Ferrite sleeve loop antenna

[murphyv310]

Hi.
Thanks Peter for your input. There is a fair amount of bleed between my local at 1035khz and the next nearest station at 1089khz so no issue with lack of treble. Increased reaction tightens this up of course and the bleed disappears. Apparently the issue is not the wire but the grade of ferrite. You live and learn.

[kalee20]

You do indeed! I'm always interested when reality doesn't tie up with simple theory, it gives an opportunity for better understanding, and from that comes an indication of what direction to move to improve things.

Your posts are always interesting, and this one is no exception!

[murphyv310]

Hi.
On a slightly different note that doesn't stray too far off topic, tomorrow afternoon after church I think I'll remove the existing MW coil from my other Rod Pentode regen radio and try and rewind it with some of the thick wire from Kalee 20 and see if there is any difference, this radio has the 15mm diameter ferrite rod and gives a good signal, I can just detect audio from my local on it as a crystal set with no external aerial and earth, any surrounding noise and its impossible, will see if the signal level rises with the new wire.

[kalee20]

Again, I'll be interested!

If the losses are dominated by the crystal detector and headphone load, then almost no difference would be expected. But if the original wire contributed significant losses, then you will see a difference.

A bigger rod will also help, not because it raises the Q (in fact it might even drop it very slightly), but because it'll give greater signal pick-up.

[murphyv310]

Hi.
I tried Peters wire and yes there was a small increase in signal levels, but I did get a much bigger increase with other wire.
Initially my FSLA used three sections of litz twisted together and this was wound round the rod, I used 40 turns, this tunes from 530kHz to 1.8MHz with the existing tuning cap. At the low end there is a 100% lift and at 1431khz around 60% increase in level it now is producing more output than the FSLA according to levels measured on the scope. Its slightly untidy but works brilliant.

[murphyv310]

Hi.
This afternoon I decided to try less turns of wire to try the FSLA on shortwaves. The Ferrite rods I bought could well be suited for higher frequencies so after reducing the turns to twenty around the rods it would tune from around 2Mhz up to 6.5Mhz. Results were OK ish up to around 3.5Mhz then a rapid fall off. I was still able to get it to oscillate with the added Q multiplier but it was extremely insensitive. Again I believe these Ferrite rods are the problem.
I'm not throwing any further cash on this project now and I think it's time to put it to bed.
I'm still open to suggestions but will have to limit this to what I have already got in relation to parts.

The only thing I might try is making this with a small frame aerial and give it a try.

[murphyv310]

Hi.
I've rewound the FSLA with 7 turns of the tripled up litz I used early on. I'm listening to an amateur radio net on 3709Khz with the FSLA and the D-808 fed from it. The signals are romping in. It tunes from 1800Khz to 6000Khz and works very well. I was listening to Shannon Volmet earlier with great results.
I now agree that the ferrites I have are good up to at least 6000Khz