crosem

History of the Australian Wireless Set No 128 (Text partly from https://www.awm.gov.au/collection/C1216608?image=1) IMG_1344.jpeg IMG_1346.jpeg IMG_1347.jpeg IMG_1349.jpeg IMG_1350.jpeg Development of the Australian Wireless Set No. 128 started in early 1944 with approval for production given in Ju...

The "25 Watts bilradiostation 25W Bl m/39" is a bit exotic transmitter/receiver of Swedish design. The first radio' s were released in 1939 and during WW2 they were produced in small quantities. As far I understand no more than about 250 "bilradiostations" (car radiostations) wer...

Hi Helvetio, Many thanks for your comment! You really put 'em in fifth gear to breadboard the USB inverter in a record time! (The proof of the pudding is in the eating) The filter characteristics are bad, but I have the same experience when I tried to miniaturize the original filter with 40 mH minia...

By coincidence I found today an EBay (“Epay”) advertisement in which an ex IDF (Israeli Defence Force) SPR-12 receiver is for sale (2 - 12 MHz). The seller mentions that this particular set was built by Tadiran and suggests that the rx was in use by IDF. The IRET-logo is not on the front, but the in...

Hi Helvezio, Tnx for your reply. Yes, the TBA-120 works very good at low frequencies! Undoubtedly the inverter will work with PRC320’ s etc. Some minor adjustments of the input attenuator may be required, that’s all. Reverse operation, from LSB to USB, works fine without any circuit alteration (test...

dr om’ s, A US company developed in the eighties(?) a dedicated telephone speechinverter IC, which is not for sale anymore. Unfortunately I can’ t remember the typenumber, but it made construction of an analog USB to LSB inverter very easy. National electronic low pass filters: National has/had a 6t...

Hi Ugo,

The TBA-120 works perfect as audio DBM, but has a bit more distortion as a dedicated modulator like the SL1640. But the TBA-120 is cheap.
BTW I just found some Plessey SL1640’ s on EBay. Price around $ 10,— Not bad at all!

Have a nice day.

73 / Cheers,

Jan, PA0CHS

This month, August 2020, the British V-Mars magazine published a state of the art version of a low frequency USB to LSB inverter intended for USB-only transceivers and receivers in order to make them suitable for LSB. The V-Mars system uses a special PIC-processor as central part of the circuit (GW7...

Some pictures of my IRET SPR-12 receiver. The batterybox is home made.

Hi Ugo, good evening, Basically it is the same receiver, but R5 was produced for the Czech army. Instead of a dedicated AF-headphone connector, the Czechs used bananaplugs. As far as I know there are technically there are hardly any differences. The DDR produced also a VHF-set component, which looke...