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the band. If you use both phone and CW, it might be well to make the design frequency near center of the band. Likewise, the design freq uency may be made in the CW segment if you desire. Getting back to the swr measurements, you will note that at the antenna, or the base of the matching section, if one is used, the reflected power is nil across the greater portion of the design frequency, making the true swr unit. Next remove the swr meter from the driven element and reconnect the transmission line. There is no need to cut the transmission line to any particular length-just use random length to suit your purpose. Insert the swr meter at the transmitter end next and again make the full swr meter measurements across the band every 50 kHz as previously done with the swr meter at the antenna. Again, plot the curve on graph paper and note the similarity of the curves. Due to a multitude of factors, the transmitter end of the transmission line swr readings will tend to be somewhat lower at the band end extremes. A dummy load may be substituted for the antenna. Heath's "Cantenna" is a good and inexpensive one. The Waters dummy load power meter is excellent, but more expensive. An rf (thermo-couple) ammeter in the transmission line at the transmitter is worth its weight in gold and much more preferable to an in-line swr meter at the same point. Good Western Electric and G.E. rf ammeters may be purchased on the sur plus market for less than five dollars. After tuning and loading the transmitter to either the dummy load or the antenna there will be no change in transmission line current when switched from one to the other and no retuning of the transmitter should be necessary. This indicates as nearly as possible with available equipment whether your antenna is nonreactive or near pure resistive. If a Bird Model 43 in-line oscillator/monitor ~_.- 8.- • mak•• an audibl. ton. to ....onitor the RF of any CW transmitt., from ,..;:'::":' ." IOM.... to I K.... lr IOOK~ to IOOOMc. 1- -' uling only an 8~ pi~kup ant.nn.. 11111- • un be ••If.trigg..... for ,od. ~;;::i::.:;:::n~·~~dg~7:,:7~~ • .id. in tuning up lr t.lting RF o.dll.to••r:d pow.r ,ir'uih. • # tr.n.iltor, 2 diod. ~i.~uit. 'P""." ton••diu.t. A.A p.n,.II, t••t I••d., 8' .nt., lr m.,neti, ba... • ,.bin.t i. Ib taug. M.," lr ~I••r •"Wi••d .luminum, 3.4 • 2.3 • 1.2~ US m.d.lr gun.nt.ed For I y.... 1495 ,ompl., ppd ,...a&can. ••nd a ch.~k or m.e, lold by mall only James Research campany',dep'l: AR-M 11 schermerhorn Sl., brodkl n n.y.11201 wattmeter or equivalent is available. some interesting overall efficiency measurements may be made. Insert the wattmeter at the antenna feed point and adjust the transmitter to a given plate power input. On all further measurements keep the transmitter adjusted to the same power input. At frequencies near the design frequency the antenna is nonreactive and there is no reflected power and the overall efficiency is indicated. For instance, we adjust the transmitter to 500 watts de input, the wattmeter indicates no reflected power and forward power reads 300 watts (with grounded grid amplifiers and 100 watts of power output from the exciter, the final amplifier should be adjusted to 360 watts input as the output from the 100 watts from the exciter should appear in the output to the transmission line). The overall efficiency from plate power input to actual power output to the antenna would be 60%. This includes normal transmission line losses, impedance transfer from final amplifier, etc. This percentage may seem high, but is quite attainable with good linear amplifier design and proper matching of transmission line to a resonant antenna. Now tune the transmit· ter to the same power, but to freq uencies at which the antenna is nonresonant. Note the difference in forward power and reflected power. Subtract the reflected power from the forward power and figure the efficiency percentage. Make these same percentage measurements every 50 kHz over the band as was done with the swr curve. That does it! There lies the reason why it is still preferred to have an antenna with less frequency excursion and higher efficiency than one of a compromise nature. The preceeding procedures are not intended to be the "ultimate" but will afford the "working ham" a less expensive and time-consuming method of getting the most from his multi-element quad antenna. Although the reference is to a four element quad on a thirty foot boom, the same approach may be used with a two or six element quad. The forward gain and FIB ration will be as good if not better than the average when tuned in this method. Work has been going on for more than three years to broad-band a multi-element quad and yet retain a minimum reactive load over the entire band, Success seems just around the corner, but the last ten years working with the multi-element quad has taken its toll. W4AZK 34 73 MAGAZINE
The lassie 36 With Patent Approved' Classic Feed System' You've been hearing about the Classic Feed System and its phenomenal success in three-element configurations. Now-in response to repeated requests-this revolutionary new matching system, Balanced Capacitive Matching. has been incorporated into the original sixelement configuration of DX-proven TA-36 to create the new Classic 36. This tri-band beam, rated for maximum legal power cn lO, 15,and 20 meters, features the Classic coax-fed balanced element for more efficient beam performance. increased bandwidth. and maximum gain. As the latest addition to the world-famous Mosley Trap Master line of amateur antennas. the Classic 36 offers: frequently-imitated, never-improved-upon Mosley Trap- Master Traps; automatic bandswitching by means of exclusively designed, high-impedance parallel resonant Trap Circuits; weather-tested Trap-Master construction. Satisfied TA-36 owners can convert their beams to the Classic 36 with the new TA36/CL36 Conversion Kit. The Mosley name is your guarantee: Mosley bui Ids quality antennas and stands behind them. Write factory direct for complete specifications and performance data, including VSWR curves and gain figures. 'Pat. No. 3419872 Dept. 181A ••Is" .Jhc. .6'0 N. L.INDBERGH BL.VD•• BRIDGETON MO. 63042
Page 1 and 2: WORLD'S LARGEST INDEPENDENT HAM MAG
Page 3 and 4: MAGAZINE 73 Magazine 11'104 , May 1
Page 5 and 6: .. .. .... .", , , .. ...... ."'"".
