Old Half inch Ferrite rods

[ferrite rod man]

HI Evey one from Peter in Sheffield.
Can any one possibly help me I like to do a lot of Medium wave dx on my transistor radio and I have found over the years I have got a lot of old half inch 12.7mm in diameter ferrite rods that are between 6 and 10 long most of them are material 61 but there is a lot of difference in sensitivity and the Q on most of the 61 material rods. I can take 6 half inch rods all 61 material all 8 inch long and use them in one old transistor radio and get a totaly difarent outcome some of the rods are very sensative and have got very hi Q and have got very low loss on the mw band and pull in radio Caroline on 648KH full strength like a local station lould and clear even in the city center in Sheffield and this is in the daytime not at night but if I put in one of the other half inch rods it only gets radio Caroline very week and I am using the some radios MW coil on the rod. one thing I have notist is that the better rods are heaver than the not so good rods and on the good rods the radios MW coil peeks on all the stations right at the very end of the rod almost off the end of the rod and on bad rods I have to slide the coil on about half an inch before I got a peek on the stations and the peek is always lower on all the stations than on the better rod. My Question is dose any one have any of the better half inch 61 material ferrite rods with the HI sensitivity and HI Q on the MW band that I could buy off them as I only have got 3 of them out of the 28 half inch rods I have that are very good. Best regards from Peter.

 

[dr pepper]

If you want higher q, maybe try a stack of ferrites with the winding around the stack.
I tried this for receiving Lw time signals and it improved reception.
To tune the ant you really need an inducatnce meter so you can calc the correct cap to make resonance, or you could possible throw together a simple oscillator circuit and measure the freq.

 

[gophert]

61 material can lose Permeability and increased eddie current losses (permanent damage) if exposed to high magnetic fields, mechanical stress (including large thermal cycling) or corrosive conditions.