# Tag Info

27

The simplex calling frequencies (146.520/446.000 Mhz) are intended for FM simplex communication, while the other pair (144.200/432.100) are for SSB. In general use, the term "simplex" implies FM modulation since FM is commonly used in both simplex and duplex operation. SSB, CW, and other modes are generally used for longer distance, simplex-only ...

18

Most countries follow the band plans that disallow contesting on WARC frequencies, which include three narrow slices of shortwave frequencies at 30M, 17M, and 12M. If you stick to these frequencies you will rarely, if ever, be bothered by contests. It's a small slice of spectrum though, so you might simply consider doing what some amateurs do and simply ...

12

$$\frac{c}{ \text{frequency}} = \text{wavelength}$$ $$\frac{c}{ \text{wavelength}} = \text{frequency}$$ The above relation is a fact of physics. It's true unconditionally (provided you are using consistent units, e.g. wavelength in meters and $c$ in meters per second); it's how you convert between two different ways of measuring a wave. The frequency ...

10

This is indeed in the FCC regulations. In Part 97, section 305 regarding "Authorized Emission Types" there is the following chart which lists two relevant subbands, see in the VHF group the 6m row and the Do ditto right below it: Tracing our way outwards from there, we find: 47 CFR §97.305(c) is the heart of the FCC regulation on which the ARRL legend note ...

8

It is simply an error or typo on that website. Take a look at the companion color chart on that page that is provided by the ARRL. It shows that frequency range as 160 meters. The formula for converting a frequency $f$, in MHz, to wavelength, $\lambda$, in meters is: $$\lambda=300/f \tag 1$$ It is clear from inspection of the formula that wavelength is ...

8

It is probably due to the fact that Canada does not include 420-430MHz in their 70cm band plan. The United States agrees not to allow their amateurs to interfere, by restricting 420-430MHz north of Line A and east of Line C. (See also FCC Title 47 Part 97.303.m which I can't find a good way to link to.) When the manufacturer decides to restrict 420-430MHz, ...

7

A relevant rule your license requires is: Each station licensee and each control operator must cooperate in selecting transmitting channels and in making the most effective use of the amateur service frequencies. (FCC Part 97.101(b)) While spamming multiple channels with the same transmission will save you time, it clearly isn't the most effective use of ...

7

144.200/432.100 are intended for SSB Modulation. 146.520/446.000 are intended for FM Modulation.

6

That's a lot of words for digipeater. These are stations that listen for digital messages, record them in temporary storage, then re-transmit them. This particular allocation is on a secondary basis, with the primary allocation going to AMTS. "message forwarding system" is defined in §97.3: (32) Message forwarding system. A group of amateur ...

5

Ron points to the band plan and that's where you should start. I've redacted it somewhat to the bands most appropriate for simplex work. Note that depending on where you are, there might be large chunks of the repeater frequencies unused. Or you could live between two major metropolitan areas like me where there are NO unallocated repeater pairs...If they ...

5

The names make a kind of sense if you take into account the history behind them. Look at this pattern of names and lower end of the allocation: 80m: 3.5MHz 40m: 7.0MHz 20m: 14MHz 10m: 28MHz Note how the frequencies and canonical names are related by multiples of two. 80m is almost perfectly named: the allocation goes from 75.0m to 85.7m. Sure, as you go up ...

5

On the west coast USA there is a slow CW traffic net that meets each night on the 80 meter band. The rules for this net is nothing faster than 10 wpm. It is a dual purpose net, teaching traffic handling skills and available for those who are not up to the CW speeds for a regular net. The regular CW traffic nets are about 20 wpm on average. So, that is one ...

5

QRS actually means "Please slow down" and is not really defined as a specific speed. So basically what they are trying to do is be as inclusive as possible. When I earned my Novice license in 1971 the speed required was 5 wpm. Then when I earned Advanced in 1977 it was 13 wpm. I am studying now for the Amateur Extra, and am amazed that there is no ...

