In the 1970s, Yaesu began moving more and more toward sold state designs, abandoning vacuum tubes. In the transitional phase, many models were mixed or hybrid types that used vacuum tubes only in the output stage. This was the design approach commonly used until less expensive high power transistors became available by the late 1970s. After that date, all models quickly switched to entirely semiconductor based designs like the ones shown on this page. There were great advantages to the use of transistors rather than vacuum tubes: they produced far less heat, had reduced maintenance requirements, and needed no high voltages. Because of this, most of the later models did not incorporate power supplies, but depended on an external source of 12 Volts (actually 13.8)  at a peak of about 25 Amperes. Such radios could easily be operated from batteries in automobiles, greatly simplifying mobile installations.

It seems to me that the FT-107 culminated the design concept begun with the FT-101 series. This radio physically resembles ones in that series and somewhat resembles the FT-901 and FT-102 models. The circuits are likewise somewhat similar also, except of course for the output stages which in the FT-107 were entirely solid state. The FT-107 was novel in another respect: it could be obtained in an off-white version, quite unlike the dark cabinets used in most other radios. For those that preferred, a dull gray version was also marketed. I purchased the radio shown here because I found the light colored cabinet attractive. The radio acquired a certain cachet because of the color, and I have seen it referred to as the "white elephant."

Another radio of about the same era, was the FT-7 and the FT-7B. These transceivers were intended from the beginning primarily as mobile radios, having mounting attachment thumbscrews on the side of their cases. The FT-7 was capable of 10 Watts output while the FT-7B could provide 50W and had a few other minor refinements. This particular model was diminutive in comparison to other equipment on the market at the time and can be considered a forerunner of the IC-706 and TS-50 mobile/portable radios of a decade later. These were simple radios having none of the upscale features of the larger transceivers, yet they remain much loved by their owners. The FT-7B I obtained was dirty but otherwise in fine condition and despite the years, its alignment was nearly spot on. As an addition, I built  the digital display seen here from a kit which I purchased on eBay.

   
Perhaps the Yaesu transceiver that presented the biggest difficulty in restoration was the FT-ONE. This radio was introduced in 1981 as the flagship model in Yaesu's lineup. It remained on the market for five years but never became a best seller because it was priced at just under $3,000, a jaw-dropping figure at the time. It did offer for the first time some nice features--tuning by frequency synthesis, general coverage from 150 kHz to 30 MHz, internal memories, a wide range of filters (seen above), and bandpass width and adjustment controls. There is no band switch on this radio; instead, frequencies are selected by a combination of a keypad and a rotary control used to select one megahertz band segments. Unfortunately, this in the long term became its biggest drawback because keeping oscillators in the synthesizer aligned and on frequency proved to be a formidable task. Most owners of these radios have found that their units eventually had problems in frequency calibration and alignment. When I received the unit seen here, it could not be aligned and would not receive SSB properly. In the end, I had to modify the local oscillator board seen above in order to achieve acceptable results. Frequency readout accuracy was another problem and required some tricks to remedy. In case you are interested, I may add another page of explanation about how I resolved these issues. Check back later.

Another radio that I picked up for a modest price at a hamfest about in the early 2000s was the FT-900CAT. After restoration, I liked the radio so much it became my daily driver for several years. The letter C in the suffix refers to a Collins mechanical filter. The  transceiver had an internal antenna tuner, which refers to the letters AT. The tuner is highly useful if you usually operate barefoot or with one of the older amplifiers.  I was originally attracted to this rig by the availability of these options and by its small size. For a few years, it was the radio of choice for DXpeditions because of these features. This model was designed to be used as a base station or mobile. If used as mobile, it was possible to detach the control panel from the main unit as shown here, allowing the control panel to be placed near the driver while the larger and heavier main body could be placed wherever convenient and connected by means of a separation cable.

 
I acquired the FT-1000dx Mark V field because I had heard so much about the FT-1000 series; for a few years in the early 2000s it seemed to be the preferred transceiver among top-flight contest and DX operators. There were actually quite a few variants of the FT-1000 model and there were wide differences among them. My radio, the Mark V version, came at the end of the FT-1000 series production. There were, however, two versions of the Mark V model, one offering 200 Watts output but with an external power supply, and the other the "field" model providing 100 Watts output and having an internal power supply. These radios were extremely capable transceivers incorporating every imaginable feature integrated in their design. Provisions were made to accommodate many filter choices, and I was able to complete my set of filters as seen above through eBay purchases.

 

The final two radios I include here are current models.The FTdx10 came to me via trades and sales. I wanted a more up-to-date transceiver at my workbench operating position. I considered others but was discouraged by the failure to integrate a spectrum display in many.I feel in this era a modern radio without a spectrum display is just not complete. I know some operators don't consider them very useful, but as noted above I rely heavily on these diplays to monitor band conditions. My choice was also limited by the restricted space available. Finally, the FT-891 was purchased as a full-power portable radio that I might take on my overseas trips. When traveling abroad, especially for extended periods of time, weight and size become major considerations, and this radio is the smallest of all compact full-power transceivers.

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