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Kenwood TR-751E 6v Inverter Fault

Kenwood TR-751E 6v Inverter Fault

The Kenwood TR-751E is an ageing but still fantastic 2m (144MHz) multimode transceiver.  Like all things, me included, as they get older parts start to fail.  The TR-751E I had to repair had been dropped, which meant the RF Gain / RIT dual concentric potentiometer needed straightening…the main VFO knob had already been glued.  It […]

3B/240M Tube on HF

3B/240M Tube on HF

Has anyone out there ever used a 3B/240M (CV2214) valve / tube in an HF amplifier? I came across one of these, new and boxed, amongst my collection of treasured family heirlooms…it looks like a miniature 5B/254M but isn’t.  The 3B/240M or CV2214 is a small grounded grid triode for use up to 200MHz.  It […]

SEI Crystal Filter Data

SEI Crystal Filter Data

Some years ago I acquired some superb…and originally very expensive…SEI Crystal Filters on 1.4MHz.  I knew I had a USB and LSB pair, but didn’t know which was which and had no idea about the correct termination impedance.  What I needed was SEI Crystal Filter Data…which no one had.  There have been lots of questions […]

The Horophone Story

The Horophone Story

This is the story of an old and unique Edwardian radio, the Horophone…type ‘A’ in this case…and how it came to be discovered and shared with the rest of the radio fraternity. A bit of history first… In the earliest years of the 20th century, a certain Mr. Norman Hall, set up the North Eastern Instrument […]

Kenwood TS790E CTCSS

Kenwood TS790E CTCSS

If you are the proud owner of a Kenwood TS790E, you may be rather miffed that it won’t work with modern repeaters requiring CTCSS tones; the TS790E was made in the days of 1750Hz toneburst for repeater access in the UK. Both Kenwood and their dealers will probably tell you there’s nothing that can be […]

The PW Epsom by G4AR

The PW Epsom by G4AR

As you may have gathered by now, I’m quite keen on homebrew equipment…I don’t mind whether it’s valve or solid state; I do however avoid SMD projects if I can.  One of my main interests is valve (or ‘tube’ if you live across the pond) receivers.  There are quite a few to choose from including […]

Maplin Direct Conversion Receiver

Maplin Direct Conversion Receiver

There was a time when radio hams and electronic hobbyists seemed to have more time to build things.  Maplin used to publish an excellent magazine in those days…for just 85p…that featured projects you could build, along with hints and tips for experimenters. In September 1988, Maplin introduced a really excellent Direct Conversion Receiver which many people […]

Reinventing the PS-304

Reinventing the PS-304

The Daiwa PS-304 has been with us now for at least 25 years…and most are still as reliable as ever.  A great design stands the test of time and guess what…Martin Lynch and Sons are now selling the MyDel PS-304 Mark II. Specifications: Input Voltage:  230V  50Hz +/-2Hz Output Voltage:  DC 1.5V – 15V continuous […]

Toyocom TQF-456C Crystal Filter

Toyocom TQF-456C Crystal Filter

You probably found this page as a result of a Google search for the Toyocom TQF-456C crystal filter.  I seem to collect filters like this…in case they are useful in the future 😉 It seems that an eBay seller known as ‘hifissb’, who breaks down radios and sells their modules, has a large stock of […]

 
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