KB2GOM
Active Member
??
Any suggestions for an indoor receive-only antenna for 2-3 MHz?
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KB2GOM
Active Member
Actually -- empirically based on a power outage in our neighborhood -- RFI in the residence isn't too bad.
ka3jjz
Wiki Admin Emeritus
An active loop will work, although you wouldn't have the advantages of being able to turn it around to block a signal. Or even this - substituting a YouLoop for the receiving element might work out quite well...;.
Of course, noise and overdriving the gain will be your biggest issues....Mike
MFJ-1020C, ANTENNA, SWL INDOOR ACTIVE ANTENNA
MFJ Tunable Active Antenna MFJ invented the tunable active antenna! New technology uses a cascode FET/bipolar transistor and a gigahertz bandwidth buffer.Numerous copies have been made without success -- including most recent ones. Why? Because MFJ has made continuous improvements where others...
mfjenterprises.com
Of course, noise and overdriving the gain will be your biggest issues....Mike
prcguy
Member
Of all the antennas I've used indoors and active loop worked the best. Lowest noise and best signal.
ka3jjz
Wiki Admin Emeritus
If you have some skill in making your own loop element, this could be right up your alley....
www.w6lvp.com
or if you're interested in some portable work using a coax loop...
If you want to keep it on the cheap side to see whether it would work for you, a MLA30 plus might be in your future, and there's a pretty active FB group working some modifications on this antenna...you can find it on fleaBay
Mike
W6LVP Magnetic Loop Antenna Experimenter’s Kit | W6LVP
www.w6lvp.com
or if you're interested in some portable work using a coax loop...
If you want to keep it on the cheap side to see whether it would work for you, a MLA30 plus might be in your future, and there's a pretty active FB group working some modifications on this antenna...you can find it on fleaBay
Mike
Which one?
rupe01
Member
I have had great results with my AMLA150 active mag loop from AliExpress for around 17 bucks delivered for the kit (easy) and they say it works better than the MLA30's, although i don't own one of those. They run off a 9v battery....i use a rechargeable.
KB2GOM
Active Member
I was doing some research on preselectors, when I found the following: Improving HF Reception - The RadioReference Wiki
In that, I found the following: Another way an active preselector could be used is to use it to load a very short dipole - say not more than 1 meter (roughly 3 foot) for each leg. A number of years ago, a company called Datong marketed such an antenna (with a preamp right at the antenna feedpoint) that was popular in Europe and to some lesser extent in the Americas because it's easy to hide the antenna.
I could picture using the short dipole strung across two windows -- or a large window -- in an apartment and connected to an MFJ 1020C . I haven't done this experiment, but I have tested the 1020C, and I think it might be worth a try.
In that, I found the following: Another way an active preselector could be used is to use it to load a very short dipole - say not more than 1 meter (roughly 3 foot) for each leg. A number of years ago, a company called Datong marketed such an antenna (with a preamp right at the antenna feedpoint) that was popular in Europe and to some lesser extent in the Americas because it's easy to hide the antenna.
I could picture using the short dipole strung across two windows -- or a large window -- in an apartment and connected to an MFJ 1020C . I haven't done this experiment, but I have tested the 1020C, and I think it might be worth a try.
prcguy
Member
majoco
Stirrer
Mini-Kits HF Magnetic Active Loop Antenna
The Mini-Kits HF Magnetic Active Loop Antenna module has been designed to be easy to construct and covers 1 to 30MHz.
www.minikits.com.au
but it is a kit and you have to solder the tiny SMD components and wind the toroids. Mine works very well with a 35 yard triangular loop.
ka3jjz
Wiki Admin Emeritus
If you have the skill in handling this, and can get the parts, this might very well be the ultimate 160-90 meter HF indoor antenna...
forums.radioreference.com
Mike
Giuseppe's latest homemade ferrite rod antenna for MW/HF
See here...from the SWLing.com blog... https://swling.com/blog/2022/06/giuseppes-latest-homemade-ferrite-antenna-for-mw-and-sw/ Mike
Mike
ka3jjz
Wiki Admin Emeritus
Looks like the above has a gap in the 2-3 Mhz range, but the method of building this should be adjustable to cover that range. It's an interesting project
Mike
Mike
mikethedruid
Member
It depends to some extent on whether or not you are using a single ended or a balanced input. If single ended, you can make a suitable antenna using a Slinky. Yes, the toy. Buy one which is bare metal. Here is a link to the basic method,
I have used one before, and they do work pretty well for an indoor antenna. You can make a dipole version using 2 Slinkies. solder the center conductor of your cable to one, and the braid to the other, and strech them in opposite directions. I suggest using nylon string for the support line inside the slinky since nylon is a good insulator and is resistant to moisture.
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