The Icom R

The Icom R70 fs a general-coverage communications receiver covering a frequency range- of 100 kHz to30 MHz. Newly introduced to the market IE made me anxious to review it and share my impressions.

As wilh mosi hams, I could not resist the urge to unpack the radio and begin using it immediately without, of course, reading the instruction manual. It Is because of this ease of use that I have such good things to say about ft

The IC-R70 has a front panel that is both uncluttered and functional All controls are clearly marked, and after studying it For a tew minutes I became aware of the radio's versatility. Bringing it to life was extremely easy, wilh just iwo connections, power cable and antenna The 117/235-V-ac input is standard, with optional 13,6 V dc available. It is also internally modifiable to 100/200/ 220 V ac. The built-in speaker eliminated hunting around the shack for the phones or thai bullet-riddled speaker that usually turns up.

The receiver is a quad conversion unit with its first i-f a! 70.4515 MHz. The second i-f is at 9.0115 MHz. Without an antenna, I tuned across about all of Its range, observing the birdies, The few I found at expected places were, however, far below the level of signals present with the antenna connected.

Ail of the initial testing took place on the ham bands using my triband beam. Twenty meters provided the kind of signals i was looking for, especially at the lower portion of the phone band. The R70 features a Pass-Band-Tuning {PBT) system allowing you to narrow Ihe width of frequencies passing through the crystal filter The passband can be moved up to 500 Hz from the upper or lower side in SSB mode (2.7 kHz in the AM mode). With the control in the OFF position, the passband is 2.3 kHz wide in SSB mode and 6 kHz in the AM mode. Using this control, I was able to hear stations that could not be received by using the notch control alone. No information was published as to the shift and depth of the notch filter, but it seems as effective as any other I've used.

White the Pet system took some get ting used to, the frequency and mode selection did not. The radio has three select-abie-tuning rates, 1 kHz, 100 Hz, and 10 Hz. These controls are located to the right of the tuning knob and, with a little practice, I could quickly zero in on the desired frequency. The one thing that did get a little confusing was the fact that the frequency does not roll over. Increasing from, say- 7.&99.9 kHz returned you to 7.000 0 and not on to 8.000.0 kHz, This, however, turned out to be a time-saver when tuning from high to low ends of a band or vice versa. A LOCK push-button afso is provided to disable the tuning knob, preventing accidental changes in frequency.

To the left of the tuning knob are three controls marked BAND UP. DOWN, and

Icom *s R70 receiver.

HAWUGENERAL These are used to Increment or decrement (he most signihcant digit c! the frequency dtspla* ,Aihen an the general-coverage mode Whan in the nam coverage mode these conirots step you through t&Om, 80m. 40m etc skipping all of the frequencies in between 11 does stop at the new 10-, 18- and 15-mhi bands also.

Other Iront-panEi cOnlroEs include cw (wide and narrow—500 Hih SSB. RTTV, AM and FM (with the optional module]. There is a separate FUNCTION push but-lon designed to select the sideband opposite Iho one you are In and select the narrow CW Tiller, The receiver automatically chooses upper or tower sideband depending on whether the frequency is above or below 9 MHz. A SQUELCH control also is provided, obviously getting used more for the FM mode than any otner M did work very .veil in SSfi mode, however bul only on strong stations. its action «a* dependent on ihe age timing, and in me slow setting took quite a while to open {or close). I cannot see any real need for it except m tne FM mode.

The frequency-display panel includes a 7-digit readout with tOOHz resolution; it displays which mode and wio ls in use. There are two vfe's (hat Ci+n De loaded with the current Irequency mlormation and called independently of each other An RIT control is provided to shift the received frequency ±800 Hi from Ihe displayed frequency. No Indication is given on the display except for a status LED shoeing that the control is in use. A useful feature is the fact that the RIT control is automatically disabled once the main tuning knob Is moved Itt ir be re-enabled anytime by depressing the push-hutton This assures you mat you are receiving me displayed frequency

A buifcki preei-r:p ifier ar-. aitenuator y*iich-seiec1abie irom the froni panel Claimed attenuation is 20 dB. with no mention of ine amount q1 preamptilication. Judging from the S-metet indication it seems to be in the order of 5 dB» An age se-lectoi permits a liminq of fasi o; siowL or OFF ThJs I found morn than adequate tor all types of communications using the fixed rates. A swllchable noise blanker proved very effective In both the available narrow or wide settings. 11 al 'io seemed very elective with woodpecker type noise. Wo decrease in signal levels was perceived with the noise blanker switched in

The built-in speaker provided good-quahly reproduction of an types of signals. in the AM mode. SVi broadcast stations *ere very enjoyable to listen to without Ihe tvgh-pitched sound that one m^ht expect frorr such a sma<i speake' In an> event. an external speaker jack is provided should you wish to use it. as well as a recorder output Jack me latter outputs an audio level independent of Ihe volume-control selling.

All hough adven ised as a general-coverage communications receiver, rear^panel conned ors are provided to allow easy use ol the unit with □ transmitter or transceiver. The lC-R7Gt>as a mute input allowing it to bo quieted during transmit. Transmitted signals can be heard in the receiver, however by using tls monitor function. The volume ot the monitored signal can be adjusied with the front panel control.

The rear-pane -ccesscr> socket can aiSPte ^seo toconfci VHF and UHFcon-friers The switching ¿rrangemen! is covered In suffictem detail in the manual Also available on iho- ate essory socket ts an output from ihe receiver's detector stage Tnis output is ai a tmed level regardless of the volume or gain settings. It Is intended to be used to drive a ftty terminal unit. Qlher rea- panel connectors include a scope oulp-.it from Ihe first M

l70.<5l&MHzf This would be useful for us mg a panoramic-type display

Rear-panel antenna connectors are of both ihe PL-259 type and spring clip type The former is intended for approximately 160 meters aid up. while the srngte Aire input is trended for the AM broadcast band fcolow T ne CG-3* .a: ccnnec :or .s desiQnod !or a 6C Ohm-impedance antenna system, and no specifications are give" lor the long-wire connector. No provisions are made lor antenna matching leaving it en-lirely up to the user to determine optimum performance

My final comments deal with Ihe instruction manual and schematic;; As one who likes to maintain his own equipment I found the documentation included lotal-ly lacking in content. The manual is an excellent operating instruction manual, but very iii:te informahon is given on circuit description uc ublesltooling, and general maintenance Tne schematics -ire ot the type snowing detai" of individual tircuns. Out interconnections are - ague.

In summary, i would consider this receiver an excellent value. Us periormance would ma^e it suitable for the banning nam. as a standby receiver for th'.L shack, Ot lo fill the void between hamming ¿nd casual listening, lis usefulness for Field Day or emergency communications cannot be overlooked. Also, I don't ihink the new or seasoned SWl couiu find iaull with lis performance—again making It a worthwhile addition to the shack. My wile, on the other handh did noi like ihe radio; that was after I told her that I would like to have one.

For further Informahon, contact icom Amenai. inc . 2112 T 7Si* Ave W£. Be/te-vue 96004: 206¡ 454*8153

Walt LewandowsM WA2VSN Spot lord N H

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