Sweetheart 31/1
MILITARY U.K. (different makers for same model)
- Produttore / Marca
- MILITARY U.K. (different makers for same model)
- Anno
- 1942–1944 ?
- Categoria
- Ricevitore militare
- Radiomuseum.org ID
- 71528
Clicca sulla miniatura dello schema per richiederlo come documento gratuito.
- Numero di tubi
- 3
- Principio generale
- A reazione (con rigenerazione)
- Gamme d'onda
- Onde corte (solamente OC)
- Tensioni di funzionamento
- Batterie a secco / 30/4,5 Volt
- Altoparlante
- - Per cuffie o amplificatori esterni
- Radiomuseum.org
- Modello: Sweetheart 31/1 - MILITARY U.K. different makers
- Forma
- Apparecchio portatile > 20 cm (senza la necessità di una rete)
- Dimensioni (LxAxP)
- 110 x 28 x 143 mm / 4.3 x 1.1 x 5.6 inch
- Annotazioni
-
Frequency range 6-18 mc.
This model was designed by the Norwegain engineer Willy Christian Simonsen (*1913, †2003) when he was working in the Radio Production Unit of the British War Office' Inter Services Research Bureau' (ISRB). About 50.000 units was produced (by Hale Electric Co. Ltd.?), at a price of just 8 GBP each. About 5.000 units went to the Norwegian government in exile, and were subsequently dropped over occupied Norwegian territory, intended for use by the resistance.
The Sweetheart would still work when the HT voltage dropped to 20 Volt, allowing the HT battery to last for 150 to 200 hours, whilst the LT battery (4.5 Volt) had to be replaced approx. every 50 hours.
Malcolm Haskard made a replica of this radio and & documented in HRSA Radiowaves, No, 129, July 2014. Photos and drawings have been published with permission.
- Bibliografia
- HRSA Radiowaves, No, 129, July 2014
- Autore
- Modello inviato da Ernst Rykkje. Utilizzare "Proponi modifica" per inviare ulteriori dati.
- Altri modelli
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In questo link sono elencati 146 modelli, di cui 114 con immagini e 48 con schemi.
Elenco delle radio e altri apparecchi della MILITARY U.K. (different makers for same model)
Discussioni nel forum su questo modello: MILITARY U.K.: Sweetheart 31/1
Argomenti: 3 | Articoli: 6
The Miniature Receiver OP-3 Type 30/1 is also often on the Internet incorrectly referred to as "The Sweetheart". It's a dual band (MW & SW) superhet. A Superhet is not at all like a TRF or Regenerative radio. The case is similar but knob layout different: The "Sweetheart" is a 3 valve TRF regenerative set.
Michael Watterson, 17.Dec.12
The "sweetheart" radio was developed by the Norwegian engineer Willy Christian Simonsen (1913-2003) when he was working in the 'Radio Production Unit of the British War Office'.
Following that, the "swetheart" was not manuactured by his own company "Simonsen Radio A/S" (Oslo) which he has founded in 1947.
It has to be precised where in the UK the about 50.000 units (from 1942 to 1944) was manufactured, and by whom.
Thank you very much in advance for any enlightment.
Best Regards,
GR
Georg Richter, 16.Dec.12
I have built this in a small eddystone box using 3 x AA cell for filament, 3 x 1j24b tubes instead of 1T4 and 10 x CR2032 coin cells for HT. A modern "crystal" earpiece and miniature "polycon" capacitors from transistor AM radio. The coil is miniature AM radio Ferrite Aerial coil unit with an extra winding added.
So I redrew the schematic in "Eagle" from the original. It's all the original values and wiring but the 1j18b instead of 1T4 (DF91) pin connections.
I beleive the original 30V battery is a Hearing aid type, or possibly 2 x 15V hearing aid types. I have got a wiring error so have not yet tested my replica. The external Aerial and Earth connections use TO220 transistor isolating washers to insulate terminals from the case.
Michael Watterson, 16.Dec.12