Call Search
     

New to Ham Radio?
My Profile

Community
Articles
Forums
News
Reviews
Friends Remembered
Strays
Survey Question

Operating
Contesting
DX Cluster Spots
Propagation

Resources
Calendar
Classifieds
Ham Exams
Ham Links
List Archives
News Articles
Product Reviews
QSL Managers

Site Info
eHam Help (FAQ)
Support the site
The eHam Team
Advertising Info
Vision Statement
About eHam.net

   Home   Help Search  
Pages: [1] 2 Next   Go Down
  Print  
Author Topic: 15th floor apartment and QRP  (Read 7166 times)
KA2ZEY
Member

Posts: 78




Ignore
« on: December 10, 2012, 11:32:48 AM »

Hey All,
I am moving to a 15th floor apartment (urban) with wide open views to the northwest and East. Given the height, I am considering a new Ham setup for QRP. We will have a balcony where I could operate from. I'll probably get a ft-817 and I'm looking at various antenna options. I know that something like the Miracle Whip is very inefficient at ground level but being on the 15th floor, would it improve the performance greatly? I'm also looking at the Alex Loop but it's pretty pricey. There's also the Hamantenna CN35.

There is no roof access and of course, full length or even 1/2 length dipoles are out of the question.

Any thoughts?
Logged
W1JKA
Member

Posts: 1716




Ignore
« Reply #1 on: December 10, 2012, 12:03:14 PM »

  How many floors and or balconies directly above yours?
Logged
KA2ZEY
Member

Posts: 78




Ignore
« Reply #2 on: December 10, 2012, 12:04:38 PM »

Just one more floor and a balcony right above.
Logged
KQ0C
Member

Posts: 25




Ignore
« Reply #3 on: December 10, 2012, 12:30:24 PM »

Lots of options but probably the best performance would be to dangle an end fed half wave down from a support that takes it away from your balcony. The Par EndFedz would work. All your neighbors would see is a thin wire hanging down... perhaps slightly weighted.

A second option is a short vertical mounted to your balcony railing, and perhaps slanted slightly to the outside. Either a ham stick , Buddi Stick, or MP-1. Use a tuned radial.

KQ0C
Logged
W1JKA
Member

Posts: 1716




Ignore
« Reply #4 on: December 10, 2012, 01:23:50 PM »

    Ditto above,also if your balcony is extruded out rather than inside and have neighboring balconies I have seen a few inverted l set ups between and dropped down from them.These hams had friendly neighbors.
Logged
VE7TIT
Member

Posts: 62




Ignore
« Reply #5 on: December 10, 2012, 01:28:13 PM »

I think a small loop would be your best choice. If cost is an issue, you can homebrew an adequate one from 10' of copper pipe and a small, inexpensive air-variable capacitor--small loops only get difficult/expensive when you start talking QRO. There are tons of homebrew examples on the web. This calculator works the design equations from the ARRL Antenna Book for you: http://www.66pacific.com/calculators/small_tx_loop_calc.aspx

Here's a page from a guy in a similar situation to yours:
http://www.qrz.com/db/N8HM
Logged
STAYVERTICAL
Member

Posts: 873




Ignore
« Reply #6 on: December 10, 2012, 01:37:49 PM »

I guess you have a few things to consider:

1. R.F. noise from adjacent apartments.
2. Possible RFI into adjacent apartments.
3. Antenna efficiency.
4. Building structure limitations.

1. R.F. noise pickup is fixed, and can be managed by noise cancellation techniques, or beam patterning.

2. Since you are using QRP, RFI is unlikely to be an issue, and can be safely ignored.

3. Antenna efficiency is a function of antenna length in many cases, or construction quality in the case of magloops.
   Magloops will work well if properly constructed, but are not exactly easy to pack away in most cases.
   I am not a fan of coax braid type magloops and would go to copper tube ones if you were to go in that direction.
  
   Antenna problems basically split into two issues - efficiency and matching.
   Matching the antenna impedance to 50 ohm feedline takes up much of the average hams time.
   This can be solved by using a remote antenna tuner, which will allow you to experiment with diverse antenna solutions easily.
   Once you have a remote ATU, you can then try small verticals (use top loading if possible), random length wires or any other
   solution you wish to try.

   For example, you could use two fishing rods, one at each end of your balcony, and string a loop of wire between them.
   Feed it with a remote ATU directly at the feedpoint, and you will have a pretty good, and probably quiet antenna.
   Since you are so high, it will be like an antenna high in the air.
   The re-bar in the balcony will probably have some effect, but it will not be great in my opinion.
   This is the flexibility of a remote atu.

   If I were in your position this is what I would do, ensuring maximum flexibility in antenna options with the least matching difficulty.
   Even coax type autotuners can be used to feed an antenna directly if you protect them from the elements.

4. Building structure limitations are those only you know regarding what is acceptable to be mounted and so forth.

I have worked some QRP japanese hams who live in apartments without balconies.
They operate at night and reel out a random length wire on the end fishing rod sticking out a window - so it can be done.

Your height is the ace in your deck, and I am betting you will get good results with a simple setup because of the altitude.

