Apartment HF Antenna Information
I live in a second story(top floor) apartment. I have a wire abt 60ft in a sse/nnw configuration and a similar wire in an e/w configuration. With a tuner this is working quite well for my low end general coverage receiver(good noise canceling,Strong signals. I was wondering if this set up will work well when I am able to get active on HF transmitting. Being apartment bound is limiting(that goes without saying). Any one have any hints or coments?
Dennis, my first bit of advice for you, from one apartment dweller to another, is be prepared to be patient.
I've spent the last few weeks doing a lot of experimenting, mostly with cheap materials, in an attempt to assemble a well performing antenna here in my apartment. I have tried a random wire that was 100 feet long and another that was 50 feet (both were taped to the wall just below the ceiling, following whatever path I could take, i.e. around corners and down hallways, etc.), a dipole cut for 40 meters, a couple different loops, and a couple different verticals. Right now I'm in the process of refining a vertical that I had fun putting together. The reason I'm putting extra effort into that one is because I intend to make it easy to carry around.
Throughout all of my tinkering I have yet to make a QSO. I usually spend a couple hours each night calling CQ with CW. Not constant CQs, obviously, but fairly frequent. I often will take a short break between attempts and tune into a slow CW QSO (if I can find one...most folks go too fast for me!) and write down what I hear as a form of code practice. Anyway, in my opinion the poor luck with making a contact has been the most frustrating part of my situation. Hopefully you'll have better luck.
In addition to patience, don't underestimate the power of creativity! If your current wire setup doesn't work very well, don't be afraid to try something else. Here's some of the sites I found as I was reading here on QRZ and elsewhere on the internet. Maybe they will give you some helpful and inspiring info like they did me.
The last link has some excellent antenna information, and it was written in a way that is easy to understand. Definitely check that out when you have time.
Lastly, have fun! And good luck...I hope you have some success making contact despite your living situation!
That is pretty long wire. What band(s) are you trying for?
Second floor so wire is probably 20 feet in the air?
If you are weak try answering CQ's.
Be sure to listen for my beacon on 28.278.8 MHz
A lot of apartment dwellers have had good luck with Magnetic Loop antennas. You can build one for 40m-20m and another for 17m-10m that are small enough to stand in the kitchen.
This one from G4FON is portable, and I have used this one from hotel rooms with fairly decent success....which means I was able to make QSO's.
I have a magnetic loop antenna and can vouch that they work well as indoor antennas. However if I could have two 60ft wires I wouldn't need it.
You should make sure the two wires are of equal length (even if it means losing a bit off one of them) and then feed them in the center as a doublet. You should also feed them with open wire feeder. It is unlikely that the impedance is anywhere near 50 ohms on any of the amateur bands and if not the losses will be quite high if you feed them with co-ax. This could account for why you are having trouble getting people to hear you.
Feeding a balanced antenna with co-ax is also likely to result in radiation from the shield which will increase the chances of RFI/TVI.
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WD8DWH, KB8LOG and others -
When your experimenting with antennas, I can completely understand the frustration of calling CQ on a new antenna and waiting for hours, wondering if you've got a MFDL (mighty fine dummy load) or a real winner. Patience was mentioned and is a very good asset.
Something I would like to turn your attention to is http://www.WSPRnet.org
WSPR is a very weak signal beacon digital mode. WSPRnet.org is an automatic network of these beacons which report each other's signal strengths to the website. If you check out the "map" section and "database" sections of the website you'll see a LOT of reports from all around the world!
Granted, some bands have more WSPR stations than others. 40,30 and 20m all have sizable populations. 80m has a few, and the others have occasional stations.
The beauty of utilizing WSPR when testing antennas is that it's totally automatic. Let's say you tweak the antenna design one evening and want to test it. Simply hook up the rig with your laptop/computer and run WSPR. Let it run for 24 hours and come back to track the progress.
make another tweak to the antenna and repeat the process for another 24 hours.
This will give you a very good, scientifically trackable measure of how well your antenna is doing! Calling CQ is a good way, but its doesn't give you nearly as good a benchmark, and you can't readily do it while asleep or at work
Try http://www.WSPRnet.org and I think you'll be amazed at what kind of reports you get!
HQY...I would submit that running WSPR for 24 hours won't tell you as much about your antenna as it will about how well your antenna is doing during variable propagation conditions. WSPR is more about prop and less about antenna design.
Originally Posted by KE7HQY
Your point on variable propagation conditions is very valid. However on the same token, conditions on the band regionally within the first hop can be fairly static day to day and be less variable than the random DX propagations. Case in point: Being on the West Coast I can hear and am heard by stations in California daily when I have WSPR running. The same most of the time with Arizona or Colorado. This "regional" propagation works for 80-20m, depending on the time of day and antenna configuration. These "local" propagation paths aren't nearly as variable as say propagation to Argentina.
Originally Posted by KB9BVN
For example, I can compare two very different antennas by mapping S/N ratios from a California beacon with one antenna over a 24 hour period, and in the next 24 period map S/N ratios using a different antenna. Many of the bands have several beacon stations that are almost "permanent residents" in that they keep their beacons on that band for a few days. If the difference between the two antennas is minor, there will be no real discernible way to tell which antenna was better from the S/N graph. If it is a significant difference, it will show up in the S/N graph. If you are tweaking an antenna and the S/N graph shows large, statistically significant changes between two close time periods (example one day to the next), the tweak was significant!
As with all metrics, the more data points the better. If you had a week's worth of S/N graphs compared to another week, the results would be just that much better.
Last edited by KE7HQY; 04-02-2010 at 01:43 PM.