Yaesu HF RTX
CQ Reviews: The Yaesu Musen FTdx 570 S.S.H./C.W. Transceiver BY WILFRED M. SCHERER,* W2AEF I T is pretty d ifficult 10 m ake a good piece of gear even better, except to add a few extra Iacil itics. T his is what the Yaesu Musen people have primarily done with the FTdx570 transceiver, the successor to the popular FTdx560. Since th e la tter h as been reviewed in a previou s issue of CQ,I we shall not go into a ll the det ail s o n the normal features, techn ical as pects and performance which also appl y to the FTdx570. For these it is therefore suggested that reference be made 10 the earl ier review. Nevertheless, a recap of the main th ings to be expected of these tra nsceivers mi ght be in order as follows : Transceivc operation with s.s.b. (u.s. b, o r l.s.b. ) o r c .w. is provided with full coverage of th e 3.5-28 mH z a mate ur bands, each o ver a 500 kHz ra nge with the identical lineartun ing ra te calibrated in I kH z ste ps. The transmitter input power is rated at 560 watts p.e .p, with s.s.b. and 500 wa tts d.c. fo r c .w, on all bands. Other features include : 2.4 k Hz selectivity ( with exira position for an optional 600 Hz · Technical Director, CQ. I"CQ Reviews the Yaesu Musen Ffdx560 Transceiver," CQ, May 1970, p. 34. c.w. filter) ; 10 mHz WWV band; provisions fo r two additional auxiliary 500 kH z segmenls between 3.5 and 30 mHz; 25 and 100 kHz calibrating m arkers; high-ratio tunin g control wit h spinner-type knob; fas t- o r slowa .g.c.; built-in v.o.x. with panel-located sensitivi ty control; manual or v.o.x-type c.w, break-i n; adjustab le c.w, side tone oscillator; ::t:5 kHz receiver off-set tuning; fro nt-panel switch for changing between internal or ex- ternal v.t.o.'s (external v.f.o. is optional accessory) 10 permit qu ick change betwee n common or independenI freq uency control of receiver and transm itter sections; a.l.c.; full metering for recei ver S-units, transmitter a .l.c. level, p.a. cathode currenI o r relative po wer output ; 8- and 600-o hm a.f. o utputs ; phone-patch input ; socket for 6-m eter transverter accesso ry ; built-in 117 /2 20 v.a.c, power supply. The b.f. o., v. I.o. and calibrat- ing setups are transistori zed ; o therwise, vacu- urn tubes are used throughout. In addition to these th e Model FTdx5 70 incorporates a built-in speaker, a coo ling fan and a true tra nsistorized noise blanker. New Details T he built-in speaker. which elim inates the The Ya e su Mu sen FTdx570 s.s.b. yc. w. tran sceiver. , · _. ..~~ .. ··.-~-.·. ·:r.:F i ~· . ..: · :·,'·. ... ·· · Septemb e r, 1972 · CO · 39 Rear top view of the FTdx570 showing the exhaust fan a t the back of the p .c . enclosure the only open - ings of which are at the interior sides to enable heat to also be drawn from the entire unit. The noise blanker is installed on a circuit board at the top of the v.l.e. at the upper cente r. need for a n addit ional u nit, faces downward at the bottom of the ca binet. Such an arra ngement normall y might impair intelligibil ity, but du e to the tilt-up type ca se for the trans- ceiver and the part icular response character- istics o f the spea ker, easy and excellent read- ability is maintained. The cooli ng fa n is located a t the rea r o f the p.a . com partme nt. It is an exhaust type th at draws out warm air fro m not only the p.a .. but also from o ther sectio ns of the un it fo r whic h strategically loca ted slo ts a re provided a l the p.a, enclosure. At the same time the fan draws cool air into the unit. The noi se blanker su pplants the original NOise Amp 2SC7110 Pulse Amp 2 S1<34( FE T Ga te Conlrol 2SC7 11 0 318 0lltHZ I .F. Amp 2SC 71 10 Ba lanced Ga le [2l1StOO7 To I. F. F iller Fig . l - Block diagram for the noise blanker used in the FTd x5 70. N oise pulses, obtained from the mixer output, are a mplified, detected and appropriately sha pe d to operate the gate a t the filter input. The gate employs two diodes in a ba lanced setup that eliminates switching transients. This provides quieter operation. a .f.-type noise limiter. A block d iagram of the setu p is shown at fig. I. Although it is a somewhat conventional lineup, the ac tual eir- cuitry and constants a re such that make it one o f the m ost su perb performing jobs we've run across, not only fantastically eliminating im- pulse noise, but also preventing desensitiza- lion of the receiver by noise pulses that o ther- wise wou ld decrease the rece iver gain through the a .g.c. action created by the noise pul ses. An improvement over early FTdx5 60 models is a change at the product detector whereby cleaner a udio qualit y is o bta ined with high in put-signa l levels. A cha nge also has been made in the c.w, wa ve-shaping that produces more desira ble keying character- ·IstI·C S. ·~ The 600 Hz ( @ 6 db) c.w. filter is excep- tionall y shar p for o ne of its type, since it has very steep skirts that re su lt in a 2: I sha pe fa ctor with a 60 db bandwidth of only 1.2 kHz. Its o verall effectiveness is thus better th an some of the 400-500 H z fiilters we've en- cou nte red with sha pe factors usually in the o rde r of 4. 1. The filter is a uto ma tically switched in when the transceiver is set up for c.w, opera tion. This filter is an optio na l fac- to ry-insta lled accesso ry; however, it can be su pplied for installation as a do-it- yourself kit. With a receiver sens itivity o f 0.3 uv or better for 10 db S +N /N on all bands, an unwanted-sideband su ppression of at least 50 db (a t I kHz ), th e excellenl selectivity with the o ptio na l c.w. filter. a n output of at least 300 wa lls p.e.p. o n s.s.b. a nd 260 wa tts o n C.W., plus all the o the r fea tu res of the FTdx- 570 mak e it a transceiver th at gives you a hi gh-performing an d flexible setup to meet the essentia l needs o f today's a ma teu r-rad io commun ications. The FTdx 570 is priced at 5549.95, com- plete, incl ud ing all crystals for complete coverage of the 28 m Hz band. All you need to get o n any band is a mic (or ke y) and an- tenna. The optional c.w, filter, factory-in- sta lled o r as a kit, is 5 39.95. These arc pro- ducts of Yae su Musen, Ltd., T okyo, Japan, a nd a re m arketed in the U.S.A. exclusivel y by Spectronics, 1491 E. 28th Street, Signal Hill, California 90806. - W2A EF :"'The given changes also are included in later models of the F'I'dx 560. SUBSCRIBE TODAY L-- I 40 · CQ · Septembe r, 1972Adobe Acrobat 8.0 Paper Capture Plug-in Adobe Acrobat 8.0