DIY TV Antennas 1. Single Bay Gray-Hoverman Antenna (SBGH) 2. Folded Dipole Antenna 3. Bow Tie Antenna 4. Television Frequency Table
1. Single Bay Gray-Hoverman Antenna (SBGH)
The Gray-Hoverman Antenna is an open source design that shows high performance for most Digital / HD channels broadcasting in the U.S. today. Details about the history and evolution of the design, as well as detailed technical information, can be found at the official web site: http://www.digitalhome.ca/ota/superantenna/ (Note: One visitor emailed me to say that they believe that this is more simply a Hoverman Antenna and NOT a Gray-Hoverman. In reviewing the original specification at digitalhome.ca, I still believe this is a Gray-Hoverman. But do want to acknowledge that this is a point of debate.)
As with my Folded Dipole Antenna, Antenna , my goal here is to provide guidelines for a version that is inexpensive, easy to assemble and simple to install in the attic. Still, this antenna should perform quite well for you. This is the antenna that I
currently use in my attic and I get 22 channels. Most of these are broadcasting from 45 or even 50+ miles away. (See the broadcast tower information for my area at TV Fool..) Fool
Parts List: •
2 - 4 foot 1x4 pine boards
•
6 - 3/4" Screws
•
6 - Finish Washers
•
10 - 2" Wood Screws
•
2 - 5' lengths of 14 gauge wire
•
1 - Balun - This transformer is needed to adapt the antenna's signal to your T.V.'s coax input. It is available from many sources. I got mine at my local Walmart for less than $5. See pictures below.
•
1 - 2 foot by 4 foot THIN plywood or masonite board
•
about 8 feet of 12" wide aluminum foil.
•
clear packing tape
Assembly:
Mark one of the 1x4 boards as shown. The first line should be 7" from the end of the board. The second should be 10" from the first. The third 10" from the second. s econd.
Mark one each of these three lines with two marks as show. The marks should be 5/8" in from the edges of the board.
For the actual antenna elements, I used 14 gauge wire that I got at my local home improvement store. It came in a 100' roll costing less than $7. For this project, I used two 5 foot lengths. Cut these lengths from the roll and try to straighten them out. They will probably still be a bit wavy at this point, but that is okay.
Now bend the wires to the shape described in the diagram. I marked my wires with a permanent marker at 5 1/2" and then every 7" to know where to bend.
Using a pair of pliers to hold the wire as you bend it will help you get sharper angles. When you are done with all of your bends, you will probably have about 7" extra wire to snip off. Trim this down to 5 1/2" AFTER you have made all of your bends. This leaves room to correct errors you might make during bending.
To attach the antenna elements to the board, I used some short screws and finish washers. I like the way these washers "grab" the antenna elements better than plain flat washers. Put a screw and washer at each of the six marks on your board. Do not screw them in all of the way yet so that you have room to put in the antenna elements.
Put the inner bends of the antenna elements under the washers. The bend in the wire should go inside the screw. Tighten down the end screws, but leave a little room in the center screws to attach the balun.
Place the spades of the balun around the center screws and under the antenna elements. The ends of the balun should be in direct contact with the antenna elements. Tighten down the center screws.
The main assembly of your antenna is now complete. Depending on your needs you may or may not want to add a reflector to your antenna. A reflector will help give stronger reception for weak stations in the direction that the antenna is pointing. But on the down side, it will block the signal of stations behind the antenna. Without a reflector, I was able to get 26 channels with this antenna. But I added the reflector to
increase the signal on a particular station that I wanted to get from over 50 miles away. After adding the reflector, I am only getting 22 stations. Skip down to see a simple base that t hat you can stand up this antenna with.
I built my reflector from a thin piece of masonite measuring 24" by 33". To begin, draw two lines down the center of the board running length wise. The lines should be 1" apart.
Tape aluminum foil to the front of the reflector. Use the lines to keep a space between the foil on the left and the foil on the right.
Make two spacers to support the reflector from 1x4 pine. Cut these spacers to 3 1/4" long. Screw the spacers to the top and bottom of the reflector as shown. s hown.
