitivity is pretty good with the Brandes.

I think that a stage of audio amplification and a bit of backoff on the gain of the MPF-102 might make this set an even better performer.

My antenna system for 40 M makes use of a two draw steel filing cabinet as ground, a 5 foot run to the window of my second floor room and then 24 feet sloping to an insulator and a brick on the lawn. (This is surprisingly good on the BCB, also!) It is resonant just above the 40 M band, according to my dip oscillator.

Antenna coil coupling used while listening is a bit closer than depicted in the photo. When I was down on the BCB I was experimenting with the antenna coil inside the tank coil, so that is why it is mounted on an arm. Notice the big brass nut stuck to the opposite side of the wood block? Keeps the assembly from tipping down with the weight of the antenna coil!

word of thanks to Scotch/3M for their "permanent" foam mounting squares, from which I seem to be lashing up everything lately. It is to me what Duct Tape is to Red Green!

						HomeBrew Radio Contest Summer 2010				
Garry Nichols 				
(All stations CW unless shown as SSB)				
				
Number	  Date	EDT	CALL	
1	1-Aug	PM       800	AA9MU	
2		802	KT8Z	
3		804	K4LO	
4		807	F3NB	
5		811	WD5CNC	
6		813	W4LK	
7		816	KA4KKE	
8		819	WC8W	
9		822	G6PZ	
10		823	WD4LZC	
11		832	WB0GKH	
12		858	YV5JF	
13		859	W4ED	
14		859	W1FBN	
15	2-Aug	AM       808	W9QB	
16		812	N0BUI	
17		812	NK4NFB	
18		815	W8UFM	
19		816	K2BSA	
20		821	K2OO	
21		PM       631	K4BK	
22		636	NN8R	
23		641	VE3MCA	
24		646	WA3ZKI	
25		652	K2FW	SSB
26		657	W3BI	
27		658	WB3AAI	
28		700	KE3NE	
29		836	K2QZ	
30		843	VE3VJC	
31		846	K1VTK	
32		849	5K1X	
33		856	UA6GR	
34		859	W8RDI	
35		902	OE3DIA	
36		903	K3FND	
37		907	KI4XH	
38		908	K2BIA	
39		910	W0CAB	
40	3-Aug	PM       932	W2MJN	
41		935	WA4YHA	
42		935	NG9D	
43		937	N9CK	
44		938	K5KV	
45		944	K1OM	
46		946	KD8JRB	
47		950	WB9JOX	
48		959	HK1N	
49		1050	W5HZU	
50	4-Aug	AM       838	KA4WQO/9	
51		838	K4TER	
52		841	W9ZN	
53		850	WA4BAM	
54		850	K8LJG	
55		PM       135	W2XU	
56		140	N2KW	
57		143	VE3PID	
58		151	K2ZF	
59		813	KK0I	
60		818	N2ATB	
61		822	N3RSD	
62		828	KB4GYT	
63		831	WB9DLC	
64		834	KC4KNN	
65		837	NC8J	
66		847	NO9T	
67		1009	N4HAF	
68		1018	K4CV	
69		1025	N4LZY	
70	6-Aug	PM      1011	K8BEG	
71		1013	N8JC	
72		1024	W5TZC	
73		1031	K5UA	SSB
74		1035	W4CAK	
75		1040	K8FN	
76		1128	YO4HG/MM	
77		1132	WB8NWA	
78	7-Aug	PM       935	WW3DE	
79		937	N4DW	
80		946	KF8R	
81		954	W4VR	SSB
82		958	KM5PS	
83		1050	W0MSM	
84		1050	VA3AH	
85		1052	W9IXV	
86		1055	N9RLO	
87		1058	W6UT	
88		1059	W9OLN	
89		1100	KA5VZG	
90		1107	AA6YX	
91		1110	K5MV	
92		1111	HA8RM	
93		1115	K9LJN	
94		1116	W6AEA