Good luck,

73 - Rob

« Last Edit: December 10, 2012, 01:48:48 PM by STAYVERTICAL » Logged
W9GB
Member

Posts: 2623




Ignore
« Reply #7 on: December 10, 2012, 06:57:14 PM »

Quote
Hey All,
I am moving to a 15th floor apartment (urban) with wide open views to the northwest and East. Given the height, I am considering a new Ham setup for QRP. We will have a balcony where I could operate from. I'll probably get a ft-817 and I'm looking at various antenna options.
I am only up three floors, BUT great view to south-west for my Outbacker vertical on the balcony.  I use the counterpoise tripod mount and choke to handle common mode.
Height matters ... great for contests with less than 100 watts, QRP, or QRPp
 :-)
« Last Edit: December 10, 2012, 07:04:15 PM by W9GB » Logged
WX7G
Member

Posts: 6079




Ignore
« Reply #8 on: December 11, 2012, 04:38:15 AM »

I have operated from seven apartments and have some experience with antennas and RFI.

At 5 watts RFI will not be an issue and an unbalanced antenna such as the MFJ-1622 ($100) mounted on the balcony will work. The MFJ-1977 12 ft. telescoping whip can be used to improve performance on 40-20 meters.

http://www.mfjenterprises.com/Product.php?productid=MFJ-1622


Running higher power would certainly help you make contacts. To minimize RF return current on the apartment AC wiring and to reduce RFI a balanced antenna such as the Buddipole would be best.

http://www.buddipole.com/buddipole.html

I recommend a 100 watt transceiver having a built-in tuner. This will allow the antenna to have a VSWR up to 3:1.
« Last Edit: December 11, 2012, 04:44:23 AM by WX7G » Logged
AD5X
Member

Posts: 1430




Ignore
« Reply #9 on: December 11, 2012, 05:37:52 AM »

Look at the "Portable Dipole" article in the "Articles" section of my website at www.ad5x.com.  You'll also see pictures of how it is mounted on a balcony of the condo we enjoy vacationing in Port Aransas (Mustang Island), TX.  Anyway, cheap and works great.

Phil - AD5X
Logged
M6GOM
Member

Posts: 915




Ignore
« Reply #10 on: December 11, 2012, 07:37:51 AM »

If you have a space 8ft x 8ft take a look at the G3TPW Cobwebb. 20-10m fullsize dipoles in a 8ft square.

Steve G3TXQ redesigned it to make it easier to build homebrew.

http://www.karinya.net/g3txq/cobweb/
Logged
KA2ZEY
Member

Posts: 78




Ignore
« Reply #11 on: December 12, 2012, 06:09:12 AM »

Thanks for the replies. I will look into all of these options. I'd like to remain inconspicuous and that can be difficult in a crowded urban landscape.
The box fan loop looks interesting. The one that MFJ makes. The buddistick could be kept in a corner but then you're dealing with an unbalanced setup and having to use radials. I'll keep looking.
Logged
KA2ZEY
Member

Posts: 78




Ignore
« Reply #12 on: December 30, 2012, 08:29:56 AM »

Just wanted to update this thread. For operation on a 15th floor balcony (temporary and discrete setup), I'm thinking of going the route of Alex Loop
and Elecraft KX3 (need to save up) or something like the new Ten Tec QRP rig or a used IC-703 for low power operation. I was thinking of the Ft-817
but the extra 5 watts on the other rigs could help. Can anyone say what kind of performance I can expect from that high up but also realizing that we are
heading into a Sunspot minimum.

Thanks.
Logged
WA2OLZ
Member

Posts: 64




Ignore
« Reply #13 on: December 30, 2012, 05:58:52 PM »

You may find you need to concentrate a bit more on receiver capability than transmit power. QRN in the city can be overwhelming. I've only experienced HF operation in the city while mobile. My TS-480SAT suffers max front end saturation in some areas, was fine in others a few blocks apart.

Logged
VE7TIT
Member

Posts: 62




Ignore
« Reply #14 on: December 31, 2012, 10:11:37 AM »

I was thinking of the Ft-817 but the extra 5 watts on the other rigs could help.
I've gotta say, the FT-817 is a nice little rig, especially when it's connected to a computer running Ham Radio Deluxe so you can access all of the settings easily...

Quote
Can anyone say what kind of performance I can expect from that high up but also realizing that we are heading into a Sunspot minimum.
I don't have any experience with that with operating up that high, but with a good RF ground and/or an antenna that is not heavily dependent on RF ground, I would think that being up that high should be very nice (especially for V/UHF).
The sunspot maximum (as disappointing as this cycle has been Undecided) is still a year off. We're still about six years away from solar minimum, so we've got some time to play yet. Smiley

You may find you need to concentrate a bit more on receiver capability than transmit power. QRN in the city can be overwhelming. I've only experienced HF operation in the city while mobile. My TS-480SAT suffers max front end saturation in some areas, was fine in others a few blocks apart.
That could be argument in favor of the preselection capabilities of a magnetic loop.
Logged
Pages: [1] 2 Next   Go Up
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.11 | SMF © 2006-2009, Simple Machines LLC Valid XHTML 1.0! Valid CSS!