Transcript
Fro nt view of the Atlas 210 solid state transceiver. Despite the small size of the unit, a II controls are fu ll size a nd easily me nipul ated.
CQ Reviews: The Atlas 210 and 215 88B Transceivers BY J OHN SCHULTZ.* W 2E EY
A
who happened to see W6QK I at the ARRL Conve ntion in New Yo r k City last year o pe ra ting the Atlas 180 tra nsceive r from a portable battery pack must su rely ha ve been impressed. The da y of a fu lly sol id-state , portable h .f. rig o f reasonable power had arrived . Both the Atlas 180 a nd the battery pack cou ld be taken under o ne arm and on e would have a completel y po rtab le sta tio n runn ing 180 watts PEP inp ut on 160. RO. 40. a nd 20 m eters! Her b J o h nso n, W 6QKI. the President o f Ali as Rad io . is not new to introducing exciting prod uct s to a mate u r radio. He was o ne of the founders o f Swan Rad io and acti ve in de veloping its produ ct lin e for m an y yea rs . The 180 was the first Atla s p rodu ct to come o n th e m ar ket a nd it. as well as the current 21 0 /215 model s. borrows heavil y from ci rc u itry developed for milit ary /indu strial co m rn unications applications. Most o f the ci rcu itry used was developed by SourhCom Inte rna tiona l for U!'oC in th eir m ilita ry tr an sceiver AN / URC · 78. NYRODY
General Spees Perhaps the first im pre ssion o ne gets about the 210 o r 21 5 is that it is sma ll. A s can be seen in the photograph. it is easi ly held in o ne hand . The d imensions a rc 9 14" wide, 31h " high a nd 9 '4" deep o veral l. Th e we igh t is 8 Ibs. Contained in side thi s litt le pack age is a complete transcei ver of e xceptiona l per formance. »c / o C Q . J4 Vanderventer Ave.• POri \Vashing-
ton. NY 11050. 22
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Th e major specs a s Atla s claim s them for the 21 0 and 21 5 a re as follows: Band COIWtlRe: 11 0 model: 3700-40 50, 70007350. 14.000- 14. 350. 2 1.1 00-2 1.4 50 and 28.400· 19.1 00 k Hz. The 2 I5 del ete ' 10 meters but add' 1800-1000 k Hz, The restric ted cove rage of some ba nds is du e onl y to the basic 350 kHz v.f.o. used , Full coverage o f 80. 15 and 10 is possible with a n external v.I.o. withou t any ot her mod ificat ions. M od es o f Operatio n: Ll .s.b., l.s.b. and c .w, Po wer ln put t Output: 200 wall s PEP or c.w, in p UI a nd mi ni m um of 80- 100 wa tts PEP o r c .w, ou tput o n a ll ba nds (e xce pt 120 wall s input on 10 met ers fo r the 210 ) . RTTY and SSTV modes are not specified. Loud l mpedancc: 50 o hms resistive fo r rated power ou tpu t. Infinite V.S.W . r. p rotection for o utpu t tran sistors. Carrier ami Sideband Suppression : 50- 60 d b at 1000 Hz. Harm on ic Sup pression: 35 db below peak out put . R ecei ver S ensinvitv: 0 .3 p,V for 10 db sig na l/ no ise ratio . Se icctlvit y: C rysta l latt ice filter at 55 20 k Hz i.f.. 8 pol e. l mage R ejectio n: 60 db or bette r. Aud io Ou tpu t: 2 watts ma x. int o built-in speaker. M etering. Reads S units o n rece ive, am p lifier collector cu rre nt (0· 16 am ps) o n transmit. Po wer R equirem ents: 12-14 v.d .c. Draws 0 .2