Page 7 and 8: Here are several hams who have achi
Page 9 and 10: New 500-Watt 5-Bander from NRCI You
Page 11 and 12: , I ....- , 0 0 ====j .- .'Q ' 0, .
Page 13 and 14: ohm coaxial cable off ce nte r will
Page 15 and 16: Now your transmitter can work . •
Page 17 and 18: e AC and DC SUPPLI ES BU ILT IN! e5
Page 19 and 20: If you're thinking about boning up
Page 21 and 22: y t hose whom I thought were of hig
Page 23 and 24: (Sometimes, when I make like an SWL
Page 25 and 26: -e,-,"' '.-- j - - , . .... .' 1 ,.
Page 27 and 28: preselectors, it is a fine investme
Page 29 and 30: WHAT IS THE BEST ". CO'. TO SET ,,'
Page 31 and 32: I ,~ - Gel more receiver than you p
Page 33: the boom, shorting all loops so tha
Page 37 and 38: look (electrical) at il. I took my
Page 39 and 40: ROHN, as the largest tower manufaot
Page 41 and 42: • ,~, • • • ••• 1>00"
Page 43 and 44: transmission line or the rf voltage
Page 45 and 46: sumed. A signal generator of suffic
Page 47 and 48: may not have enough rf available to
Page 49 and 50: cuitry developed through the earlie
Page 51 and 52: The Super SS Clifford Klinert 520 D
Page 53 and 54: present one, a boornless quad, was
Page 55 and 56: HOWARD W. SAMS Famous Editors & Eng
Page 57 and 58: declared that they " are and have s
Page 59 and 60: and the state regulating agencies.
Page 61 and 62: '0' '" '0. Fig. 2. T he direct r ea
Page 63 and 64: 2 A 7/ I 1/2 ). ----~I/~--- 2 1/ 8
Page 65 and 66: 0000 O' A"'( TE ll " • "'''''' 10
Page 67 and 68: Add This Simple Decimal Readout to
Page 69 and 70: THE STELLAR - CASE STATION IS NOW A
Page 71 and 72: \ 1/ r------- - TO l(lollTlil " P I
Page 73 and 74: Step 4: In actual practice, VBE wil
Page 75 and 76: F ig. 1A (II SPLIC E C E ~ T E R CO
Page 77 and 78: How to Fly YOur Kite M. B. Crowley,
Page 79 and 80: Boulder Antenna 18 28 38 48 58 Tabl
Page 81 and 82: MH z. and consequently less paths a
Page 83: 30 a ~ ~ , I , I ~ V ' - 0 z I .' <
Page 86 and 87:
0 2 1!i0 'O!iV 8+ F ig. 2 . GAG7 Am
Page 88 and 89:
I Telephone Beeper The following is
Page 90 and 91:
the 20's and 30's the phone transmi
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• A Kilowatt Dummy Antenna •
Page 94 and 95:
Mini-Bomb • Bill Brown 11".pSYK 2
Page 96 and 97:
• DX'ing rom Joseph D. Burn ett ,
Page 98 and 99:
Kalashi Nose, KH6IJ/l J0 Cam bridge
Page 100 and 101:
Getting Your Extra Class License Pa
Page 102 and 103:
- stage o f the game, it's a major
Page 104 and 105:
e-radiation produced by the molecul
Page 106 and 107:
and direction usually undergo chang
Page 108 and 109:
Just to complicate things, most aur
Page 110 and 111:
----- ---- o F[EO------- - - ---- -
Page 112 and 113:
corner reflector is sometimes incor
Page 114 and 115:
known that almost any spaci ng (wit
Page 116 and 117:
NEW BOOKS Electronics for Technicia
Page 118 and 119:
Economy Ed Baker, W0EDO 993 7 Truma
Page 120 and 121:
4 x 150 Sockets Larry Jack, WA3AQS
Page 122 and 123:
Alan Shawsmith. V K 4SS 35 Whynol S
Page 124 and 125:
Handbook is easy to use and accurat
Page 126 and 127:
TEST E UIPMENT 'IIi\IATUHE TEST L\U
Page 128 and 129:
SQUEEZE ACTION TOOL A MUST FOR THE
Page 130 and 131:
Adapting A Mobile Antenna System or
Page 132 and 133:
LETTERS This is in response to your
Page 134 and 135:
Also, I thought that the ta x-exemp
Page 136 and 137:
--r..ta U 8H NEW G&G CATALOG! MILIT
Page 138 and 139:
we would retain responsibility for
Page 140 and 141:
LARGEST SELECTION In United State.
Page 142 and 143:
HAMFEST sponsored by Lancaster & Fa
Page 144 and 145:
JOHN MESHNA JR. 19 ALLERTON. ST., L
Page 146 and 147:
LIBERTY PAYS MORE! LIBERTY OFFERS M
Page 148:
NEW DRAKE MODEL • TR·B 6-M SIDEB
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