Antennas for postage-stamp sized lots

ka3jjz

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If you live in an urban environment then trying to put up a good full sized antenna - even a PAR- could present some challenges. Adding to the issue are HOAs, which makes things even more difficult. If you can't use a vertical (stands out like a sore thumb) and don't want an active loop, what can you do? My brother lives on such a lot. It's so small my 2 year old nephew can easily throw a ball across it.

Here are just a few ideas I've come across....

Active whips (E Field antennas) - I'm no fan of these kinds of antennas, of which the PA0RDT is probably one of the best known. I have also read that a good deal of work is needed to tame them - it's not a simply slap it up there and it works. Here is an interesting article from SWLing.com on the subject...


Hidden Wire Loops - These are invisible (or nearly so) to a HOA or even a neighbor...some of these come from the SWLing.com blog...





If you sit somewhat away from the street - and have understanding neighbors - these wire antennas just might fill the bill




You will likely have some bands that will work better than others, but these might be a better bet than just 'throwing a wire out there' as I have seen a few folks here say.. Sometimes a little science is helpful, too....Mike
 

vagrant

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This is a great thread. By pulling from the RR Wiki links to address the small lot, HOA concerns, or at times the ultimate keep the spouse happy by not having "those ugly antennas" everywhere, you will help many who may never look at the Wiki. I have made and further tested several of these antenna types. It was indeed educational. My favorite of the above is the End Fed Half Wave, as long as you can get it up into the air. The wire can be quite thin and difficult to see which is a good thing in this context. Even if one had to run it on top of the fence line, it would help. Additionally, two of these running perpendicular to each other and a switch inside the shack can improve things for directivity.

Taking it further...

For those that try one of these antennas yet still have, or already have too much noise/RFI, you may want to look at the RR Wiki for loop antennas. The small versions of these antennas allow one to turn it and typically reduce/null the noise/RFI to some degree or entirely. These can be made or purchased such as the RTL-SDR.com version of the Youloop portable antenna.

Additionally, an AM broadcast filter may be very helpful. These may be a notch filter for the entire AM broadcast band, or in the form of a High Pass Filter that allows signals above the AM Band to pass. I have an AM filter made by Dale Par and it works great. I also have an RTL-SDR AM High Pass Filter (HPF) which costs five times less and also performs very well. There are of course differences between the two, but for less than $20 to test and see if it helps, it is worth it.

Oh, I almost forgot. I am a fan of passive antennas and I should note that a preselector can be a very helpful addition to one's setup.

Update: I did forget about possibly adding an RF choke as well to the feedpoint. I added a commercial version and it dropped my noise floor by two S units which is significant. Still, that was on one particular antenna and should not be assumed that it will do the same on other antenna setups.

( I added the RTL-SDR brand items to the appropriate areas of the Wiki )
 
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ka3jjz

Wiki Admin Emeritus
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Messages
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Location
Bowie, Md.
Yes, all that might be helpful in an urban setting, but I will add one caveat - I would recommend a passive preselector, not an active one in such environments. The difference is that a passive preselector doesn't have any stages to add gain - something we definitely don't want to do in an area where there might already be too much RF floating around. These are quite useful for SDRs with little or no front end filtering such as the RTL-SDR v3 or the Funcube, just to name two. We have a few examples here...


No one solution would fit all. This is an area where experimentation in your local RF environs is going to be key. Just be aware that such solutions exist- be ready to do some homework if you wish to tweak your installation further

Mike
 
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