to 0.4 amps in receive mode a nd 16 a m ps peak in transmit m ode. The a bove specs are no t a ll there is to, the 210 /215, but a re presented m ainl y to illu strat e that the 2 I 0 /2 I5 clai ms to be much more th an ju st a co m pro mise type transceive r. E xcept for band cove rage, t he 210 /21 5 cla ims to be as
good o r bett er than the 25-60 lb. tube-type tran scei ve rs m o st of us ha ve o n o u r o perati ng ta ble s. Being co m pletely solid-sta te, t he 21 0 /215 m ake s usc of broadba nd lun in g ci rcuit s for both the receiver a nd transmi tter fun c t ion s. There a re no lu ni ng cont ro ls e xce pt for t he v.f.o. In spite o f the broadba nd tuning o f the rece ive r in put circuits. a clai med design fe a ture is "exc eptional " im mu ni ty to overload a nd cross mod ul at ion wh ich m atc he s or exceeds t he best tu be-t ype designs . O bviously. At la s was w illi ng to sta nd by its clai m si nce the usua l "fudgefact or" in put atte nua to r co mmon 10 solid-Slate rece iver des igns is not pre -er n. The 21 0 /215 emph a sizes modul ar design . N ot a ll o f the PC boards
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Basie Cireuitry Figure I sho ws a block diagram of the sta ge a r ra nge me n t. The heart of the c irc ui t ry is the du al use of th e i .f. amplifi er /mixer cha in in both th e re cei ve a nd tran smit modes . In the re ceive mode . th e 2 10 / 2 15 perfo rm s as a sing le conversion rece iver with an i.f. o f 5.520 kHz. The sig na l is int rod uced vi a a se t of ba nd swi tched lo w pass filters to :'1 se t of band swit ched 4 pole bandpa ss re cei ver in put fill e rs and then directl y to th e fi rst ba la nced d iode mixer with0111 r .f', pre arnpl ifi cation . Th e v.f.o. signal. which o pe ra tes 5~2() a bove the i.f. o n 160. 80 a nd 4() a nd 55 20 kH z below it o n o t he r ba nds . is a lso inje cted into the m ixe r T he resu lt ant i.f. signa l t ravels th rou gh Q,,,,. a lo w no ise a m plifi e r stage. a nd thence via th e i .f . filler a nd Ie i.f. a m plifier to the seco nd ba la nced diode mixer. injecte d wit h the c rysta l co nt rolled carr ier o sci l la to r signa l. acts as a produ ct d etector. Norm al a .f. a m plification foll o ws via two l C st ages. I n the tran smi t m ode. the fir st bal anced d iode mixer se rves as th e usu al diod e ring modu lator be ing fed with the transmi t te r au d io a nd carr ier oscil la tor sig na ls. Sid ebo ard se lec t io n is accom plished by th e i.f. fi ller pl u s use o f th e desired ca r rier osci llato r frequency fo r u .s.b. o r t.s. b . T he second m ixe r serves a s a fre quency conversion stage a nd with inject ion o f the v.f.o . signal and i.f, signa l produces a signa l o ut put
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Fig. 2-The most unusual featu re of the Atla s 210/215 is the use of a d iode balanced mixer, without r.f. p re-omplification, in the receiver, followed by Q low-noise l.L amplifier.