I did the final assembly of my antenna in the attic because it was easier to get the pieces up there that way. To attach the reflector, screw through the front of the antenna into the spacers on the reflector. The aluminum foil on the reflector should be centered behind the reflector elements.
Attach the cable to your television to the balun on the antenna. The cable should go down between the antenna elements and not in front of them. I used some zip ties to hold the cable in place.
The base of the antenna was made by attaching the remaining piece of 1x4 to the bottom of the antenna. For stability, you could screw this to a rafter or two. Mine is just balanced there since wind is not a concern in my attic.
PVC SBGH With Reflector This is the first Gray-Hoverman Antenna that I built. The frame is 1/2" PVC fitted together without glue. The antenna elements are secured to the frame using zip ties. The reflector is made from poster board and aluminum foil.
2. Folded Dipole Antenna
This is the third antenna that I built but it is also the simplest, both in terms of design and construction. It is also the design that impressed me the most. A folded dipole is a very basic antenna design. Often, it is combined with other elements such as reflectors to produce more powerful antennas. But I wanted to see how it would perform in its most basic form since that would be easy for anyone to build. This antenna took me less than 10 minutes to build and I was surprised to find that after placing this in my attic, I was able to bring in 13 digital channels. This included the four major network channels (ABC, CBS, NBC and FOX), some independents and a few news and weather channels. The nearest tower is 8.8 miles from my house and the furthest is 51.6 miles away! (See the broadcast tower information for my area at TV Fool. Fool.) While this did not perform as well as my GrayHoverman Antenna, Antenna , I would recommend it as a first build. If it gets all of the channels that you want, you won't need to take the time to build something more complex unless you want to.
Parts List: •
1 Metal Coat Hanger
•
2 Screws
•
1 Balun - This transformer is needed to adapt the antenna's signal to your T.V.'s coax input. It is available from many sources. I got mine at my local Walmart for less than $5. See pictures below.
•
1 Wood Board - For this build I used a pine 1x2 that I had laying around my garage.
•
1 Bracket - This is used to mount and pivot the antenna. Again, I used one that I had laying around.
Assembly Photos
Homemade DTV Antenna In June of 2009 the government-mandated switch to digital television (DTV) went into effect in the United States. With this change comes more channels along with DVDquality picture and sound. To enjoy these benefits of DTV, all you need is a converter box (or a TV with a built-in ATSC tuner) tuner) and a decent antenna. This page explains how you can build a great little lit tle antenna for not a lot of money and start enjoying overthe-air digital.
My Digital Conversion Experience When I first found out about over-the-air digital TV I was pretty excited. I had heard that DTV broadcasts were in the UHF band and UHF channels had always been among the best analog reception for me. So I went out and bought a converter box and hooked it up to a cheap UHF loop antenna. Amazingly enough I got many channels with good clarity. I had a few had dropouts here and there, but overall the
picture quality was better than cable. Then I noticed a couple channels were missing. After visiting antennaweb.org antennaweb.org,, I found out why. It turns out that not all digital TV is broadcast in the UHF band. In fact, in Chicago there are two stations (CBS2 and ABC7 ABC7)) that still broadcast over VHF VHF.. Since a VHF antenna was required, I resorted to adding a pair of rabbit ears to my UHF loop. So now I've got free over-the-air digital TV, but at the expense of a really hokey-looking antenna atop my entertainment center. I started searching the Internet for a better solution. There are several space-age looking "HDTV-ready" antennas out there, but surprisingly many of them were only designed for the UHF band. I managed to find a few that advertised VHF and UHF coverage, but upon closer inspection the VHF band was pulled in by a set of rabbit ears.
Building My Own I have a pretty solid background in electronics, electronics , so I decided to try my hand at building an antenna from scratch. I figured that with a little research, I could make one that's better performing and less obtrusive than what's commercially available. I started by researching some basic designs and finally settled on the half-wave folded dipole. I chose this antenna design for several reasons. •
Easy to understand, well documented antenna design.
