The "IEC Dummy Antenna" ? - UK Vintage Radio Repair and Restoration Discussion Forum

Bazz4CQJ · 26th Dec 2013, 4:53 pm

The above device seems exist in few other places than the alignment procedure for Realistic's DX-160 receiver. That is an early 1970's 5 band radio with a J-FET front end. An assembled version of the antenna can be seen here http://www.freeinfostuff.com/DX160/DX-160_Alignment.htm. It consists of a few filtering (?) components which sit in the RF live line between the sig gen and the Rx.

Could anyone explain what the use of this unit achieves?

B

26th Dec 2013, 5:25 pm

It simulates the average 'long wire', not perfect but at least a comparison point.

Bazz4CQJ · 27th Dec 2013, 9:27 am

Thanks for that info Merlin. I can see what the objective is, but I've never seen that device or anything similar used previously. But for the sake of 5 components (now wired up inside a 1960's tobacco tin

, I'll comply with Realistic's recommendation.

B

G6Tanuki · 27th Dec 2013, 10:18 am

It's quite common to have something smilar in the alignment instructions for valve receivers designed to use wire antennas: often simply a 400-ohm resistor wired in series with the output of the sig-gen.

[400 ohms was seemingly some sort of traditional 'assumed impedance' for an end-fed length of wire on the MW/LW broadcast bands.]

26th Dec 2013, 4:53 pm	#1
Bazz4CQJ Dekatron Join Date: Apr 2009 Location: Oxfordshire, UK. Posts: 4,935	The "IEC Dummy Antenna" ? The above device seems exist in few other places than the alignment procedure for Realistic's DX-160 receiver. That is an early 1970's 5 band radio with a J-FET front end. An assembled version of the antenna can be seen here http://www.freeinfostuff.com/DX160/DX-160_Alignment.htm. It consists of a few filtering (?) components which sit in the RF live line between the sig gen and the Rx. Could anyone explain what the use of this unit achieves? B

26th Dec 2013, 5:25 pm	#2
Guest Guest Posts: n/a	Re: The "IEC Dummy Antenna" ? It simulates the average 'long wire', not perfect but at least a comparison point.

27th Dec 2013, 9:27 am	#3
Bazz4CQJ Dekatron Join Date: Apr 2009 Location: Oxfordshire, UK. Posts: 4,935	Re: The "IEC Dummy Antenna" ? Thanks for that info Merlin. I can see what the objective is, but I've never seen that device or anything similar used previously. But for the sake of 5 components (now wired up inside a 1960's tobacco tin , I'll comply with Realistic's recommendation. B

27th Dec 2013, 10:18 am	#4
G6Tanuki Dekatron Join Date: Apr 2012 Location: Wiltshire, UK. Posts: 14,007	Re: The "IEC Dummy Antenna" ? It's quite common to have something smilar in the alignment instructions for valve receivers designed to use wire antennas: often simply a 400-ohm resistor wired in series with the output of the sig-gen. [400 ohms was seemingly some sort of traditional 'assumed impedance' for an end-fed length of wire on the MW/LW broadcast bands.]