on the desired frequency band. The tr ansmitter input filters following the second mi xer select the mixe r o utput. Further s.s.b, signal amplification is straight-th rough at the o pe ra ting freq uency via Q ~I throu gh Q rm- T he power amplifier stages a re broad-banded and coupled to the a nte nna via th e bundswitched lo w pass fii lters. T hese du al half-wa ve fi lters h ave cu to tT f requencies from about Y.z to severa l M H z above the high end of each ba nd. C .w. o peration is accomplishe d by shifting o ne of the carrier osci llator crysta l's f requen cy into the i.f. filter passba nd by ca pacitive lo ading. An offset of about 600 Hz is provided to preve nt lea p-frogging o n c.w. contacts. A combined amplified a .g.c.la.l.c. line acts o n the IC i.I. a mplifier stage Q:!O ... A .g.c. actio n is audio derived and the a.l.c. action, a lthough not obvious from fig. 1. is actua lly derived from a built-i n S.W. r. bridge. Norm al a .l.c. voltage is detected by the forward power pickup o f the bridge. Excess reflected power picku p acts to cut-off the i.f. chain th us reduci ng dr ive and p rotecting the power tra nsistors. C.w. keyi ng is performed by the i.f. to cut-off via th is same a .g.c.la.l.c. chain. The "device cou nt" doesn't appear impressive--onl y 4 I'C's and 17 transistors! But, mo st of them a re worki ng all the time! The success of the scheme depends mainly on two th ings those balanced diode mixers a nd the switching o f the v.f.o. a nd carrier oscillator signals between the m ixers. Bo th techniques are d iscussed la ter in some det a il. 24
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Reeeiver Performance In put signals fro m th e antenna a re first routed th rough the ba ndswitched low pass fi lters which alwa ys remain in the a ntenna line, then via the ba ndswi tched receiver input bandpass fillers and fi nally to the double bala nced first mi xer ( fig. 2 ) . The fi rst mi xer is simila r to the seco nd o ne in the use o f I N4148 diodes a nd lrifil ar wound toroid tran sformers for input a nd output co u pling. Interestingly enough , the d iodes are no t so me super-soph isticated type s but silico n types selling at abou t 30 cen ts each from G .E. The first mix e r o utp ut goes to a 5520 kH z i.f. tran sfo rm er a nd then to the first am plifying de vice in the receive chai n-a 2N3866. M anual r.f. ga in contro l is a pplied to th is stage via a po tentiometer which varies the forward bias. The outpu t of thi s stage goes first to the 8 pole crystal i.f. filter and th en to a conve ntio na l MCI 350C second i.f. a mplifier which has a.g.c. applied. W ith all the passive co mponents o n the inpu t of the recei ve line one m ight imagi ne that the se nsitivity wo uld be rather Jess th an spectacular. Atlas cla ims a m in im u m sensitivity o f 0.3 uv fo r 10 db signal/ no ise ratio . The measu red results were: 160 .25 pv 15 .28 pv 80 .20 pv 10 .33 pV 40 . 15pv 20 .is sv One ca n conve rt the JlV figures fo r a 20 db signal/ no ise ratio by multipl ying the m b y a p-
I
proximately 3 times. The 210 or 215 appears as sensitive or more sensitive than most transceivers on the market which do have an r.f. preamplifier stage. T he general impression that one gets when operating the 2 10 or 2 J 5 in receive is how similar the bands sound as to when using a direct conversion receiver. The main impression is the remarkable lack of signal "garbage" and clutter generated usually by front end overload and poor image rejection. Signals seem to pop out o f a quiet background.
The 8 pole fi lter is extremely effective. Numbers and measurement figures on such things as front-end overload and filter bandwidth are certainly interesting, and if everyone were consistent in measurement, useful for comparison purposes. But, they can a~o rapidly loose meaning when trying to describe actual opera ting expe rie nces. The 210/2 15 was tried extensive ly in the Saturday/Sunday morning mayhem which exists On the phone bands on the East coast. Probably no receiver in this world will ever be able to offer enough selectivity, sensitivity and overload protection to separate a ll th e DX from the locals and unscramble all the W's fro m eac h other. But, the 210 /2 15 perfor med as well as an expensive communications receiver using mechanical filters and costing several times the price of a 21 0 or 215. For c.w. reception under extreme QRM , ad ditional selectivity is undoubtedl y desirable. Atlas at the moment does not provide a c.w. fi lter. However, they did bring the leads fro m the installed s.s.b. filter to an accessory socket on the rear of the 210 /215. So, one could break the i.f. cha in a t this point and insert additional selectivity. A 2 pole crystal filter with 100.200 Hz bandwidth can be worked in series with the s.s.b, filter. This should provide excellent c.w. se lectiv ity at low cost. T he audio de rived a.g.c. used works very well. A signal input range of from 5 p.v to 3 volts produces only a 4 db change in the audio output level. The only thing in the audio ch ain that might deserve a bit of criticism is the builtin 3" speaker. On the unit s tested, it had a slightly tinny ring to it. There is a provision for the plug-in o f an external speaker. T he 2 watts of audio out put is more than suffi cient. even for mobile use. The "feel" of the tu ning on a transceiver is another one of those things which defies definition by a set of numbers but yet determines very mu ch over a period of time whether one is going to enjoy using the unit. The feel of the tu ning on the 210/215 is very good. Smooth and with no back lash. The tuning rate on all bands is 15 kH z/revolution except on 160 where it is about 9 kHz and on 10 where it is 30 kHz/rev. For c.w. and with a sharp c.w. i.f. filter installed, the tu ning rate would be excellent. The