•
Can be built with readily-available 14 gauge copper wire. (The same stuff used deliver electricity to household outlets.)
•
Good bandwidth covering a full octave.
•
300 Ohm impedance connects to commonly available matching transformers.
Design Criteria Digital TV is broadcast in two bands, VHF High (RF channels 7-13) and a portion of UHF (RF channels 14 - 51). According to information at cgsnetwork.com cgsnetwork.com,, these channels correspond to frequencies 174 - 216 MHz and 470 - 698 MHz respectively. Looking at the DTV broadcast frequencies, I determined that it's just not possible to build a single folded dipole that performs well over the entire range. This did not surprise me however, since analog TV always required using two different antennas, one for VHF and another for UHF. So I decided to build two antennas and use an old-fashioned VHF/UHF combiner to bring the signals together.
The UHF Antenna I started with the UHF antenna. I figured that being smaller it would be easier to construct and I wouldn't waste much wire if it took me a couple tries to get it right. The first thing to do is calculate the measurements of the folded dipole. I chose the center of the UHF band for my target frequency of 584 MHz. The formula to calculate the length of a folded dipole is taken from the ARRL Handbook For Radio Communications that I checked out from my local library.
l
= 468 /
where
l
f
is length in feet and
f
is frequency in Hertz
or
l
= 5616 /
where
l
f
is length in inches and
f
is frequency in Hertz
Using the formula, I found that the length of antenna required for my UHF target frequency is 5616 / 584 or 9.616 inches. Since measuring tapes have fractions and not decimals, I rounded to 9 5/8 inches. The distance separating the wires in a folded dipole design ( s), although not extremely critical, should be small compared to it's length. I decided to wrap the wire around a screwdriver handle to form the curves, so s is about 3/4 inch. So now the trick is to take all of the measurements and build an actual antenna. I start by cutting a 20 1/4 inch (2l plus an extra inch) length of 14 gauge wire and marking the center of it. The extra inch is so I can make curves on the end and still end up with the correct width. From the center marking I measure out 5 1/16 inches in either direction, a quarter of the length of wire, and mark these distances as well. These last two marks show me roughly where the ends of my dipole will be.
The VHF Antenna Designing the VHF antenna is the same process as the UHF antenna except that the center frequency is 195 MHz. This translates to a length ( l) of about 24 3/4 inches. I'll
be using the same screwdriver handle to form curves on the ends of the dipole so again I added an extra inch to the length of wire to compensate. That makes the total length of wire 25 1/4 inches with a center mark at 12 7/8 inches and quarter-length marks at 6 7/16 inches from the ends.
Putting It All Together To form the folded dipole elements, I take my straight piece of wire and place one of the quarter-length marks on top of my screwdriver handle. I then gently bend the wire around the screwdriver handle, lining up the end of the wire with the center marking. I repeat the process with the other side making sure the two ends have a gap of about 1/8 inch between them. After a little adjustment, I've got two nice-looking folded dipoles ready for mounting. Since I have two antenna elements, I need to combine the signals. I also need to convert the 300 Ohm antenna elements to the 75 Ohm input of my DTV converter box. I can accomplish both of these tasks with a relatively inexpensive UHF/VHF 300 Ohm combiner from Radio Shack. Shack . I can simply cram the ends of my folded dipoles under the screw terminals of the combiner and tighten them down so that the UHF element is stacked on top of the VHF element. If I want to get a little fancier, I could solder on some fork terminals first. The only thing left to tackle is hooking it up to the converter. It's not very practical to attach the 75 Ohm output of the UHF/VHF combiner directly onto the converter box. That leaves me a couple options. I can get a cable to attach it, but it will need a male F-connector on one end and a female F connector on the other end. That's not a real common item as most cables are male on both ends. My other option is to rig something up with a gender changer. changer . I can plug one end into the UHF/VHF combiner and attach any standard coax cable to the other end.
