Philips D2935

 

 

 This receiver uses digitally synthesised tuning from 150kHz to 30MHz and FM Band II

The shortwave broadcast bands can be selected by stepping through the complete list and specific frequencies selected by using the numbered keys on the panel but only 9 memories are provided which is far too few for this type of set. A BFO is provided for SSB reception as well as a manual RF gain control, essential for best SSB results. There is no means of selecting bandwidth which is a shame although frequency stability is good enough to use a single sideband technique along with the tunable BFO to reduce adjacent channel interference. Tuning rate is two speed governed by the spin speed of the tuning knob.

Annoyingly, FM reception is not stereo and the S-meter does not work for FM

The biggest drawback with the set is the on-off switch. It is impossible to pack the set in a suitcase without the on/off switch becoming operated. When you take the set anywhere it is therefore essential to remove the six "D" size batteries to avoid strange noises from your luggage.

With digitally tuned sets one can set the frequency directly to a short wave broadcast station and, if skip is right, you'll hear it immediately. With shortwave reception, radio signals bounce off the ionosphere and the ground or sea. Depending on the height of the particular section of the ionosphere affecting the frequency you are tuned to, you will hear stations at different distances from you. The frequency at which a section of the ionosphere affects the shortwave signal depends on a number of factors. The main one of these is the effect of the sun. The sun's radiation produces a number of reflective mirrors high above the earth's surface. Some frequencies will pass straight through some layers but others will reflect completely and bounce down towards the earth. The resulting reflected signal may travel skywards then bounce back off the ionosphere again. This process may continue until a signal has travelled all the way round the earth. Occasionally you can hear two or more signals giving an echo effect when they have bounced around the earth in different directions to both appear at your aerial. Because one may take longer to reach you, you get the echo effect.

 

 I wrote this page back in 2001, and as I pen this, some 19 years ago, I took a picture of my treasured D2935, now in a very sorry state. I also noticed I hadn't mentioned the origin of my set. Many years ago I worked for Plessey Defence Systems, and after 20 years based at the Liverpool Exchange Works factory I was moved, more than slightly unwillingly because we had not long before, moved to Swan Cottage, the birthplace of Lady Hamilton (she wasn't born with that name of course), a large detached cottage built in 1724. Anyway, a move to Christchurch, the HQ of Plessey Defence System had been instructed so we moved, all expenses paid, including a nice allowance to buy a new house. Having been there about a year I was summoned to my bosses office and informed that as I had been with Plessey for 21 years I had been given a long service award. That came as a big surprise as the Liverpool site had a £50 long service award which matured after 25 years. To my surprise I was told that I could have up to £500 but it was to be spent at Harrods in London. A trip, by first class rail for my wife and myself, was also provided, as was afternoon tea in their café. Our third child who was around 9 months old in 1986 would travel free of charge so a baby sitter would not be needed.

Generally, Harrods long service award purchases were very boring (usually including the words "lead crystal" because recipients must have thought it somehow "appropriate? My most expensive purchases were a racing bicycle and a Philips D2935 radio. Hence my use of the words "treasured D2935". It was NOT a car boot purchase!

Trawling through a Forum the other day I spotted some words of advice including "auction" so looked and to my surprise a new front panel is available from a chap in Holland. This is now on the way and hopefully, once stuck in place, will restore my treasured radio back to health. Read on..

Below is the circuit diagram... click it to see full size.

 

 Then click here see the complete Service Manual

Below... the front nicely restored. 

 

In its AM mode the receiver is a double superhet with a first IF of 2.3MHz and a second IF of 468KHz. Either its ferrite rod or whip aerial can be selected for any AM frequency (not just short waves) and it has continuous tuning from 146KHz to 29.999MHz (with no gaps) which makes it really useful for searching out interference sources. In FM mode, although it has only a single loudspeaker, it provides proper stereo into headphones.

 pending...

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