main dial is calibrated every 5 kHz. With the slow tuning rate one can easily count down to 1 kHz and spaced ma rkers on the main tuning knob make the job easier. A 100 kHz calibra tor is built-in and produces strong markers. Why 50 cents or so more wasn't spent to include an I'C divider 10 obtain markers every 25 kHz is not clear. It is a sim ple thing, of course, to add such a divider 10 the calibrator if desired. Transmitter Performance The same i.f. chain used in the receive mode is used to develop the s.s.b . signal. The basic d.s.b, signal is generated in the first low-noise, diode, bal anced mixer at either 5520 kHz or 5523.3 kHz, depending on the sideband chosen. U.s.b. is automatically produced on 20, 15 and 10 meters and I.s.b. on 40, 80 and 160. A fro nt pa nel switch allows for opposite sideband selection when desired. The "switching arou nd" of the first mixer to function either as the re ceiver input mixer in the receive mode or as the d.s.b. balanced modul ator in the transmit mode is accomplished in a simple but ingenuous fashion. Referring to fig . 2 which shows the fi rst mixer in detail, it can be seen how the switching of inputs is accomplished. In the receive mode, the "T" line going to R I " . is at zero volts. Diode switch D I06 is open a nd allows receiver input signal to go to ~Ol" The local oscillator (v.f.o.) signal is routed to L i o l via C "llI and R 1f16• The transmitter a.f. input coupled via r.f. choke Lint has been grou nded via a diode switch similar to D I ~ on another PC board. On tra nsmit, the "T" line is at + 13 volts and diode switch D UJ6 shorts OUi the receive input signal. The local oscillator input becomes the carrier oscillator input (via another switching arrangement described later ) . The transmitter a.f, input is fed to the diode modulator from the microphone amplifier. A similar type of switching arrangement converts the second mixer to either a product detector on receive or m ixer for the purpose of translating the 5520 kHz s.s.b. sig nal to the de sired output band on transmit. The v.f.o, is a three stage affair with two buffer stages. Its freque ncy range is switched dependi ng upon the band in use. Stability is excellent, being in the order of 100 Hz per hour after warmup. The 8-pole crystal filter following QIOl perform s the single side-band selection. Atl as makes a definite point of the fact that they chose a filter with a 6 db bandwidth of 2.7 kHz to handle an audio respo nse of 300 to 3000 Hz rather than a 2.4 or 2.1 kHz wide filter. They point out that "i t has been convincingly proven that tran smission and reception o f the audio frequencies between 2400 and 3000 Hz provides a substantial improvement in real signal readability:' There might be some argument May,1975
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on thi s point. All th at can be sa id here is that reports of excellent audio qu ality and signal pu nch were received. Atlas re commends the use of a quality microphone with a smooth response from 300 to 3000 Hz. o ne exa m ple of wh ich m ight be the Shure 404 C. The second m ixer converts th e 5520 kH z s.s. b. signal to the o u tput ba nd fr equency. It might be interesting to see at thi s po int how the v.f.o. a nd ca r rier oscill at or signa ls are switched back and fo rth to eit her the first or seco nd mix er. Th e dia gram of the "switch" is shown in fig . 3. Essentiall y. it is a solid-state eq uivale n t of a d .p.d.t . switch using FET's as th e switching elements. The tran smitter " key line" is a t + J 3 volt s o n receive and at 0 volts o n tra nsmit. The opposite is true fo r the "T" line sho wn. On re ceive. Q"" l and Q",..-, arc pinched off by about + I 0 vol Is. Q :~ Cl and Q.,.., are cond ucting wi th only about + 0.7 volt s o n their gat es. T hus th e v .I.o. signa l fl o ws to mi xer # I a nd the ca rrie r o scill a tor sig na l 10 m ixer #2. On tra nsm it. the op povi te h appens w ith Q,.ct a nd Q,... pinched o ff, e tc. It's a hand y circuit to remember for u se as a so lid-state lo w-le vel switch. Followin g tran slation to th e output fre qu en cy. the real powe r bu ildup co mes in the stages co ntai ned in a separate powe r amplifier modu le ( rea lly a large heat sink e nclosure) mounted o n the rea r of the tran sceiver. The r.f, buildup is via a 4044 6 as a preamplifi er. a 2N5490 a s driver a nd two 2N 64 59's ' IS final s. A ll stages a re coupl ed b y broa d- band tran sTran'n'utter key line
+13 v.
