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eHam Forums => Elmers => Topic started by: KE7KXS on November 10, 2017, 10:36:56 AM



Title: FT-991A Short apartment antenna for 40m?
Post by: KE7KXS on November 10, 2017, 10:36:56 AM
Hi,

I just got my radio and can get on local 144/440 FM repeaters just fine.

I'm wanting to try SSB, but it appears my home built stick antenna might not emit well.

I can't really afford to buy a nifty antenna, and the space is very limited as I'm on a 3rd story apartment. No railing or balcony.

Could you suggest a home brew antenna I could use?

Also, what is the best way to test that my RF reaches out?

Thank you, Caesar.


Title: RE: FT-991A Short apartment antenna for 40m?
Post by: WW7KE on November 10, 2017, 10:45:12 AM
Hi,

I just got my radio and can get on local 144/440 FM repeaters just fine.

I'm wanting to try SSB, but it appears my home built stick antenna might not emit well.

I can't really afford to buy a nifty antenna, and the space is very limited as I'm on a 3rd story apartment. No railing or balcony.

Could you suggest a home brew antenna I could use?

What kind of construction is your apartment building?  If it's wood-frame with no stucco, you might get away with an indoor dipole or loop strung around the ceiling, fed with ladder line.  I've used those in frame apartment buildings with success.

If you're in a steel-and-concrete or stucco-encrusted building, it'll be much more difficult to get out with an indoor antenna.  I'd use low power (50 watts or less) in any case, especially if you're not on the top floor.

Quote
Also, what is the best way to test that my RF reaches out?

Listening on an internet remote receiver, or making local QSOs first, would be a start.


Title: RE: FT-991A Short apartment antenna for 40m?
Post by: K0UA on November 10, 2017, 11:04:30 AM
Using WSPR would be another way.  If you are not set up for digital you can use the Reverse Beacon Network on CW.  Just Call CQ with your call a few times and go to the reverse beacon network, and look for your callsign, and see how far you got.

Any chance you can let out an end fed wire?

http://www.reversebeacon.net/

http://wsprnet.org/drupal/wsprnet/map


Title: RE: FT-991A Short apartment antenna for 40m?
Post by: KU3X on November 10, 2017, 11:41:58 AM
Build a magnetic loop and put it next to a window.
Barry


Title: RE: FT-991A Short apartment antenna for 40m?
Post by: KE7KXS on November 10, 2017, 03:09:18 PM
All great suggestions! Thank you, I'll give them a shot.

Q: how would I listen to a remote internet receiver?

Thank you, Caesar.


Title: RE: FT-991A Short apartment antenna for 40m?
Post by: K0UA on November 10, 2017, 04:47:57 PM
All great suggestions! Thank you, I'll give them a shot.

Q: how would I listen to a remote internet receiver?

Thank you, Caesar.

Check out some of the links on this page..

https://www.dxzone.com/catalog/Internet_and_Radio/Online_Receivers/


Title: RE: FT-991A Short apartment antenna for 40m?
Post by: WA3SKN on November 11, 2017, 02:24:07 PM
OK, third story apt.
Do you have a balcony or the dreaded "picture window"?  Are there ANY windows near the radio setup?

-Mike.


Title: RE: FT-991A Short apartment antenna for 40m?
Post by: KH2BR on November 13, 2017, 11:02:42 AM
When I was single in the Air Force barracks, I used a steel safety wire end feed long wire. It could not be seen.


Title: RE: FT-991A Short apartment antenna for 40m?
Post by: G8JNJ on November 13, 2017, 11:48:51 AM
More internet WEB SDR receivers around the world can be found here

http://www.websdr.org/

and here

http://rx.linkfanel.net/

Very useful for remote listening and various antenna tests.

Regards,

Martin - G8JNJ

SUWS Web SDR            -   http://websdr.suws.org.uk
SWUK KiWi Web SDR    -   http://southwest.ddns.net:8073/



Title: RE: FT-991A Short apartment antenna for 40m?
Post by: KE7KXS on November 15, 2017, 06:24:11 PM
Hi Martin, Thank you, I'll check those out.

At the moment, I've tried out a simple horizontal 10m loop antenna housed in another room. It seems OK, SWR is about 2.0, but I haven't made any contact with it.

I splurged a little with this week's paycheck and got a BuddiPole, but setting it up as a vertical. It's a little more versatile for other bands, and takes up very little space.

I've tried WSPR with both antenna and I don't seem to be heard anywhere. How does it take from transmission to get on the map anyway?

Cheers, Caesar.


Title: RE: FT-991A Short apartment antenna for 40m?
Post by: KE7KXS on November 17, 2017, 10:34:41 AM
During antenna testing, it turns out the settings on my radio wasn't complete.

Fixed, I can be heard using the 10m homebrew loop antenna (quad). I used a full wave 10m wire length. Currently testing it with 40m as a quarter wave antenna.

The BuddiPole will be useful outdoors in the Spring/Summer/Falls.


Title: RE: FT-991A Short apartment antenna for 40m?
Post by: ONAIR on November 17, 2017, 06:07:37 PM
An end fed antenna might work for you!  You could run a 10 foot PVC pole horizontally out your window, then string the wire through it and allow the rest to dangle down at a 90 degree angle towards the ground.  The "Ultimax-100" end fed antenna might be suitable, as it is only 24 feet in total length.


Title: RE: FT-991A Short apartment antenna for 40m?
Post by: VA7CPC on November 18, 2017, 12:34:51 AM
If you're on the third floor, and you're willing to be visible, and you have an openable window:

Get a 31' windsock pole from J-Kite.  Lightweight, collapses to 4' long.  (There are similar poles from Spiderbeam, heavier, more expensive).

Build a dipole antenna for 40m, with lightweight loading coils (I wound mine on 2-quart Pepsi bottles -- very thin and light coil forms!).  Make each leg about 20' long, and put a loading coil in the middle of each leg.  You can find calculators online, for correct loading-coil inductance and construction.

Put a coax connector at the dipole feed point.

Tie the center-point of the antenna to the end of the pole.  Tie the ground-side of the antenna to the pole.

Connect coax from your rig to the center-point.

Now, drop the free end of the dipole out the window, and extend the pole out the window as far as is comfortable.  Tie it in place.

So you have a V-shaped dipole -- one leg hanging, the other tied to the pole.   It's 40' long, total -- not bad for a compromised 40m antenna.   And it's _all_ outside the house.

With a similar antenna, working from a balcony, I had reasonable results, working over the US Southwest from Vancouver BC.

Antennas are one of the sub-hobbies (within ham radio) where you can experiment at fairly low cost, and get surprisingly good results.

.      Charles


Title: RE: FT-991A Short apartment antenna for 40m?
Post by: KE7KXS on November 19, 2017, 11:28:09 AM
My window is openable but the HOA frowns on having things attached to the outside wall (HOA's property).

I'll play more indoors, I currently have a 10m loop which works reasonably well (WSPR shows me out to the Gulf Coast at the furthest).

I'm going to try an inverted L, a delta loop (horizontal & vertical).

Yes, I did the same loading coil when using the 10m loop for 40m :-)