Enjoying Over-The-Air Digital Now that the antenna is done, I simply place it on top of my entertainment center, cable it to my converter box and point it toward the broadcast towers in my area. Most of the channels come in very well, but I do live 30 miles from the towers and occasionally there is some break-up in the picture of weaker stations. Fortunately, I was able to boost my signal strength with an inexpensive 12dB RF amplifier from a local home improvement store.
All-in-all I am very happy with my antenna design. It has several advantages: •
Good performance
•
Fairly inexpensive
•
Relatively easy to build
•
Much less obtrusive than rabbit ears
Best of all, I learned a lot while building it, plus I get bragging rights for doing it myself.
3. Bow Tie Antenna The Bow Tie Antenna is a simple design that can be found in many variations on the web. It can be made with a 2x4, some coat hangers, aluminum foil and a few other common parts. While very inexpensive to build, this design is able to pull in stations from 45 and 50 miles away. (See the broadcast tower information for my area at TV Fool..) Fool
I had originally intended to include some detailed build instructions here. But since building my Folded Dipole Antenna, Antenna , I have decided that I would not be recommending this design. Not that it is a bad design, but I feel that the Folded Dipole or my Gray-Hoverman are better DIY projects for someone not wanting to make a hobby of antenna building. Check out the pages for those antennas for the pros and cons of each design. If you really want to build a bow tie antenna, a quick web search will find MANY interesting designs. Here is a diagram and a photo of the Bow Tie that I built. In the third photo, you can see that I added a reflector to mine. This is just a thin piece of scrap plywood wrapped in aluminum foil mounted four inches behind the bow tie elements.
4. Television Frequency Table This table is the frequency chart for the US designated Television Channels. There are both VHF and UHF channels listed. This is listed as a matter of information only and is part of the public domain information of the government.
GENERAL TELEVISION FREQUENCIES Sub CATV Band - T7 - T13
7 - 48 MHz
VHF Band - Ch. 2 - 13
54 - 216 MHz
Low Band - VHF Ch. 2 - 6
59 - 88 MHz
Mid Band - UHF Ch. 14 – 22 - UHF Ch. 95 - 99
121 - 174 MHz 91 - 120 MHz
High Band - VHF Ch. 7 - 13
175 - 216 MHz
Super Band - CATV Ch. 23 - 36
216 - 300 MHz
Hyper Band - CATV Ch. 37 - 62
300 - 456 MHz
Ultra Band - CATV Ch. 63 - 158
457 - 1002 MHz
UHF Band Ch.14 - 83 - CATV Ch. 63 - 158 70 - 1002 MHz MHz
VHF TELEVISION FREQUENCIES BAND
CH #
FREQUENCY
BAND
CH #
FREQUENCY
VHF LOW
2
54-60 MHz
VHF HIGH
7
174-180 MHz
VHF LOW
3
60-66 MHz
VHF HIGH
8
180-186 MHz
VHF LOW
4
66-72 MHz
VHF HIGH
9
186-192 MHz
VHF LOW
5
76-82 MHz
VHF HIGH
10
192-198 MHz
VHF LOW
6
82-88 MHz
VHF HIGH
11
198-204 MHz
VHF HIGH
12
204-210 MHz
VHF HIGH
13
210-216 MHz
UHF TELEVISION FREQUENCIES CH #
