Horizontal long wire MW aerial.

[pwdrive]

Skin effect happens at all frequncies. Including 50hz power lines. The effect is greater at higher frequncies. A thick cable isn't an efficient way tget low resistance at rf.  Several thinner cables insulated from each other should work better.  Think of litz wire on a bigger scale.

Yes I know that, I was commenting on the difference between the two types of cable that Mike was on about.

EDIT: Sorry....post crossed

Lawrence.

[Murphyv310]

Yes Lawrence, one major reason I use an isolated RF transformer. And another reason not to tie the earths together.

[Crackle]

I carried out some more tests with the new earth. Using my bench supply on an Isolating transformer, at 10v DC there was 1A current. giving a resistance of 10 ohms between the mains CH radiator and the new earth.
Being as the CH system is connected to the main house earth point, as is the mains water pipe, dose 10 ohms seem about right and suitable as an RF earth.

thanks
Mike

[Murphyv310]

That is a very good result for a home made single earth rod.
The effectiveness will vary on the soil and of course how wet it is, to be fair though I find it difficult to tell on my sets any real change between dry and wet weather. I have thought in the past there is less noise during a wet spell which is most of the time, I think it's all in the mind.

[Crackle]

Today I finished my new mast located at the end of the garden, and hoisted the new long wire aerial. In the end to save on the suspended weight I used bare 14 gauge solid copper wire (about 1.7mm diameter) for the aerial and drop.
It is suspended from a rope around the base of the chimney to the top of a wooden mast about 6m high fitted to my brick shed, very similar to my original drawing on post #22 http://golbornevintageradio.co.uk/forum/...p?tid=6522&pid=70874#pid70874
I am happy to say that early tests seem to indicate it is much better than my old aerial.
The new RF earth also seems to make more of a difference with this new higher wire as well, I have not tried it with any matching unit as yet.

Mike

[Murphyv310]

Good stuff Mike.
Glad it's now working well, I'm sure you'll be able to fine tune it for even better performance.

[Crackle]

I was testing the aerial and earth with a HMV 1107 last night, I also connected up the Global AT2000 coupler.
The new RF earth does make a distinct improvement to the signal, but not quite as much as the earth from the CH radiator, (mains earth).
The ATU peaks up nicely on the HF end of MW and even better on the SW band, making a big difference to the quality and strength of the signal when compared to if it is switched to "through".
The new setup all works well with a valve radio designed for a long wire aerial, but although the new aerial does boost the signal with a transistor radio with AM aerial sockets, (Philips D2935 https://www.radiomuseum.org/r/philips_d_2935_d2935.html ) the ATU seems to have little effect.
Oddly, the HMV 1107 struggles to receive Gold on 1548kHz even with the new aerial, yet my Hacker RP25A has no problem on just its ferrite rod.
I need to test a few of my KB radios, but they are all downstairs at the moment, and I pulled my back a little raising the new mast up, so that will waite a while till it feels better.
So far in my tests the wanted signals are swamping any unwanted interference, but then I still have the scart to RF converter, which was the main cause of interference, unplugged.
Mike