Retro Review: Icom IC-745 HF Transceiver
Introduction:
The IC-745 is a 1980's vintage all band HF transceiver with digital readout and general coverage receive. It covers all amateur bands from 160m to 10m (including WARC bands) using SSB, CW and RTTY, with FM as an option, and is capable of receiving from 100 kHz to 30 MHz in all modes, including AM.
First Impressions.
The IC-745 is an impressive looking HF transceiver, with a large number of knobs that look daunting at first, but are grouped logically on the front panel. The display is a vacuum fluroescent display, which is easy to read from a wide range of angles at a fair distance. The radio itself is quite large, and more suited to base station use, but as it runs off 13.8V DC, it is capable of being used mobile as well.
The manual is quite thick and goes into a fair bit of detail of the verious operations of the rig, but like other manuals of this era, suffers from the occasional bit of "Jinglish" (poorly translated Japanese). One major bonus is that full schematic diagrams came with my IC-745, which is a big plus in my book. Schematics are something that's rare with radios these days.
Inside, the IC-745 is solidly constructed and made for easy servicing. The various boards are clearly labelled in the schematics, PCB layouts (also supplied) and inside the radio.
Another feature that immediately made itself evident was the inclusion of a transverter socket, which was perfect for interfacing to a 2m transverter that I already owned.
On air:
At the outset, it's worth mentioning that my QTH is a particularly poor one for HF operation. In addition to being limited to mobile whips for antennas, there is a high level of noise from the computers in the shack, and the TV. This is quite a test for the noise filtering abailities of any receiver.
Despite the obvious limitations of this QTH, the Icom's receiver performs very well. The IF shift/passband tuning and notch filter work well to remove noise and heterodynes from a received signal, and the noise blanker, which was designed to cope with interference such as the Russian 'woodpecker', that was common in the 1980s, cleans up most forms of pulse noise. This ability of the noise blanker was particularly evident during a trip around VK7, where 40 metres was used to communicate with amateurs back home in Melbourne. With the noise blanker in, there was no sign of the car's ignition noise, which was quite loud when the noise blanker was off.
As a general coverage receiver, the IC-745 pulls in shortwave stations and local AM broadcast stations well, with good audio.
On transmit, audio reports were generally quite good. Not quite the well rounded audio of a Kenwood, but nevertheless generally good. The speech processor received mixed reports. On poor 80m paths, it seemed to improve intelligibility, but on marginal VHF paths, using a transverter, everyone found the uncompressed audio to be more readable. The transmitter produces 100W of RF power on all bands except 10m, where the factory setting is 50W, which can be altered by a simple modification to 100W.
My IC-745 had the FM option fitted, so I was able to try the rig out on the FM repeaters. Reports were very good, but on FM, it is necessary to reduce the mic gain to a very low level for best audio. The relative audio gains of FM and SSB are not well matched. During a few sporadic E openings, the Adelaide 10m repeater was tried with good results. Repeater operation is achieved by using the 2 VFOs in split mode. A little clumsy to setup, but it achieves the desired result.
AM transmit is not supported, but there is a modification for the IC-745, which enables AM transmit. After performing this mod, the IC-745 produces up to around 40W of clean, well rounded AM. Just the thing for the 80m AM net.
For those considering a second hand purchase, there is one thing to be aware of. The IC-745, like several other rigs of this age, use a battery backed memory board, which stores vital information, such as band limits, in addition to memory data. If this battery goes bad, not only are memories lost, but the radio will be unusable. There are two ways to fix this problem - order a replacement board from Icom, or a third party EPROM board, which is a permanent fix for this problem (it only uses RAM for memory data).
During the VK7 trip mentioned above, the IC-745 gave an excellent account of itself. As previously mentioned, received signals were excellent, with the help of the noise blanker. On transmit, the signal from the mobile was clearly received in Melbourne, 500 - 600 km away at all stages of the journey. At one point, a bad patch lead meant that I was unable to use an ATU with the antenna. The resulting 3:1 VSWR was not a problem for the transmitter, and didn't seem to cause it much distress.
I also regularly use the IC-745 with a 2m transverter. After minor modifications to the transverter, it interfaces with the rig's transverter I/O, and PTT switching was provided by a signal from the accessory socket on the back of the radio. Transverter performance on FM and SSB is excellent, limited only by the transverter itself, in terms of frequency stability and Rx sensitivity. The system beats the Standard C58 2m rig hands down, and rivalls the sensitivity of the HTs, with none of the pager intermod problems.
Conclusion:
The IC-745 is an excellent HF rig that can be picked up secondhand at a good price. The receiver is superb, with performance under poor conditions that is exceeded only by modern DSP based technology, and the transmitter is well behaved, making the radio well suited to field station use, such as WICEN exercises and portable contesting, where antenna VSWR may not be 100% perfect. The IC-745 will also suit those seeking to use transverts on VHF, UHF and micrwave bands, where the transverter interconnect facility makes connecting a transvert simple.
Overall rating:
5 out of 5.
Excellent value for money!
Copyright and Disclaimer:
This review is copyright Tony Langdon, 2001, All rights reserved Persons or organisations wishing to distribute part, all, or a derivative of this review are welcome to email me on the link below. Unauthorised distribution is prohibited.
This review is provided for the benefit of radio amateurs, and was independently written by me without the assistance of or under the direction of any other party, continuing my tradition of reviewing most new radio equipment I purchase.