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formers. The nominal 12 volt input power line to the transceiver is pe rm anently connected to the latter two stages. Only the low-level 12 volt circuits are affected by the front-pa nel on-off swi tc h . A bi as switch ing transistor associated with th e driver a nd final sta ges assu res th at th ey draw no significant cu rre nt unle ss the lowle vel 12 vo lt circuits are activa ted . The final stage is rated as 200 watts input (except on to) o n s.s.b . a nd c.w. a nd a minimum output of 80 watts. Measurements m ad e sho wed the following for o ut pu t at 13.6 v.d.c. r' 160 9 3 wa lls 15 - 90 walls 80 - 102 walls 10 - 42 wall s 40 90 wall s 20 84 wa lls RTTY a nd SST V modes were not tested but it would appea r th at the 2 10 o r 215 cou ld run a t a reduced power in put o f a rou nd 100 o n these mod es. Those w ho have seen so lid -sta te 2 watt tra nsmitt e rs com p le tely ruin nearby TV reception beca use o f thei r high harm onic co llec to r cu rrent s and ou t put. m a y wo nder wh at 200 watt s of solid-state can do . Not m uch in th is case. T h rough the shield ing provided by the co mpletel y en closed powe r amplifier modu le and th e use o f ba ndsw itc hed low-pass filters harmonic rad iat ion is 35 d b d o wn from peak o utpu t. Th is is sufficient for mobi le u se bu t for home usc in fri nge a rea more harm oni c a tte nua tio n will probabl y be necessary. the sa me as wit h a lmos t any tran sce iver on the market today. A far more sign ifica nt item to watc h when using the 210 /215 (o r a ny ne w' solid-state. broad -ba nd tra nsmitte r) is tha t o f ha vin g a n ('xa ct a nten na /t ra ns m issio n line mat ch to the ou t pu t o f the tran smitter. A tube type rig wit h a n adj us ta ble pi -network output ca n match a sm all b ut d efi nite ra nge o f im pedances. Ho wever, wit h a broadba nd . so lid-stat e r ig there is no adjustable p i-ne twork a nd fi g. 4 shows wh at ha ppens fa the output power of a rig suc h as the 2 10 /2 15 . Mo st mo bile a nte nnas o n the m ark et today do not provide a non-re act ive load of 50 o hm s at the ir reso na nt fre que ncy . Th e y ma y provid e a " no m ina l" 50 o hm lo ad but tha t won't do fo r solid-state rigs. Th e refore, when usin g a rig: suc h as th e 210 /215 for mobile a pplica tio ns, it mu st be matched far mo re closely to the antenn a used . Atl as m arkets a toro id. b roadba nd m a tc hin g transfo rm er ( the MT-I ) wh ich con vert s from 50 o h ms to selectab le impedances o f 13 . 18 or 2 3 o hms. Th ese imped ances are closer to th e "real " o nes presented by mo st ce nte r load ed mobil e a nten nas. The taps may have to be c ha nged whe n ba nds a re sw itch ed . I
Values sho wn are worst-case figures fo r two unit s tested whe re bot h unit s cove r the sa me b.IOU . Same as for receive r sensitivity.
