Poorest 80 meter indoor antenna

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Werthers
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Poorest 80 meter indoor antenna

Post by Werthers »

I know to some this may seem like an odd post but I want to do some experiments on what could be considered as the most poorest 80 meter antenna indoors to see if its possible to make contacts. I've not really looked into this enough, some say you can make contacts on a random length piece of tuned wire on 80 meters indoors. I would like to put that to the test... or how about the most efficient 80 meter antenna that could work on lets say a small area such as a balcony or even a window without the use of a mag loop. Any ideas?
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ch25
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Re: Poorest 80 meter indoor antenna

Post by ch25 »

Random length wire and antenna tuner, but I wouldn't bother.
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Re: Poorest 80 meter indoor antenna

Post by InTheClouds »

Imagine the receive noise :lol: it is hardly a quiet band at the best of times... then again maybe it would so inefficient it would pick up less noise. How about :

1m of wire with a load of coil turns round a piece of pipe and a 1m counterpoise ? Tap the coil where SWR works. 100W in 1W radiated at a guess.
Bandwidth won't be very good, move few kHz and you need to re-tap coil (but at least you can with a coil with tapped solder blobs).
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ch25
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Re: Poorest 80 meter indoor antenna

Post by ch25 »

I would say 100mW :)
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Re: Poorest 80 meter indoor antenna

Post by Werthers »

The Miracle Whip antenna looks like a good example of a poor antenna and from videos I've watched, they do work and contacts can be made even indoors. I don't like the price much a sub 100 pounds seems a lot considering... it can handle up to 10 watts which is another down side. A handling power of 20 watts would make it more usable. My HF QRP transceivers do roughly 14 to 20 watts. I have some under 10watts. I could build a variation of a Miracle Whip antenna for my needs.

https://www.youtube.com/watch?v=G2V1nx3 ... vinLoughin
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ch25
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Re: Poorest 80 meter indoor antenna

Post by ch25 »

http://www.g4fon.net/Musings.php
he design should be easy to duplicate, I have used no specialist parts and takes about an afternoon to put together. The cost, in the UK, was around £10 with components purchased from Maplin, and could be less if you have a well stocked junk box!
Miracle for seller pocket for sure.
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Re: Poorest 80 meter indoor antenna

Post by Werthers »

Thanks for the link. I shall see what I have.

This is another one I could try.
https://www.youtube.com/watch?v=rFnowNq ... =TheGazLab
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Re: Poorest 80 meter indoor antenna

Post by Werthers »

I might go with a Cobweb antenna for 80 meters or something along those lines. I haven't worked out yet what the dimensions of it will be and whether I have the required space for it. Space is the main issue along with getting performance from a small antenna. I will work out the dimensions and see what is possible to fit into a small space. I think I will need to experiment a bit. 80 meters is a tough one when space is limited. It may have to be a different type of antenna entirely to fit my requirements but working on the same principles of other known antenna designs. Everything I have thought of so far is either not efficient enough or points me to using a magnetic loop antenna but I want something that I don't have to tune every time I change frequency. I will need to get my thinking cap on for this one and I have all day tomorrow to work on it and see what I can come up with.
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Re: Poorest 80 meter indoor antenna

Post by dt630 »

Try 240 volt incandescent bulbs.
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Re: Poorest 80 meter indoor antenna

Post by Werthers »

I've heard a lot of people mentioning FT8 I'm more of an analog person and just want something for my 80 meter QRP transceiver. The bulb antenna looks interesting I'm surprised that one would make contacts on it. I haven't watched part two yet but saw a 750 mile contact at the end of part one so I'll watch part two in a bit.
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Re: Poorest 80 meter indoor antenna

Post by paulears »

I've got an HF radio in the office and an ATU capable of tuning the proverbial damp but of string, but 40 and 80m are totally unusable. The noise level through even a poor antenna is truly terrible. My neighbours seem to generate so much noise made worse by the stacks of railway equipment in the boxes outside.
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Re: Poorest 80 meter indoor antenna

Post by Werthers »

Yeah noise can be a problem its normally at its worse during evening times but during the day its ok. I put a 10 meter dipole in the attic and had a full scale signal of noise and was unusable so I took it down after some months, I wanted to leave it up there to see if the noise was always there and it never went away so down came the antenna and went in the livingroom no noise and made some contacts on it but its currently dismantled and put in a corner because its was bit in the way of everything.

I do ok on 40 meters but then again I use a mag loop for 40 upwards to 17 meters. Sometimes there can be noise on the bands and sometimes no noise at all. I have used lengths of tuned wire on 40 meters in the past and have been reasonably ok. I do much better on 20 meters than I do on 40. As the antennas get longer it becomes a bit more awkward when using wires for antennas due to limited space.

I think I might be ok for 80 meters in terms of noise. If 40 is usable then I don't see why 80 wouldn't be. I have been doing some calculations and drawing out many 80 meter antenna designs. I've come to the conclusion that's its possible to build one for a small space but whether it would work indoors or how well it would work indoors is another thing entirely. I have 160 foot of wire to play so I can do something in a 9 foot space.... or possibly extend it around the house if necessary somehow.... work in progress. Using slinky's could be a better option over wire. A type of delta loop maybe another option but if a delta loop is used then it would have to be a smaller version and tuning will be required for it to work on 80 meters.
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Re: Poorest 80 meter indoor antenna

Post by Werthers »

Nothing much on 80 meters at the moment. I just checked the websdr but I expect the band will be open at some point today to test my antenna. I've just kept things simple for now. I made up some coils and I will be experimenting with a shortened dipole tuned for 80 meters.

I can hear some stations coming in on 40 meters.

The 80 meter dipole is about 18 foot long with coils to make up for the shortened length and I know its horribly inefficient for 80 meters but it would be interesting to see if I can make a contact on it especially with it being indoors.
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