help with adding an external antenna jack for AM reception

[durk80]

I have a Sony ICF9740W table top radio. The AM reception is decent at night time; however, I would like to add in a jack to plug in an antenna like this:

I've packed the ferrite rods in the pvc pipe, wrapped the coils around the pipe, and attached the variable capacitor to the primary coil. I haven't laid on the coupling coil yet. Within the radio, there are four thin leads I can see from the built in ferrite antenna that go to the circuit board. I'm a little lost with where to solder in some shielded wire to add an external antenna.

 

[durk80]

The guts:

 

[heyraz]

Looks interesting.
If I was designing an antenna, I'd reach out to a Ham radio guy or join a Ham forum.

 

[durk80]

Looks interesting.
If I was designing an antenna, I'd reach out to a Ham radio guy or join a Ham forum.

Thanks for the info, heyraz. I've debated putting it on a ham forum since it is just a regular AM/FM receiving set. Do you happen to know of a good ham radio forum that you think could help me understand where to attach the connections?https://ia804500.us.archive.org/5/items/manual_ICF9740W_SM_SONY_EN/ICF9740W_SM_SONY_EN_text.pdf

In the service manual on page six, I'm wondering whether I should connect it to the oscillator or the other portion of the coil down by the tail.

 

[heyraz]

Sorry, I'm not a Ham operator and I have no knowledge or recommendations.
I have some friends that are operators and was impressed and amazed by their knowledge.

 

[audiodummy]

if your antenna has high enough Q-factor (or preamplified), probably can just capacitively or inductively couple into the circuit by dangling a wire near the loopstick, parallel to the existing windings. Trouble being that adding stuff to the circuit affects / detunes the circuit if it wasn't designed for an external antenna from the start.

 

[ng0k]

I'm not expert but normally they are coupled with some sort of loop. You might try direct coupling by looping turns of insulated wire around the internal bar antenna then those leads would be connected to your new antenna feedline. Good luck experimenting! I saw some options here:

http://peditio.net/utility/pdf/Antenna_Couplers.pdf

 

[knifeswitch]

There are some radio buffs at the sister site videokarma.org

 

[cademan]

Just connect it to where the original ferrite wire is connected on the circuit board and if you are wondering which connection that is, just touch your finger to each one and attach it to whichever is loudest and brings in the station the clearest.

You won't get shocked or feel anything as long as you stay away from the 120VAC input and power switch but I assume that this is a battery powered radio which is even safer.