Indoor AM aerial, advice required

[stevehertz]

That was my default method for many years, and very successful too. However, I tried it last summer - having come back to the sport earlier in the year after many years away (before digital TV) - and the result was a load of digital hash - well, there were radio signals buried amongst it, but any 'gains in gain' were more than obviated by the increase in digital interference . Not surprising really as that is what is being carried down the TV aerial. I'm bemused that it works so well for you, but pleased for you too. Interesting.

[bikelectro]

All my stations are much louder, and with much less noise, it really is that good! And i can pull in distant foreign ones i couldn't get before.

[jsbhavsar]

In India, we had the aerial solution as 'long wire aerial in mesh form'. A very fine single copper wire several hundred feet long is woven in a mesh/net. Both sides are locked with plastic insulators. The plastic insulators then have springs attached.
The aerial mesh was 3 metres long or so. It was stretched tight and hung across two hooks inside the home or in the balcony. During my childhood my Dad had it inside the railway quarters we lived in India. Reception on his Philips 15RB487 tube radio was superb on all bands.

Attached some pictures; not mine but clearly show how tube radios worked in India with the indoor long wire mesh aerial.

[Ian - G4JQT]

Here's one very simple trick everyone should try if you can only install an indoor aerial and suffer lots of noise...

From the aerial socket, loop the wire around the room/window taking in as much wire as you can. Connect the other end to the earth socket. Easy as that.

You may like to insert a high-voltage 0.01uF capacitor at one of the terminals just in case there are volts where there shouldn't be any.

This is not how the aerial input circuits were designed to be used. No doubt it does all sorts of nasty things to their tuning and "Q", thus the signal strengths go down. But the noise usually goes down very much more, thus increasing the signal-to-noise ratio.

It's a trick I learned many years ago and works more than half the time in my experience.

I described this and other techniques in a BVWS Bulletin article "Installing aerials and earths - a forgotten skill?" volume 26, summer 2001.

Ian

[Synchrodyne]

Further to my earlier post #9, attached is an example of a receiver that was designed to work with a simple single-wire indoor loop. It has an input balun that I imagine is also a stepup transformer. Unfortunately I cannot find the second part of the article that likely would have included transformer winding details.

Cheers,

[jsbhavsar]

Dear Ian,

Can I use such a large loop on my National Ekco A731 8 band valve radio?

i.e
Take several meters(~30m) of a good insulated 1/18 copper wire start from aerial socket pass it across room walls and bring the other end of that wire into the earth socket?

Presently I run a several meters long 1/18 aluminium wire from aerial socket taking it to the building top (RCC buildings in India). The terrace-end of this 1/18 wire is attached to a 7 meter 1/14 thick bare copper wire. The 7m bare copper wire is hung between two egg insulators on top of the building.

Which option would you consider the best for a large valve radio with RF stage?

Thanks!

[happytiger]

What has been mentioned here is some form of loop aerial,the bigger the loop the more signal,and more turns more signal,however it must be in the vertical plane, and is directional.
One of the best is wound on a door as a flat spiral,you can then adust direction by openening or closing the door. You can connect a tuning capacitor acroos the ends to peak up the coil, it is also better to either tap or feed the receiver via a 2 turn loop,so that the antenna will not be loaded too much by the receiver input.
If you want a good loop, a large 2 turn vertical loop in the loft works fine,if you make it as a 90 degree loop it will pick up from all directions since yo cant turn it.feed the ends via coaxial to the set,and earth the braids,you dont get much noise then.

[G6Tanuki]

This weekend I plan on trying to hook up a ferrite rod to my Eddystone 840A in the hope it might be a bit less susceptible to noise (and more directional) than my 100.mumble-foot longwire.

I've got a MW ferrite-rod and suitable 500pF capacitor from a scrap radio - my plan is to use the 500pF across the tuned winding and then use the 'aerial coupling' winding of the rod in reverse to feed the balanced antenna terminals on the Eddystone.

"Daytime DX" on medium-wave can be interesting once you get past the innumerable instances of BBC Radio Borsetshire.

[Junk Box Nick]

Sadly you can cross Radio Hafren 756kHz (Newtown, Powys) off your DX list - it closed last week. It came in well here with my Tecsun loop.

Would be interesting to see how the ferrite rod performs against a tuned loop.

Originally Posted by jsbhavsar

Take several meters(~30m) of a good insulated 1/18 copper wire

Any wire will do as long as it is mechanically good enough (won't fall down!).

[jsbhavsar]

Question was pertaining to:

Is 30 meter length of outdoor wire antenna good enough?
v/s
The large indoor loop which Ian explains; just take a long wire starting from aerial socket and end that in the earth socket.

[Ian - G4JQT]

I don't know, but I see no reason why not. Thirty metres is quite a lot of antenna! With that much I'd first try using it conventionally up as high as possible away from other cables and with a good earth connection at the receiver. It might mean a lot of work, but then try looping it to the earth socket (probably via a high-voltage 0.01uF capacitor - just in case) and see which works best.

You may find that different configurations work best on LW, MW or SW. It's not suitable for VHF/FM, but if you have no other antenna for that band, you have nothing to lose in trying it!

Ian

[majoconz]

This works just fine with a small stereo receiver that has no BC band antenna - salvaged from a defunct tranny...