Modern Communications Receivers & Transceivers

 Kenwood R-2000

 

 As you can see the above receiver is a Kenwood Model R-2000 which due to the vagaries of trade names is sold under more than one brand name such as Trio. This all-band (100KHz to 30MHz) example includes an optional extra VHF front end which extends reception to the airband.

See the operating manual for the R2000

 

Icom IC-R7000

 Above is a more expensive receiver, again Japanese, an ICOM IC-R7000. This set is designed for reception of higher frequencies than the Kenwood (25 to 2000MHz) and is very useful for checking 433MHz radio keyfobs, a job I did regularly for our local garage.

See the operating manual for the R7000

 

Heathkit SS-9000 

 Above is a fine example of a Heathkit SS-9000 amateur band transceiver, purchased by the late G3AQY and his wife the late G4GOJ. This rig which dates from the 1980s was said to be impossible for home construction due to its complexity and only around 350 were made in the Heathkit factory so is pretty rare. The matching power supply, PS-9000 is shown below. To see an example of G3AQYs home-brew click the above picture.

 

 

Heathkit HW-5400 

 Above another Heathkit transceiver. This was also made from a kit of parts which were secreted in my suitcase on returning from a business trip to Dallas, Texas in 1985. Building this rig was made more complicated than it should have been because the parts had been separated from the sets put together in a clever way to aid construction. Nowadays an X-Ray scan of the suitcase would probably result in an alert and empty the Heathrow arrivals hall.

 

 

 I was away on business for Plessey in 1985. We were bidding with Rockwell for a new US Army Communications System and staying at the Harvey House Hotel in Plano Texas. It was my second visit and I'd planned to buy a Heathkit HW5400. Rather than drive into Dallas I rang Heathkit and spoke to the manager John Mitchell who agreed for 10 dollars to deliver the transceiver kit to my hotel. I paid something like $500 which was about 50% of the UK price.
 I looked up John the other day and sadly found he'd died in 2002. The worrying thing is he was born only a few months before me.

 

  Below this is a second Heathkit having a few extra features including a matching power supply, that was bought as a kit by G3AQY a little later than mine. The matching power supply, HWA-5400-1 is shown below the transceiver.

 

 

 

Trio TS-120S 

Below is a commercially built amateur radio HF transceiver from Japan, the Trio TS-120S. Although looking fairly similar to the Heathkit models, this transceiver has the edge in mechanical design, general appearance and operating experience. I think it's fairly true to say that the SS-9000 was Heathkit's last ditch attempt to woo the amateur radio market before it went out of business in 1992. This left Japanese manufacturers the major supplier of amateur radio equipment across the world and enabled them to charge extremely high prices, which they still do to this day... I must say that although these rigs look very attractive mechanically, once you look inside the construction leaves a lot to be desired especially in terms of maintainability.

 

 

 

 

 This compact Trio ATU arrived with the companion Transceiver TS-120S above.

 

Basically, the ATU can match an aerial having an impedance of between 20 and 300 ohms at the operating frequency of a transmitter having an output of 50 ohms. This is done by using two controls, R Tune and X Tune whilst checking the SWR to make this as close to optimum as possible..

 

 

 

  

Left is the schematic for the AT-120 and below is a simplified circuit diagram showing a Pi network having a switchable input capacitor/coil and a variable output capacitor together with a variable series capacitor.

 

The bandswitch has three sections. The first selects a set of fixed capacitors for the selected amateur band. The second selects the appropriate coil tapping, and the third is used only for either straight-through operation or tuning.

The circuit shows the band switch in the straight-through position and, as the switch turns clockwise, selects the 80/40/20/15 and 10m amateur bands.

 

 

Yaesu FT-480R

I used this 2 metre transceiver for many years. It was hugely expensive and let me down once, shortly after purchase, but was repaired successfully by the supplier in Louth. The PA module had failed and was probably a stock fault due to a poor component as it didn't fail again over the next 40 years. The rig came with a mounting bracket so it could be used in one's car. I had a five-eighths whip and later a seven-eighths whip although this was rather large and objected to being driven around multi-storey car parks when it used to clonk on fluorescent lights.

 

 

Heathkit Linear Amplifier- HA14

click on picture to read construction & operating instructions

This SSB linear was purchased by my father in law, the late G3AQY, and has a matching power supply, the HP-24 (below). It was used frequently and found to run pretty warm so he made a fan unit on which it stood. It's rated at 1000 Watts PEP and uses a pair of 572B triodes (click to read the spec..a development of the 811A)

1000 watts PEP is a way of expressing 700 watts average power or 28.45dBW. In the UK the radio amateur transmitting license has for many years specified the maximum power permitted. Originally we were allowed to use 150 watts DC input to the transmitting valve (or valves if used in parallel or push pull) with an output no more than 100 watts. In other words the efficiency of the valve and its output circuitry defined the maximum power fed to the aerial. Now the license includes the term 26dBW PEP. This is taken to be 400 watts PEP and equates to 100 watts of carrier power. In other words... nothing has changed, just terminology. Of course.. if you run this Heathkit SSB amplifier at its maximum rated output you will be breaking the terms of your license.. here in the UK. The answer is whisper into the microphone.. use your normal voice you will be breaking the law.

 

 

 

 

Heathkit 2m FM Transceiver HW-2036A

Another ex-G3AQY constructed kit; an early synthesised 2 metre transceiver using a rotary switch for channel selection, set below to 145.500MHz. Without the mains power supply it could be operated mobile using a 12 volt power input.

 

 Read an advertisement from 1978 for the HW-2036A

 

 

Toyo Dummy Load

Clearly marked and neatly covering most of the popular amateur bands and rated at the legal UK maximum power of 100Watts

 

 

Heathkit SWR Bridge HM-102

click the picture to read the assembly & operating instructions

As you can see below, this SWR bridge also performs as a power meter in two ranges.. up to 200Watts and 2KW

 

 

Heathkit SWR Bridge HM-2102

click the picture to read the assembly & operating instructions

This SWR bridge using much the same was designed for the 2-meter band also performs as a power meter in two ranges.. up to 25Watts and 250Watts

 

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