N o min a l Po we r O u tp u t ( WClfH)
SW .R. 1.0 I. I .......•...... 1.2 ........ . 1.3 .....•........ 1.5 2 .0 .... l .11
.
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Fig. 4 -0utput p ower vs. s.w. r. for the Atla s 21 0/ 215 transceiver. Note the pa rticu la rly sha rp decrec se in o utpu t p o we r when s.w.r. rises above i .s . 1. Th~\ chara cte ristic is common to b roadband solid-stct e konsceive rs using h iq h-s.w. r. p rotec tive circu it ry .
F o r home stat ion o peration . the am ateur uving a ...im ple dipole: or beam will atmo... t rer tu inly req uire a matchi n g ne two r k bet ween the ba refoot :!101:!1 5 a nd hi s a ntenna on ::! O. 40 or SO me te rs 10 achieve maxi mum power 6u t p u t ove r the en tire band. wo rk ing into a linea r ge ne ra lly w ill pre-em no problem if it as the u vual in p u t broa dba nd P i or L netwo r k , lrho ugh th ese ne two rk ... m a y have 10 be opt im ze d for 50 o h m v ins tead of t he usua l slo ppy olc run cc s \\ hi ch tu be-type t ra nsceiver s ca n cco rnmoda tc . Ex ce ssive v.w.r. p rote ction a n d a .l.c . o pera io n in the :!I O/ :!15 is pro vided by a b u il t-in e flec to mc tc r or .... \V. L brid ge usin g a to roid ia l ran sfo r rne r as t he pick u p c le me n t on the tra nsnitt er OUlpU I l ine . Vo lta ge: pic kup p ro po rt iona l a the refle cted po wer leve l is u sed to redu ce .f. d ri ve v ia th e n.e .c.va .l .c. loo p . Several test s o nfir me d t he effec ti ve ness of thi .. ci rcuit in -ol v in g no-loud co ndi t io ns . Tu ne-up is no r ma lly acco m pli... hcd in the ' . W . m ode a nd in thi , m o d e th e fr ont-panel ic ro p ho ne gai n co n t rol is a u toma tic a lly wit ch ed to fu nction a .. ca r r ier level in sertion -o n t ro l. T he a .t .c . contro l is broug h t out as a ront pa nel co n t ro l a' a dua l pote nt io meter .rrun ge rn ent w hh the mic ropho ne gain potenio mcrcr Thi .. a r ra nge m ent allow s .10 o p timum euin g of the a .l.c. le vel to be achieved for -ach band . Sisb. sign al rcoort -, co n fi r med cl ean a nd .rr icul nte modul ation . H ig he r order distortion rodu ct s a re a t lea...t 30-35 d b dow n. C .w . ke yn g, \\ hich i-; ncco r uptivhed b y mean s o f CUI-off if the iJ. c ha in. ...how no sig n of cl ick s . No .w, monbor i... built in although one c an he :lsily a d de d . S witc h in g between re ceive a nd tran smi t odes on v.s.b. is con vent ion al. E ith er a PIT utton on a m icrophone. o r the front panel unctio n switch ca n be used . Unfortun ate ly. h in gs a re nOI so ... imple o f c .w. U sing the sa me ron t pa nel switc h one would have to go from F:C th rough -TRAN S and to cw a nd the n bac k
ea ch time the receive / tra nsmit f unc t io n is perform ed . Th is arrange meru is certain ly no t ac cept a bl e for a Jo t of c.w. a ct ivity. F o rtun ate ly , a ll th e lin es \\ h ich hav e to be switched a re terminated a lso as po in ts On the a ccessory so c ket s o n t he rea r of th e transceiver. Semibrea k-in. for in... ta nce, cou ld be ach ie ved b y an external ke yc r w hich activa ted a t ime dela y circuit and relay w h ich acco m plished the necessa r y swi tch in g or one coul d run a li ne to a min ia ture d .p.d .t . toggle swi tc h sc i next to o r o n the bave of the ke y to U~ for m anu a l reccive / t ra n...m it ~ \\ itc hing . Frequent reference has bee n m a de to the various so ckets o n the re ar of the :!10 12 15 . Specificall y. there are so c ke ts fo r r.f. output. exte rnal speaker /headphone .... microphone . c.w. key. evterrut oscillator and a not her sim ply m arked .. acce......ory ...ockc t." It nccessc... linea r a m plifie r swit ching. u.l. c . in p u t fro m a linea r. provision for c.w. fi lte r insertion in the i.f. c ha in and ju...1 about every operati ng vo ltage ,IOU ... witch ing f un ct ion .
