====== Test equipment FOX / SE-100 ======
**FOX test equipment**; manufactured by [[Autophon|Autophon AG, Solothurn]].

For calibration work on the [[SE-100|Funkgerät FOX]] or [[SE-100]], the Swiss designation of the American **BC-611**, Autophon developed a test set for the channel alignment of the [[SE-100]], which is necessary after every change of operating channel.

{{:images:t-100-autophon-testgeraet-fox.jpg?direct&600|}}

===== Technical data =====
  * [[Principle]]: Voltmeter for heaters / plate batteries, tube voltmeter, RF oscillator

==== Power supply ====
  * [[Batteries]]: Heaters battery [[BA37]] 1.5 V; plate battery [[BA38]] 103.5 V

==== Dimensions ====
  * mm, kg

==== Accessories ====

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{{:images:t-100-autophon-testgeraet-fox-front.jpg?direct&600|}}
===== Operation =====
The **FOX test set** developed by [[Autophon]] to work on the **[[SE-100|FOX / SE-100]]** handy-talky radio can be used for measurements of the operating voltages and channel alignment.

The [[SE-100|FOX / SE-100]] (model 48, [[Autophon]] variant or model 44, original U.S. BC-611) is a quite unique set keeping in mind that only one crystal controlled channel is available.

To change the operating frequency, the transmitting crystal (TRANS), the receiving crystal (REC), the plate coil - the so-called tank coil - and the antenna coil must be replaced on the chassis removed from the case. In the original American BC-611, the four items per frequency channel (two crystals and two coils) are stored in the BOX [[BX-49]] accessory box.

As the set is slightly detuned when it is inserted into the cabinet due to it's capacitance, the chassis of the [[SE-100]] removed from its cabinet must be fitted with the set of four for the new operating frequency. Then tha chassis is inserted into a test cabinet, which has colour-coded access points for the adjustments. The test cabinet and the meter are used to align the set to the new frequency in accordance with {{ :manuals:se-100-das-funkgeraet-se-100-regl-65-5d-1954.pdf |Reglement 65.5d}}.

Furthermore, the FOX test set meter can be used to control the cylindrical [[BA37|heater]] (1.5 V) and rectangular [[BA38|plate battery BA38]] (103,5 V).

The FOX / SE-100 test set consists of a metal case with a carrying handle, in which the two batteries of 1.5 and 103.5 V can be inserted into a battery compartment on the side. At the bottom right, the operating crystal for the oscillator ([[3S4]]) can be inserted into a crystal socket, which is installed in a compartment with a sliding cover; the oscillator of the test set can be modulated with 1000 Hz ([[1T4]]).

===== Technical principle =====
HF oscillator ([[3S4]]), crystal-controlled; AF modulation tone 1000 Hz ([[1T4]]).

==== Tube assembly ====
V1 ([[3S4]], HF oscillator); V2 ([[1T4]], tone generator).

==== Development ====
The FOX test set has been developed to control and to do channel alignment for the [[FOX]] / BC-611 sets of which the Swiss army had bought a lot from U.S. surplus and had a licence production of another few thousand sets at [[Autophon]].

==== Deployment ====

{{gallery>:images?t-100*.jpg&0&80x80&lightbox&showtitle&titlesort}}

===== Technical documentation =====
  *{{ :manuals:se-100-das-funkgeraet-se-100-regl-65-5d-1954.pdf |Das Funkgerät SE-100, Regl. 65.5d, 1954}}

==== Further information ====
  * [[http://armyradio.ch/radio-d/t-100.htm|Test equipment FOX on www.armyradio.ch]]