LF tube radio restoration - Page 1
Forum section: electronics / rf-microwave

author: Martin.M
author_rank: Frequent Contributor
timestamp: November 25, 2016, 07:30:36 pm
content: Telefunken E108Lw4from 10kc to 1.8mc in 6 ranges.full tube radioBFOdouble conversion superhet receiverSensitivity for 10 dB s/nrange 1+2 (LF) 0,5µVrange 3 0,45µVrange4 0,4µVrange 5+6 (500kc up to 1.8mc) 0,3µV3 antenna inputs: high, low (60 ohms) and symmetric for Loopfiltering:each band, input = 4 coilsIF1 (80 or 325kc related to the range) , both frequencys have a 6 coils filterIF2 (525kc) there are 2 crystals for selecting the bandwith in 4 steps from +-.1 to +-4.5kcabout handling of the radio: on the front plate is to read 90kgfirst picture: beginlast picture: done, the old radio is now back to life.greetingsMartin

author: Martin.M
author_rank: Frequent Contributor
timestamp: November 25, 2016, 07:31:47 pm
content: continue

author: Martin.M
author_rank: Frequent Contributor
timestamp: November 25, 2016, 07:34:26 pm
content: done.The oldie is so much heavy, we put it with 3 persons on the table..greetingsMartin

author: floobydust
author_rank: Super Contributor
timestamp: November 26, 2016, 02:38:36 am
content: What a masterpiece! Unbelievable quality and all the diecast gear-driven band-switches. Seems to be circa 1957.Reminds me of a time when cost didn't matter- "let's build something superb, a work of art" was the engineering philosophy.I'd love to DX with it. Great restoration Martin.

author: Martin.M
author_rank: Frequent Contributor
timestamp: November 26, 2016, 06:36:54 am
content: thank youthe band switches are 23 pcs. with 6 steps, driven in 2 lines by the geartrain from the knob. Addittional one pc. outside from the tuner chassis for the 12 little bulbs (6 steps x one left and one right) in the front. The most of the switches are to swapp filter coils, and related to the band the frequency of the IF1 and the second oscillator. picture Telefunken-10: this is a germanium diode ring mixer OA154Q. The tuning knob is pushed a coarse and pull a fine tuning by gear ratio. The radio have a crystal based calibrating oscillator with harmonic of 25kc for low bands, 200kc for high bands.The oldie is a great performer in DX, also it can receive the Grimeton SAQ directly. Ideal combination with a shortwave boatanchor to have the complete AM bands. The shortwave brother from Telefunken is the E104, I dont have one, but EK07 (seehttps://www.eevblog.com/forum/rf-microwave/140-lbs-of-radio-(restoration)/) from Rohde+Schwarz will do the job also perfect.I have seen on a very old picture 3 of this E108 working in the german weather headquarter, there was plates with citiy names on the radios like NY, Moskau, ....The frequency drift of the 1. oscillator is (by manual) <26Hz / 1hour, in the test with a rubidium locked counter it was below 20Hz, a warm up of a half hour is required to get that. It is full equipped with SQ tubes of long life time. There are no electrolytics, all is build with large metal paper Cs instead of them.E108Lw4 is part 2 of my project "vintage boatanchor radio tower". The next restoration is the greatful field strenght measuring receiver HFH from Rohde+Schwarz. following a second EK07. then I will stack them on a cart with rolls.greetingsMartin

author: VK5RC
author_rank: Unknown
timestamp: November 27, 2016, 09:39:10 am
content: Again lovely work, but 140lbs! You need a very strong table for that.What is the ?"Circo" spray can?Thanks for sharing.

author: Martin.M
author_rank: Frequent Contributor
timestamp: November 27, 2016, 10:20:22 am
content: this is acid free synthetic oil,it was not possible to rotate the bandswitch / gear train. This oil made it clean and easy to use.about 140lbs: that means the R+S radio.Telefunken E108Lw4 is more heavy then a EK07D.Part3 of my vintage radio will be the HFH field strenght meter receiver, the R+S with the beautiful Loops.Restoration is now running , seehttps://www.eevblog.com/forum/rf-microwave/field-strenght-meter-receiver-rs-hfh/greetingsMartin

author: TimFox
author_rank: Super Contributor
timestamp: November 27, 2016, 07:58:45 pm
content: Can you list the tube complement?

author: Martin.M
author_rank: Frequent Contributor
timestamp: November 28, 2016, 03:57:38 pm
content: E108 works with some EF805s, ECC801s, EL84 and 2 gas stabi. (SQ version)EF85, ECC81, EL84 and 2 gas stabi (following the manual, version with electrolytic C)greetingsMartin

author: Martin.M
author_rank: Frequent Contributor
timestamp: April 02, 2018, 12:15:24 pm
content: I found in the netherlands a nice E104Kw4this is the shortwave brother radio of the E108Lw4, in same case.

author: VK5RC
author_rank: Unknown
timestamp: April 10, 2018, 11:53:42 am
content: Same mass? Visit the chiropractor and reinforce the floor! Boat (Destroyer class ship) anchor envy

author: Martin.M
author_rank: Frequent Contributor
timestamp: April 10, 2018, 05:36:51 pm
content: seehttps://www.eevblog.com/forum/rf-microwave/sw-radio-restoration-telefunken-e104/

author: GerryBags
author_rank: Frequent Contributor
timestamp: April 26, 2018, 09:33:23 pm
content: Beautiful piece of engineering, beautifully restored! Thanks for sharing, Martin. The "cart" that you are planning to put this on.. WITH SOMETHING ELSE?!?.... unless it's made by Mercedes and has air suspension in mayneed a little reinforcement!for keeping alive a very attractive slice of history.