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Thanks Jamey. Its possible that your antenna has reasonable SWR values within the Ham bands even though the lowest SWR readings are not in the center of the bands.
Can you also post the SWR readings at a few frequencies within each of the bands that the antenna is supposed to work on:
80m @ 3.5, 3.8 and 4.0 MHz
40m @ 7.0, 7.15 and 7.3 MHz
30m @ 10.130 MHz
20m @ 14.0 14.175 and 14.35 MHz
17m @ 18.118 MHz
12m @ 24.940 MHz
10m @ 28.0, 28.5, 29.0 and 29.5 MHz
6m @ 50.0, 50.3 and 50.7 MHzI know that this is a lot of readings so the ones to do/post first would be those for 20m and 40m. I think that you had this same antenna up before? Is that right? If so, do you know if you are seeing significantly different SWR values than before? If so, can you describe how the new mounting location of the antenna changed with respect to:
- Feed point height and proximity to your house
- End of wires height and proximity to your house
- Overall length of the coax feedline change
I see from your original post that the center of your new mounting is higher which is good. Before you try lowering the balun, is there any way that you could get the ends up higher? Maybe with some short poles to bring the ends up to about 15′? This would be the way to go if you can get it to work out.
If you would like to talk about this “live”, give me a call. I should be around or available on my mobile for most of the day.
Hi Jamey,
How does the SWR look on the other bands and in the useful part of 20m (14.000 – 14.350 MHz)? Are the wires near any metal like rain spoutings?
Hello Craig,
The best height to install a dipole is at least 1/2 wavelength above ground.
The wood in your house will be “invisible” to the RF from your antenna. However, metal that is close by and oriented in the same plane as the antenna would be something to think about. Its possible that things like electrical wiring and metal rain gutters could interact with your antenna so it would be helpful to get above the roof by 10 ft or so if you can. The other thing to consider if your antenna is right over you house would be the potential for RF to find its way onto metal objects in your home. At 10m this would like not be too big of a problem unless you use high (500w or greater) power but on lower bands (say 20m, 40m or 80m) this would be a potential problem.
On the soil, its actually the other way around. Its best to have wet, non-sandy soil as this will reflect RF waves the best and will minimize ground losses. Unfortunately, we don’t get this sort of soil conditions in most places here in New England. I hope that this helps you.
73,
Here are a few additional ideas –
- All about High-Altitude Balloons Carrying Amateur Radio – this could start with our HAB platform and build from there. Would include both the Balloon/flight design/tracking/cameras/etc. as well as radio topics like APRS.
- Hands-on Tech Night to set up a Raspberry Pi for Amateur Radio Applications – this could also cover AB1QB’s DX Alarm Clock and the Satellite Tracker that I’ve recently created.
- Antenna matching – all manner of techniques to match antennas to 50-ohm feedlines. Some areas include baluns, unums, load coils, delta matching, gamma matching, how to adjust matches, etc.
- Kit Builds – Mike, K1WVO showed me a really neat touch CW keyer and tone device that is available at modest cost. I am sure that that are lots of good choices here. Would want something that did not cost a lot and could be built in 2-3 hours. Nice if we could do two of these in 2018…
- How to engineer and put up a tower – Topics to include tower types, zoning/permitting, wind load calculations, guyed towers, house bracketed towers, crank-ups, etc.
- Contesting for beginners – basics of contesting, which contests to pick, software and gear, operating techniques, etc.
- All about operating awards – whats available and how to go about earning awards.
Hope that this helps….
Scott and Brian,
Here’s another idea for you for a Tech Night –
How about getting someone to explain how the N1IMO repeater system works?Hi Mike,
How close are you to the mountain? It would have to be pretty close to create and RF shadow. Your takeoff angle is probably 20-40 degrees which would take the mountain mostly out of the picture unless its close.
Why don’t you have the person in Oregon reach out via my email on QRZ? I’d be happy top help them with a NH QSO.
Hi Mike,
How much power were you running and do you have any idea how much the station in Oregon was using? It could also be due to a difference in noise levels in the two locations – given where you are, I’m guessing it could be pretty quite. If the Oregon station was near a city, the noise levels would be higher.
You should not have to do anything special to work that part of the US from here although you would want at least 100W if you are trying to do it with a wire antenna.
We had a chance to look at the data recorded by HAB-2’s flight computer today. Here’s some data from the actual burst –
- Max. Altitude: 35,955 m (117,962 ft)
- Pressure At Burst: 0.73 mB ( < 1% of pressure at launch)
- Temperature At Burst: -1.1 C (30 F)
- Coldest Temperature Recorded: -56.6 C (-70 F) @ ~47,000 ft during decent
We experienced significantly colder temperatures compared to our last flight and we see evidence of temperature impacts on the camera batteries and the Flight Computer GPS. More to come as well look at the data.
It looks like we will have nice weather for our launch today. We expect to launch around 11 am ET from Winchester, NH. We will be carrying a 2m ARPS Tx operating on 144.390 MHz using the call sign N1FD-11. You can also track us on aprs.fi. You can find more tracking information and links here.