FREQUENCY
CH #
FREQUENCY
CH #
FREQUENCY
14
470-476 MHz
38
614-620 MHz
62
758-764 MHz
15
476-482 MHz
39
620-626 MHz
63
764-770 MHz
16
482-488 MHz
40
626-632 MHz
64
770-776 MHz
17
488-494 MHz
41
632-638 MHz
65
776-782 MHz
18
494-500 MHz
42
638-644 MHz
66
782-788 MHz
19
500-506 MHz
43
644-650 MHz
67
788-794 MHz
20
506-512 MHz
44
650-656 MHz
68
794-800 MHz
21
512-518 MHz
45
656-662 MHz
69
800-806 MHz
22
518-524 MHz
46
662-668 MHz
70
806-812 MHz
23
524-530 MHz
47
668-674 MHz
71
812-818 MHz
24
530-536 MHz
48
674-680 MHz
72
818-824 MHz
25
536-542 MHz
49
680-686 MHz
73
824-830 MHz
26
542-548 MHz
50
686-692 MHz
74
830-836 MHz
27
548-554 MHz
51
692-698 MHz
75
836-842 MHz
28
554-560 MHz
52
698-704 MHz
76
842-848 MHz
CH #
FREQUENCY
CH #
FREQUENCY
CH #
FREQUENCY
29
560-566 MHz
53
704-710 MHz
77
848-854 MHz
30
566-572 MHz
54
710-716 MHz
78
854-860 MHz
31
572-578 MHz
55
716-722 MHz
79
860-866 MHz
32
578-584 MHz
56
722-728 MHz
80
866-872 MHz
33
584-590 MHz
57
728-734 MHz
81
872-878 MHz
34
590-596 MHz
58
734-740 MHz
82
878-884 MHz
35
596-602 MHz
59
740-746 MHz
83
884-890 MHz
36
602-608 MHz
60
746-752 MHz
37
608-614 MHz
61
752-758 MHz
CATV CHANNELS CATV Channel
Video Frequency
Sound Frequency
SUB-Band CATV Channels T7
7.0000
11.5000
T8
13.0000
17.5000
T9
19.0000
23.5000
T10
25.0000
29.5000
T11
31.0000
35.5000
T12
37.0000
41.5000
T13
43.0000
47.5000
LOW BAND 2
55.2500
59.7500
3
61.2500
65.7500
4
67.2500
71.7500
5
77.2500
81.7500
6
83.2500
87.7500
CATV Channel
Video Frequency
Sound Frequency
MID BAND 95
91.2500
95.7500
96
97.2500
101.7500
97
103.2500
107.7500
98
109.2750
113.7750
99
115.2750
119.7750
14
121.2625
125.7625
15
127.2625
131.7625
16
133.2625
137.7625
17
139.2500
143.7500
18
145.2500
149.7500
19
151.2500
155.7500
20
157.2500
161.7500
21
163.2500
167.7500
22
169.2500
173.7500
HIGH BAND 7
175.2500
179.7500
8
181.2500
185.7500
9
187.2500
191.7500
10
193.2500
197.7500
11
199.2500
203.7500
12
205.2500
209.7500
13
211.2500
215.7500
SUPER BAND 23
217.2500
221.7500
24
223.2500
227.7500
25
229.2625
233.7625
26
235.2625
239.7625
CATV Channel
Video Frequency
Sound Frequency
27
241.2625
245.7625
28
247.2625
251.7625
29
253.2625
257.7625
30
259.2625
263.7625
31
265.2625
269.7625
32
271.2625
275.7625
33
277.2625
281.7625
34
283.2625
287.7625
35
289.2625
293.7625
36
295.2625
299.7625
HYPER BAND 37
301.2625
305.7625
38
307.2625
311.7625
39
313.2625
317.7625
40
319.2625
323.7625
41
325.2625
329.7625
42
331.2750
335.7750
43
337.2625
341.7625
44
343.2625
347.7625
45
349.2625
353.7625
46
355.2625
359.7625
47
361.2625
365.7625
48
367.2625
371.7625
49
373.2625
377.7625
50
379.2625
383.7625
51
385.2625
389.7625
52
391.2625
395.7625
53
397.2625
401.7625
CATV Channel
Video Frequency
Sound Frequency
54
403.2500
407.7500
55
409.2500
413.7500
56
415.2500
419.7500
57
421.2500
425.7500
58
427.2500
431.7500
59
433.2500
437.7500
60
439.2500
443.7500
61
445.2500
449.7500
62
451.2500
455.7500
ULTRA BAND 63
457.2500
461.7500
64
463.2500
467.7500
65
469.2500