Wiring and Construction T h e co n... tru ctio n a nd wiring can be " lied a<.; excelle n t. The: wirin g was e xa m ined ca refut ty a nd no truce o f po or wo r k ma ns hi p co uld be fo und . T he: pl ug-i n boards arc he ld lig ht ly in pla ce by brac ke ts o r o ther su p po rt mean s. A n ice feature abo ut a ll o f the co n tro ls. switc hes a nd soc kets is th at th ey a rc ...cre w m ou n ted inste a d o f r iveted . The refo re eve n if so met h ing (cO llfill ll('d 0 11 f' lI g t '
fi5 1
,I
At the rear of the Atlas 2 10 /2 15. t he brood -ba nd power am p lifier hinges d o wn to p ro vid e a cce ss to PA wiring . The toroid-stock-co res fo r the broa d band transformers are viso ble towards the left. Missing from this view a re the plug-in PC boa rds and the d ru m dial whi ch si ts above the d iol cord p ulle y at the top ce nte r.
MaV,1975
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de tector was now a t hand for s.s.b, reception. And. most im portant, the cost of building such a hand-crafted receiver had sky-rocketed, and it seemed impractical, o r rash, to continue with the project. Regretfully, it was shelved.
L'envoi J im Millen has been in the " wireless" business for 50 years. The Millen Co mpany continues. a lthough' a ll o f the pre-war co m petito rs o f years ago have long since disa ppeared. No large com munications company that made amateur com m unication recei vers pre-war is in the business today! James Millen ran his first advertiseme nt in 1922 in Radio N ews. T oday-c-over fifty years later- if yo u look in the advertising pages o f C Q. you will see an advertisement for his present company ! CQ. and the au thor of thi s artic le. salute a great radio a mateur and pioneer, Jim Millen. and his fa mous HRO receiver, the fi rst modem commu nication receiver! •
Announcements
[from page 8 J
Th e y will o pera te o n 40 meters, ph on e a nd cw : 20 m eters, phon e a nd cw; a n d 2 me te r FM . Th e Novice Bands wi ll be kept act ive o n 40. Shows a nd ex hib its wi ll be all day in Van Cor rland Park in The Bron x. • Trenton, Tennessee - Th e An n ual Humboldt ARC Harnfest is Sun da y. Ma y l St h a t Sha dy Acres City Par k , Tre nt o n , T N. For info r ma tio n, co n tac t : Hu gh Wa rd law, WB4S LI, 2678 Co le Dr., Humboldt TN 38 34 3. • Knoxville, Tennessee - The Radio Ama teu r Club o f Kno xvill e is pleased to a nno unce that it 's a nnual Gr ea ter Knoxv ille Ha mfest will be he ld o n May 24 t h a n d 25t h 197 5. Ac tivit ies will be lo ca t ed in t he Jaco bs Build in g a t Ch ilho wee Park, Kno xvill e. Mo re info rmatio n for SAS E fr om WA4 BT K, 131 6 Kirb y Road ., Knoxv ille , TN 3 791 9. • Rochester, New York - T he FCC wi ll co nd uc t a ma teu r rad io exa mi na tions a t the Western New Yor k Hamfest , in Ro ch est er . N Y, o n Sa t urda y. Ma y 3 1st for Ge nera l a n d hi gh er class licen ses. Ex a minat ions requirin g a code t est ( 13 or 20 wpm) wi ll begin at 10 a m. T hose not requiri ng a cod e test (a dva nced class) will begin a t 1 pm. Applica ti o ns shou ld be sub mi tted with th e $4. 00 filin g f ee n o later Ih a n May 23rd t o the FCC, Ro om 100 5 C usto mhou se, Second an d Chestnu t Sts. , Philadelphia. PA 191 0 6.• Burlington_ Kentucky - The Ke nt uc ky HA M-O-R AMA will ta ke pl ace Sun day, J une I, a t th e Bo o ne Coun ty Fai rgroun ds, Bur lingto n, Kentuc ky . Loca ted 10 m iles sout h o f Cinci nnat i, Ohio nea r 1· 7 5. Adva nce ti c ket s, $ 1. 