I’m looking for some advice about selecting an antenna. I live in an apartment, so I can’t install anything permanent and can’t anchor anything to the house. There is a small backyard about 30ftx30ft, some arborvitaes but no strong trees. My radio is on the second floor. There are also two-story houses behind and on either side. I am currently a technician, planning to upgrade to general in the next few months. Right now I’m mostly interested in 10m and 20m, would also like 2m to reach my local repeater. I plan to use SSB and digital modes. Some possible options I’ve come up with: using a stand like this https://www.dxengineering.com/parts/wmo-18320 with a mast to put up an inverted V, but I haven’t done the measurements and math to see what the angle would be; my initial instinct is that it’s too sharp of an angle to be effective. I also looked at this https://www.dxengineering.com/parts/dxc-expedition or https://www.dxengineering.com/parts/but-hf9v, but I don’t have good line-of-sight with all the houses. I could do the mast stand and a mast with something like this https://www.dxengineering.com/parts/mkr-11-251.
This might be kinda a stupid question, but does the direction of the antenna affect the output of the wave? (Eg, if the antenna is tilted 45 degrees from vertical, is the radio wave it transmits also 45 degrees from anyone else’s vertical antenna?) Or does the wave stay the same (parallel to the earth, but most of the power is just dumped in an unhelpful direction, so it doesn’t transmit nearly as far?)
I know this is silly, but I don’t actually know the answer, and it makes me curious, since I tend to ski with radios, transmitting while skiing down steep slopes while people are above or below me by hundreds/thousands of feet.
This is a great question. There is generally a null point which extends from the top of the antenna such that if you were to point the tip of the antenna at some distant receiver, the signal would be greatly attenuated. It’s not eliminated completely for the same reason if someone is yelling but not facing you; signals can bounce or bleed around and still be intelligible.
When I think about antennas, I like to imagine a donut: 🍩, the antenna extends through the center and the actual donut is the radiation pattern. This is good for mental modeling, but in application there are more things which influence radiation patterns. It’s still a good start.
When an antenna is placed on its side, the closer it is to the ground, the more of its energy is directed into the ground (or it may reflect back and nullify signal coming from the antenna), but for handheld radios (which are most likely VHF or UHF), having sufficient line of sight is what’s needed to have the system work properly, and where one needs to occasionally go through walls or other simple obstructions, a little more power can be helpful.
When skiing as you mentioned, have you been having any difficulty communicating with others in your current setup?
Thank you! I think that makes sense. :)
And for my husband and I, not really. We have 5w handhelds with 5- 15 inch whips. But some friends are on .5w to 2w radios, which definitely aren’t as powerful.
I don’t know if there’s a point at which longer antennas have diminishing returns on UHF (GMRS), But it seems like directionality isn’t too much of a concern, even if people are behind a ridgeline or two.
My pleasure! Depending on the local topography and your level of motivation, you may consider using a GMRS repeater, if it makes sense. You might keep it at the lodge, or in your vehicle. But it’s value is only realized if your repeater is between you and your friends.