11
votes
Accepted
Difference between antennas for Wi-Fi vs. ham repeaters
In order to use the same antenna design at different frequencies, "all you need to do" is scale all elements of the antenna proportionally to the difference in wavelength. For example, if you take a ...
- 24.5k
11
votes
Accepted
How to do APRS in real wilderness?
So you want to broadcast your location using backpack-portable equipment from deep in a narrow valley hundreds of miles from civilization. I'll assume that you would also like the ability to get a ...
- 9,212
9
votes
Beginner listening to a repeater - only hearing one station
It is presumed that you were receiving on the 2m band.
It appears that you were listening in, using 'repeater reverse' mode. In other words, you were listening in on the repeater's input frequency ...
- 757
7
votes
Accepted
Connecting two sites in the Arctic and Antarctic with a HUGE equatorial repeater? (Science fiction story advice)
Suggestion to OP (and all hams): Play with VOACAP Online to get a feeling for HF propagation.
For example here is the whole path:
And here is the expected probability of communication on a few ham ...
- 11.2k
7
votes
Accepted
How can I be sure I'm actually hitting the repeater?
The simple answer is to transmit on the repeater's input frequency, saying something like " < your callsign > testing" and listen for the repeater's courtesy beep (assuming there is one) on its ...
- 1,035
4
votes
Beginner listening to a repeater - only hearing one station
The concept is called "offset". The repeater is listening on one frequency, and is repeating it verbatim in real time on another frequency, but typically at a higher power so more people can hear it ...
- 777
4
votes
Accepted
Line of sight from geographic/map data?
I've used this one several times.
added:
Go to the graphic under: Surface Elevation Tool.
Scroll (zoom out to speed things up) OR use the search to get to your geographic area. Search somewhat ...
- 1,035
4
votes
How to do APRS in real wilderness?
Apart from matured and highly reliable commercial satellite-based services, WSPR can be another 'DIY/experimental' alternative for broadcasting your location from wilderness. See examples for balloon, ...
- 562
3
votes
Line of sight from geographic/map data?
Google Earth Pro (now free. $0) has a Viewshed tool.
"A viewshed is the geographical area that is visible from a location. It includes all surrounding points that are in line-of-sight with that ...
- 149
3
votes
Line of sight from geographic/map data?
HeyWhatsThat is a free web app that can show you the view from any location and elevation. From what I've seen (I haven't used it seriously), it's a bit clunky but it does the job.
You can also see a ...
- 24.5k
3
votes
Accepted
How to plot transmitter coverage area?
The Longley-Rice model is a fairly common technique. However it's not a simple formula, and so requires some kind of software to implement. Unfortunately my favorite such tool, CRC CovWeb, has gone ...
- 51.7k
2
votes
How to plot transmitter coverage area?
There is a web application already:
https://www.ve2dbe.com/rmonline_s.asp
73, Brian, ZL1IE
- 29
2
votes
Connecting two sites in the Arctic and Antarctic with a HUGE equatorial repeater? (Science fiction story advice)
With infinite resources but real technology, how would you best connect two ideal sites in the Arctic and Antarctic with an ideal, well-equipped equatorial repeater?
Skip the repeater, this calls for ...
- 16k
2
votes
Ham radio and repeater usage
Typically you would connect by both talking to the same repeater. The point of the repeater is to put an antenna up really high so that you both can reach it. Repeaters typically have a 50-100 mile ...
- 6,245
1
vote
How to calculate passive repeater gain?
As I suspected, interposing a passive repeater does not somehow magically just add in a bunch of additional gain. The key reason why not stems from this error in my initial question:
Basically the ...
- 7,411
1
vote
Connecting two sites in the Arctic and Antarctic with a HUGE equatorial repeater? (Science fiction story advice)
You may have prematurely eliminated some of these options, so for the sake of completeness I'm listing everything.
My first thought is that the best solution would be a fiber optic cable. We've been ...
- 6,245
1
vote
Ham radio and repeater usage
Please note that some repeaters are chained together in a network so that boinking one nearby repeater with your Baofeng will light up the entire chain, tremendously increasing the useful range of a ...
- 967
1
vote
How can I be sure I'm actually hitting the repeater?
Ideally a typical repeater when you stop transmitting will have a short delay, the courtesy tone (it's courtesy to wait for that tone so that other people can get a chance to break in), and then ...
- 6,245
1
vote
How can I be sure I'm actually hitting the repeater?
Personally, I don't hear the repeater "tones" or "static" in a consistent of enough way to use them to quality test my transmission to repeater. Maybe my ears aren't refined enough ...
- 11
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