4

"I'm noticing that using this formula for many bands the resulting frequency doesn't fall within the suggested frequency range for that plan and where they do, many don't fall within any discernible tolerance of the middle." Here's why this is the case today. In the early days of radio (that is, the late 19th and early 20th centuries) everyone referred to ...

4

Here in the US ham radio is only a secondary user of the 70cm band, with the primary user being military radar. That didn't stop ham operators from setting up hundreds of repeaters on the band. Back in 2007 the US Air Force complained about interference, and the ARRL worked with them to create a plan to reduce the interference (article). I don't remember ...

4

The lower the frequency, the larger the antenna that is required to be resonant, so if you're aiming for something small then 10m might be best. That band is usually best during the day, and during the summer. If you want to go with a slightly longer antenna, 15m is also good, either day or night. As for the antenna being indoors, that could work, but ...

4

There are a number of sites attempting to document HF digital band plans. You'll have to poke around a bit, though, since people are experimenting. An internet search for "HF digital band plan" will provide new links as the following links go stale or change URL: http://www.arrl.org/band-plan http://www.bandplans.com/?band=All http://sharon.esrac.ele.tue....

3

As pointed out by @Michael Kjörling, the answer is different for different regions of the world. The DARC (German HAM Radio Club) published a rather good overview over the preference frequencies for different digimodes on the HF bands valid for the IARU Region 1 (Africa, Europe, Middle East, northern Asia): CW: 1'810-1'838, 3'500-3'580, 7'000-7'040, 10'100-...

3

Depending on what you're testing, The safest bet is through a SWR meter into a 50 OHM dummy load, or an attenuator into a spectrum analyzer.

2

The D-Star simplex frequencies in the UK are 144.6125 MHz, 438.6125 MHz and 1298.6125 MHz.

2

This may be a hold-over from when amateur licenses required Morse code. In the US, the entry level license (Novice) required 5 words per minute, and the next two levels required 13 wpm and 20 wpm. Novices were restricted to a few small sub-bands on HF, so it was common to hear and use Morse at slower speeds there. I can't find the details of Morse ...

2

I'm from Serbia, and there we have radio-location service as secondary user in almost whole (both ham and commercial) 70 cm band. In practice, this means ground-based or space-based RADARs. Space-based are following ITU-R SA 1260-1, which being only 15 pages long, I recommend that you read. It contains lots of interoperability information and tells you a bit ...

2

It sounds like your study guide is conflating a few issues, and oversimplifying others. Firstly, in antenna engineering, there are concepts of physical length and electrical length. Physical length is measured with a ruler, and is pretty straightforward. Electrical length how long the antenna seems to the currents travelling in them. For example, a ...

2

The ARRL band plan shows: A band plan refers to a voluntary division of a band to avoid interference between incompatible modes. Listen through the simplex range of frequencies from the chart. Listen some more. If the frequency(ies) you choose are not in use, by all means throw your call out with "Is this frequency in use?" a few times - then go ahead ...

1

Simplex implies transmission and reception on the same frequency without using a repeater. The band plan specifies that no repeaters are ever to transmit or receive on calling frequencies, nor should other operating modes, such as cross-band communication or remote control use them. In addition, it is expected that you can make initial contact on the calling ...

1

Correction. Simplex is a mode of communication regardless of frequency band or modulation being used. Simplex in Amateur Radio is one way communication at a time between two communicating stations. When simultaneous transmission is used with capable equipment, it's called full duplex, meaning both stations can transmit and receive at the same time. There ...

1

One of my approaches to avoiding contests is operating on the opposite end of the band. During a big contest weekend it can be tough to avoid, when calling CQ, and someone comes back with ID and contest requirement, so the best thing to do is find the extremities of the band. Usually it's the upper end of the band, like for instance on 20 meters, I'll just ...

1

It appears that the simple legal answer is YES, BUT. Transmitting on multiple frequencies is not illegal. You mentioned both 146.340 and 146.940, and those require some care: If you are on 146.94 that is often a repeater output which would have an input on 146.34 - so even if you can hear people there, it is less likely that they would hear you on that ...

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