vertical or horizontal for sw pirate radio?

[tech53]

Since most of/all of what i've heard is in marine bands...marine is typically vertical, but shortwave is horizontal...so im confuzzled.

[NJQA]

On SW, polarization gets mixed up after reflections off the ground and ionosphere, so you never know what to expect.  Consideration of whether an antenna is vertically or horizontally polarized is overcome by the question of what kind of gain pattern the antenna has.

On VHF, propagation is usually line of site so the polarization of the receiver and transmit antennas is of more concern.  If cross polarized, you can suffer more than 20 dB of loss, but that is only if you are perfectly cross polarized.  If you installed a beam at a 45 degree angle, you would only be down by 3 dB for horizontally or vertically polarized signals.

Even at VHF you can see reflections off of objects like buildings so the polarization you receive may or may not be what was transmitted.

[KnowFear]

Good info above.

More:
In GENERAL for Shortwave, we want low "take-off angle".  These low angles are generally the angles at which the farthest away stations are received.

Again in general, we get Low Angles from HORIZONTAL antennas that are 3/8 to 1/2  wavelength or higher.  So, 45 feet high or so for 7.5 MHz,  The LOWer the frequency, the HIGHer your horizontal antenna needs to be to get low-angle reception (and transmission), IOW at around 4 MHz, it needs to be up 90 feet or so.

What about when you can't get your horizontal antenna up high enough?? That's when we generally use VERTICAL antennas, because vertical antennas are better at low-angles than low horizontal antennas (but not as good as high horizontal antennas).

Also important to (if possible) put your antennas away from noisy power lines and from your house (with all those noisy power supplies).

Note - there can be exceptions.  For example, short-ish vertical antenna "tend" to pick up nearby noisy power supplies more than horizontal antennas (but not always!).  So, you may receive better with a non-optimal low horizontal antenna than a more optimal vertical antenna - because of noise pickup !!

Why not try a high horizontal AND a vertical ??    But don't get paralyzed by analysis paralysis !! - throwing a random wire into a tree will get you plenty of stations.

[tech53]

Well what I'm using now is a horizontal loop at around 4 or 5 ft high, it's the top bar to my chainlink fence, and I've sanded contact points and jumpered the connection between contact points on each joined bar. So basically  the top bar of a chain link fence and it's resonant around 5 and a half mhz. I can't get a poloe up that high on four locations, I live with my fiancee in the in laws basement, I'm disabled and fiancee is recovering from cancer. Anyway basically I'm fighting pretty hard just for the one 20 ft pole on a 5 ft tripod.i can stick pretty much what I want on it. I DO have the dipole portion of a buddipole antenna, sans "versatee" but that could easily get soldered to a feedline and supports to become a vertical dipole. Otherwise maybe a vertical loop? I'm surrounded by low hanging power lines, it sucks, but it's my reality.

[KnowFear]

A low horizontal loop is generally going to be a "cloud warmer", meaning if you transmitted with it, most of the energy goes straight up, warming the clouds.  That can be ok for receiving near-in and medium-distance stations, but will be quite far down to one of the other antennas mentioned above.

But again, I say "generally", because there can be some exceptions.

If you can, you may want to try comparison against a vertical antenna, or even a vertically-oriented loop.  And of course, it doesn't need to be round - a single rope up in a tree to suspend the apex of a triangle is fine.

One of my fav antennas is the Inverted-L.  if you have a few trees up 25 feet or so, you can (or get someone to help) make a 45 ft or so wire, with 23 ft or so high, 23 feet or so over to the next tree.  It makes a decent all-band RX antenna for 4 MHz or so and up to 30 MHz or more.  A 4:1 "UnUn", or 9:1 at the base gives you a better match, and can help if your signal strengths are down.  Use a groung rod, or your chain-link fence pipes for the "ground" connection to your coaxial cable.

These are all dirt-cheap homebrew antennas that could help, with the possible exception of the "UnUn" matching transformer.

Anyway, your low horizontal antenna is probably not a great choice, assuming you want to receive out to long distances, so trying out other options would probably pay off for you.   The PROOF would be if you keep the old antenna too, and then switch connections in real time to determine which antenna works better.

[Stretchyman]

Depends on frequency.

Transmitting info;

However as most OP's are using frequencies around 6-7MHz the main method of propagation during the day is NVIS so you'll need to use a low horizontal dipole. However at night the ionospheric layers rise higher and the skip goes long so this is the time to switch to a vertical or higher horizontal dipole. The power to maintain a decent signal strength will need to increase (x10).

There's also mechanical and situation constraints that effect the choice of antenna too.

Receiving info;

Anything will do and the longer and higher the better. As mentioned in an earlier post an 'inverted L' being a combo of both horizontal and vertical elements will work well and even better if you use some kind of balun altho' not essential.

Thing to remember that the signals are coming at various angles from the sky rather than (like VHF) over the ground.

Str.

[tech53]

so how about a sloping end fed halfwave? I was bouncing the idea off of ai earlier - time for some human ideas. The idea is i have a 20-30 ft mast on a tripod. It doesn't quite make it above the rooftops here  (most are 2 story houses of a certain design here in milwaukee) but it gets close to rooftop height, and it gets higher above the ground. The thing that worries me is that I'm reading that this may be more susceptible to noise. There are a lot of low hanging electrical and communications lines all over milwaukee. Apparently this city doesn't like the idea of buried cables. Where I grew up everything was buried unless it needed to be above ground...probably due to all the tornadoes. Nehoo...thoughts? I was thinking i could do that and double down by putting a vhf vertical and uhf vertical on top of it spaced out by another 5 or 10 ft obviously. Keep in mind that for now this is receive only.

[Stretchyman]

I'd use the mast as the vertical section (to hold the wire vertically) and then run the rest to a rooftop as the horiz section. Inverted V is another config.
I wouldn't get too concerned with impedance matching etc, just get as much wire up as you can.

Str.

[Synclair]

Hi guys, new here.

It's interesting to read about antennas. I don't broadcast, only receive, so I fall nto the category "any old piece of wire will do for starters".

It has taken me a lot of experimenting - especially since I concentrate on 3-7Mhz, which can be challenging at times. I've got a good set-up at the moment; I suppose its a "dipole" of sorts. two 22 metre wires - one connected to the antenna port and the other to the ground port of a ballun, then directly into a wideband in-line RF amplifier powered by BiasT, which helps tremendously. Its mounted about 2 metres above the ground, between drainpipes ant my wife's washing line (she's an angel for putting up with me) so it apparently brakes the "high horzontal antenna" rule, since its quite low.

It seems to work good right down to MW. I do a lot or lower-frequency Broadcast Station DXing and have had some surprising results. The antenna doesn't do well on LW, though (although there's not much down there these days).

My advice is simply to experiment with different set-ups for reception BUT be very careful for transmission.