473.7500
66
475.2500
479.7500
67
481.2500
485.7500
68
487.2500
491.7500
69
493.2500
497.7500
70
499.2500
503.7500
71
505.2500
509.7500
72
511.2500
515.7500
73
517.2500
521.7500
74
523.2500
527.7500
75
529.2500
533.7500
76
535.2500
539.7500
77
541.2500
545.7500
78
547.2500
551.7500
79
553.2500
557.7500
80
559.2500
563.7500
CATV Channel
Video Frequency
Sound Frequency
81
565.2500
569.7500
82
571.2500
575.7500
83
577.2500
581.7500
84
583.2500
587.7500
85
589.2500
593.7500
86
595.2500
599.7500
87
601.2500
605.7500
88
607.2500
611.7500
89
613.2500
617.7500
90
619.2500
623.7500
91
625.2500
629.7500
92
631.2500
635.7500
93
637.2500
641.7500
94
643.2500
647.7500
100
649.2500
653.7500
101
655.2500
659.7500
102
661.2500
665.7500
103
667.2500
671.7500
104
673.2500
677.7500
105
679.2500
683.7500
106
685.2500
689.7500
107
691.2500
695.7500
108
697.2500
701.7500
109
703.2500
707.7500
110
709.2500
713.7500
111
715.2500
719.7500
112
721.2500
725.7500
113
727.2500
731.7500
CATV Channel
Video Frequency
Sound Frequency
114
733.2500
737.7500
115
739.2500
743.7500
116
745.2500
749.7500
117
751.2500
755.7500
118
757.2500
761.7500
119
763.2500
767.7500
120
769.2500
773.7500
121
775.2500
779.7500
122
781.2500
785.7500
123
787.2500
791.7500
124
793.2500
797.7500
125
799.2500
803.7500
126
805.2500
809.7500
127
811.2500
815.7500
128
817.2500
821.7500
129
823.2500
827.7500
130
829.2500
833.7500
131
835.2500
839.7500
132
841.2500
845.7500
133
847.2500
851.7500
134
853.2500
857.7500
135
859.2500
863.7500
136
865.2500
869.7500
137
871.2500
875.7500
138
877.2500
881.7500
139
883.2500
887.7500
140
889.2500
893.7500
141
895.2500
899.7500
CATV Channel
Video Frequency
Sound Frequency
142
901.2500
905.7500
143
907.2500
911.7500
144
913.2500
917.7500
145
919.2500
923.7500
146
925.2500
929.7500
147
931.2500
935.7500
148
937.2500
941.7500
149
943.2500
947.7500
150
949.2500
953.7500
151
955.2500
959.7500
152
961.2500
965.7500
153
967.2500
971.7500
154
973.2500
977.7500
155
979.2500
983.7500
156
985.2500
989.7500
157
991.2500
995.7500
158
997.2500
1001.7500
Frequencies Used by Wireless Cable Frequency Range
Number of Type of Channel Channels Service Groups
Channel Bandwidth (MHz)
2,150 - 2,162 MHz
2
MDS
6
2,305 - 2,320 MHz
2
WCS
5 & 10
2,345 - 2,360 MHz
2
WCS
5 & 10
2,500 - 2,596 MHz
16
ITFS
ABC&D
6
2.596 - 2,644 MHz
8
MMDS
E&F
6
2,644 - 2,686 MHz
4
ITFS
G
6
1,2,2(A)
2,644 - 2,686 MHz
3
2,686 - 2,689.875 MHz 31*
MMDS
H
6
MMDS
Response Channels 0.125
* Each channel's bandwidth is 125 KHz, and does not carry video.
NTSC CONTOURS Channels
Grade B Grade A City Grade Service Contour Service Contour Service Contour
Channels 2 through 6
47 dBu
68 dBu
74 dBu
Channels 7 through 13
56 dBu
71 dBu
77 dBu
Channels 14 through 69
64 dBu
74 dBu
80 dBu
DIGITAL TV CONTOURS Channels
Grade B Grade A City Grade Service Contour Service Contour Service Contour
Channels 2 through 6
- dBu
- dBu
35 dBu
Channels 7 through 13
- dBu
- dBu
43 dBu
Channels 14 through 69
- dBu
- dBu
48 dBu
