464
Item nr.
Check antenna operation.
Production | The Netherlands, 2017. |
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Bands | AM, roughly 150 - 3000kHz. |
Semi- conductors | TA7642. |
Cabinet | Plastic profile. |
Power | Batt 1.5V (AA, soldered). |
Documents | Schema. |
The monitor connects to a loop antenna, which is basically a tuning tank, so it need not contain a tuning circuit. Also, I found a 700 Ohm earpiece in my junk, eliminating the need for R1 in the classical TA7642 basic circuit, altogether now reduced to the IC plus three electric components. The AA battery can be soldered, providing a reliable long term connection.
Obtained | 6/2017 from Home built. |
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Condition | 9. |
Disposed | Storage (inquire if interested to buy). |
At first I considered the idea of building the entire unit (with a watch battery) in a coax male plug. But studying the size of the inside of this plug made me abandon this plan. I built the monitor on June 26, 2017, and immediately received five MW stations using my TelRaam antenna: 621kHz Wavre (Belgium, French), 693 (BBC5), 1008 (GrootNieuws), 1053 (TalkSport, English), 1584 (R.Pardijs). Especially the English station on 1053 was quite a surprise to me, as its frequency is quite close to GNR (1008). I found out that the null in the directionality of my antenna is not equally sharp on both sides. If I try to null GNR on one side, it does not disappear sufficiently to hear Talk, but turning the antenna over 180 degrees completely silences GNR and opens Talk.