Getting back on HF in restricted space

[VK7HH]

So... after a long hiatus, I've decided I need something for HF.

I used to have plenty of space to pop up HF wire antennas, not so anymore. I'm restricted to a space of about 25 metres in my backyard, perhaps slightly more with an inverted V.

The antenna location would be mounted on a mast (probably around 6 metres above ground) immediately above and parallel to my 9m long shed (so perhaps some interaction with open feeder type designs might cause issues).

I've had a look at the Western HF10 - and heard good reports about it, especially for low noise (important here in the suburbs). Also looked at the ZS6BKW.
I've also looked at a trap dipole design, if I can build traps out of coax, or similar (I got a bit of RG316 a while back for such a job).

Primary bands I'd like are 80m, 40m, 20m. 

160m and 10m would be a bonus (especially 1.8MHz, a band I'd like to play with).

Thoughts? What can I build?

Regards
Hayden

[VK2KRR]

How about a magnetic loop
http://www.wimo.com/magnetic-loop-antennas_e.html

[VK4ADC]

http://www.vk4adc.com/web/index.php/hf-p...d-v-dipole

with maybe a couple of extra traps at 7.0MHz to make the inside segment tune to 20 metres.
Don't forget 30 metres either if you are interested in HF digital.. by adding yet another pair of traps at 10.1MHz.

The dipole antenna arrangement I took for my VK9NU outing 2 years ago comprised enough traps such that it covered 6, 10, 12, 15, 17, 20, 30, 40 and 80m in two separate legs off each side of the common balun. The WARC bands were on one wire leg, the standard bands on the second wire leg, the whole thing mirrored. The individual bands were tuned by adjustable droopy tails, with the separation between each trap fixed distances.

Don't forget that the legs of the dipole or V can be other than straight...

There are a few other trapped antenna articles on my web site, plus one about tuning and making traps, if you do a search on it. http://www.vk4adc.com

[VK7HH]

How about a magnetic loop
http://www.wimo.com/magnetic-loop-antennas_e.html

For those prices I could buy a new remote rig.

---

http://www.vk4adc.com/web/index.php/hf-p...d-v-dipole

with maybe a couple of extra traps at 7.0MHz to make the inside segment tune to 20 metres.
Don't forget 30 metres either if you are interested in HF digital.. by adding yet another pair of traps at 10.1MHz.

The dipole antenna arrangement I took for my VK9NU outing 2 years ago comprised enough traps such that it covered 6, 10, 12, 15, 17, 20, 30, 40 and 80m in two separate legs off each side of the common balun. The WARC bands were on one wire leg, the standard bands on the second wire leg, the whole thing mirrored. The individual bands were tuned by adjustable droopy tails, with the separation between each trap fixed distances.

Don't forget that the legs of the dipole or V can be other than straight...

There are a few other trapped antenna articles on my web site, plus one about tuning and making traps, if you do a search on it. http://www.vk4adc.com

Thanks Doug, I did have a browse of your site last night. I'll have a more detailed look later today.

Hayden

[VK2KRR]

You can build a magnetic loop Hayden, was just an example.
http://blog.marxy.org/2012/02/hf-loop-by...vk1un.html

[VK4AQJ]

Many people don't like them, but in my experience, a properly constructed OCF dipole will work extremely well. I never experienced any TVI issues.

I was able to stack 80m and 30m OCF antennas quite successfully, feeding with 300 ohm ladder line to a 6:1 balun. It had the bonus of working on all WARC bands with very low SWR. Stacking will not work with even harmonics.

As an experiment, I then added two 80 metre coaxial traps at the end of the 80 metre OCF and added additional wire for 160 metres. I found that by adding two wires at each end at about 120 degrees, keeping to the OCF 2:1 proportion, I was able to widen the bandwidth. The only drawback was high noise level, but with digital modes like FT8, it was less of a problem.

A high impedance feed lets you get away with a multitude of sins. Make sure you use a balun designed for 160m if you plan to operate on that band.

I can see the attraction of magnetic loops, and I'm thinking of building one as a receive only antenna. On the lower frequencies, they tend to have very low efficiencies on transmit, but they are low noise and able to null out local QRM.

[VK2WP]

In my restricted area yard about 15 mtrs across by 12 mtrs set up a horizontal loop for 40 metres. The loop consists of 41.84 mtrs of wire suspended from poles at each corner of the yard.

The poles raise the loop about 7 metres high. The loop is fed by 450 ohm ladder line with a 1:1 balun.

A short length of RG213 about 500mm comes in through an opening from the balun to an aerial tuner. Its important to keep this length of coax as short as possible.

The loop will tune 80M, 40M, 30M and 20M, have not really tried any higher bands as have a hex beam for those.

Get very good performance for local VK and plenty of dx on 30M and 40M, not really tried the loop on 20 or 80M for dx as yet.

One great attribute of the loop in a suburban location is it is very quiet as compared to a dipole or a vertical.

[VK4WDM]

In my restricted area yard about 15 mtrs across by 12 mtrs set up a horizontal loop for 40 metres. The loop consists of 41.84 mtrs of wire suspended from poles at each corner of the yard.

The poles raise the loop about 7 metres high. The loop is fed by 450 ohm ladder line with a 1:1 balun.

A short length of RG213 about 500mm comes in through an opening from the balun to an aerial tuner. Its important to keep this length of coax as short as possible.

The loop will tune 80M, 40M, 30M and 20M, have not really tried any higher bands as have a hex beam for those.

Get very good performance for local VK and plenty of dx on 30M and 40M, not really tried the loop on 20 or 80M for dx as yet.

One great attribute of the loop in a suburban location is it is very quiet as compared to a dipole or a vertical.

I was going to mention the horizontal loop.  I used one in a previous QTH and found it would work on all bands 80-10m with a tuner and and if I joined both sides of the feed line together it would load on 160m like a Marconi T, albeit with rather poor efficiency.  I worked into the Americas and Sth Africa on 80m using JT65 and plenty of DX on the other bands. Unfortunately I don't have the room to erect it here and have opted for a vertical, which was going to be my next comment.

I made a non resonant 10m high vertical out of aly tube and added a wire extension that drooped down at about 40 degrees to another mast  (so a distorted invert L) over 10 radials. It worked on all bands 160-6m with a tuner. Somewhat noisy but I have a very good antidote for noise, a Timewave ANC-4 "noise canceller.

One of requirements I have for antennas here is that I am able to lower them in a hurry by my aged self should a cyclone or big storm threaten and this "monopole" was a bit too clumsy to do that, so I brought a commercially-made vertical, the Hustler 6-BTV. It is tuned to resonance on 80, 40, 30, 15, 10m and there are simple mods on the web to add 160, 17 and 12m. I have only had it for a couple of weeks but the results so far are impressive.

So Hayden, perhaps a vertical should be in the frame as well.

73

Wayne VK4WDM

[VK2WP]

If the vertical path is the only alternative here is the squid pole aerial which I made up for portable usage. Easy to make with readily available components.
Set it up at home with ground radials and I had the squid in place for a year. Worked very well, lightweight and easy to take down if and when needed.

http://www.philipstorr.id.au/radio/techn...20pole.pdf