50 , fo r informa t ion. contact: WA80GS, 638 1 Mullen Road , Cinc inna l i, O H 45239 . • Ogl£lsby, Illino is - T he S ta rved Roc k Radio Club's a nnual lI am fest is June 1st a t t he Burea u Cou nty Fairgroun ds in Princet on . A long SASE is r eq uir ed f or infor matio n a n/or advance regislrat ion . w ri te, G.E. Keith W9 M KSJW9QLZ. R F D no. I, Box 171 , Oglesby , I L 6 1348. (81 5) 667-46 14 . • Winfield, PA - The Twe tvt h A n nual Pen n-Central Hamfest will be held b y the Will iam s• port a nd Milton clu bs o n Su nday , June 1st, 19 75
a t th e Union Town ship Volunt eer Fire Co . grounds o n rout e 15 in Winfi eld. PA. For more information , write, West Uranch Amateur Radio Association, c/o All an Owe n, WA 30WT. 2 901 Hi ghland , Ave. , Mont oursville , PA 17 754.
CQ Reviews Atlas [from page 27] shou ld gi ve o ut eventuall y, a simple repair or re placement effort is a ll that is needed.
Inst ructio n Manual The inst ru ct ion manual starts off well enough with some general circuit description. hints for mo bile installatio n and then the basic schematics, but PC board layo uts and complete parts num bering for replacement purposes are lacki ng.
Accessory Items Desk mo unted co nsoles wh ich include a built-in a .c. power su pply and two types of mo bile mou nts are available ( o ne a completel y plug-in affair and the other a su ppo rt bracket with manu al plu g-in o f exte rnal cables) . The MT-I mobile wh ip matching tra ns fo rmer is also availa ble. Other accessories still to be produced are a n accesso ry v.f.o., a semi-break in keyer/m on itor uni t and possibly a c.w. filter.
Summary The 21 0 o r 2 15 is not a tran sceiver loaded with frill s but its basic perfo rmance is very good to o utstand ing. It is definitely s.s.b o ri ent ed for the mobile amateur bUI there is no re ason why it co uld not be adapted to become the heart of a home statio n also for both s.s.b. and c.w. For portable operatio n with a nic-cad battery pack it opens up possibilities for portable o pera tio n about which one carr only specula te . The frills that are missing can be added if o ne is a bit hand y with circuit work. For instance. o ne could easily enough put in digital fre quency readout via a preprogrammed co unte r since onl y one frequency conversion is involved. Plenty of room exists if the di al drum is removed. Th e disad vantage is that a TIL cou nter will draw mu ch more current than the receiver alo ne a nd th is may restrict the versatilit y of the transceiver for portable use. A c.w, moni tor and VOX are easy to install or can be used as external accesso ries. The restricted coverage o n some ba nds can be shifted to cover desired portions of a ba nd by retuning the internal v.f.o. Full coverage of any ba nd can be ac hieved by an ex terna l v.f.o . since o nly the range of the inte rnal v.f.o. ( 350 kHz o n most bands) restricts ind iv idual band coverage. Th e broad-band receiver /transmitter circ uits full y co ver each band. T he Atlas Model s 2 10 and 215 are ava ilable from dealers throu ghout the USA, and a re manu factured domesticall y by Atlas Radio Inc., 490 Via Del Norte, Ocean side , CA 92054. Either model costs $599. Power supply console for 117 volt operation is $ 129. -W2EEY May,1975
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