Choosing Simplex Frequencies in 2m and 70cm bands

[CoastalDude]

Ok, so here goes. Suppose you wanted to choose 10 frequencies that you could communicate with friends on in an emergency using Simplex only, no repeaters, and you want 5 frequencies in the 2m band and 5 frequencies in the 70cm band. This way, in an emergency your friends could monitor these 10 frequencies for communications. You can't just pick 1 channel as in a wide spread power outage you could have tons of people trying to get information and frequencies could be trampled on.

I know this is a bizarre question and reflects on my beginner status but hoping someone could help me out. The National Calling Frequencies will be swamped, we do not intend to use those.

Obviously we are trying to make 1st contact here, we could switch to another frequency if need be but you have to make contact first

 

[trentbob]

Those Simplex frequencies are very well established. What you see in the listings are correct on every band. It can be a lot of fun.

Ask the park people, they are ramping up now.

 

[nd5y]

How are you & your friends going to monitor 10 frequencies?
How far apart is everybody? Are they using base stations with good antennas or Baofengs with no external antenna?
You could call somebody but they miss the call because they are scanning 10 frequencies and stopped on one that is busy, but you don't know it because you can't hear the other person tying up the frequency.

 

[scanmanmi]

you could have tons of people trying to get information and frequencies could be trampled on.

I highly highly highly doubt this. The ARRL bandplan calls for simplex on 146.4 - 146.58 and 147.42-147.57 and your state may also have a bandplan. I would have a secondary list but always have just one hailing freq. Make contact on the hailing one and say go to channel x . Band Plan

 

[CoastalDude]

How are you & your friends going to monitor 10 frequencies?
How far apart is everybody? Are they using base stations with good antennas or Baofengs with no external antenna?
You could call somebody but they miss the call because they are scanning 10 frequencies and stopped on one that is busy, but you don't know it because you can't hear the other person tying up the frequency.

If an emergency happens we will scan these 10 frequencies for our group. Once contact is made with everyone we will pick one of the frequencies to be our main go-to until otherwise noted. We can always go through these 10 channels if our preferred frequency is tied up. In other words, we go into 1st contact mode again as default if we cannot make contact. We all live within 5 miles of each other, yes on the hand helds, yes on Antenna Diamond Dipole for 2m/70cm bands.

All of our radio's are programmed with the exact same setup regardless of brand, same channel numbers and frequencies and even names, pick up a Yaesu or BaoFeng or Quansheng, all exactly the same on A/B.

We are just adding the 10 channels now. I figured it out, setup some simplex frequencies and just communicated radio to radio without a repeater. So now I'm choosing the frequencies.

 

[ka3aaa]

and everyone in the group has their ham ticket, correct?

 

[hill]

Much simplex activity in Eastern Baltimore County Maryland. Mainly the upper simplex frequencies in 147. Many hams in this area use simplex and don't use repeaters much. Two meter simplex works well even with a short mobile attenna.

If you are going to use this with known people and not random contacts would use a pl tone, so not to hear othe users on the frequency. DCS/DPL would most likely work even better.

 

[mmckenna]

So now I'm choosing the frequencies.

The ARRL repeater guide used to have a page showing the band plans. It was a good place to look.
Most band plans are "gentlemen's agreements", but there's no reason NOT to follow them.

To avoid issues, stick to the established segments of the 2 meter and 70 centimeter bands that are set aside for simplex. The ARRL guide used to give the starting frequency and you'd use whatever step was common in your region. There are many online versions of it, many may be called "incorrect" but as long as you stick in the simplex segments, you'll work it out.

Good for you guys on getting past repeaters. Simplex can do well if people are running good antennas. Unless you live in a metropolis, you'll probably have no issues at all finding quiet simplex frequencies.

 

[hill]

Also aome local repeater coordination groups publish local simplex frequencies.

Some areas use 15 kHz spacing channel and other areas use 20 kHz spacing. You can find a map of what is used in your area online.

Most of the aread using 15 kHz spacing are areas with a large population base with needing more channels. Areas with less population are mainly using 20 kHz.

 

[AK9R]

The ARRL repeater guide used to have a page showing the band plans.

Still available on the ARRL website. Scroll down to 2m and 70cm.

Band Plan

The American Radio Relay League (ARRL) is the national association for amateur radio, connecting hams around the U.S. with news, information and resources.

www.arrl.org

However, the advice to check with your local frequency coordinator is good. They may have a band plan that is more specialized for your area and they may have suggested simplex frequencies.

 

[ladn]

We are just adding the 10 channels now. I figured it out, setup some simplex frequencies and just communicated radio to radio without a repeater. So now I'm choosing the frequencies.

You might also consider adding TX/RX PL or DPL to at least some of the channels. This will mitigate the radios locking on transmissions from stations outside your group. I'd probably choose DPL simply because there are more choices and it seems to be less used than analog PL.

Note: This will keep your radios from hearing other stations, but other stations using open squelch will be able to hear your transmissions.

 

[k6cpo]

The Nifty Guide is the best reference I've found for ALL the bands.

HF / VHF / UHF Bands Operating Guide

 

[CoastalDude]

You might also consider adding TX/RX PL or DPL to at least some of the channels. This will mitigate the radios locking on transmissions from stations outside your group. I'd probably choose DPL simply because there are more choices and it seems to be less used than analog PL.

Note: This will keep your radios from hearing other stations, but other stations using open squelch will be able to hear your transmissions.

I just read it's possible to setup your radio for simplex communication to Transmit on one Frequency and Receive on another? Is that possible? This way any trouble makers can only hear 1/2 the conversation.

So the way I read it was this:

Ham 1 - Sets up Simplex channel to Transmit on Freq 1 and Receive on Freq 2
Ham 2 - Sets up Simplex channel to Transmit on Freq 2 and Receive on Freq 1

Can you program a Ham Radio channel to transmit on one frequency and receive on a different frequency altogether?

I was looking at Chirp and not sure it's possible ... ?

 

[mmckenna]

"Duplex", well, actually half duplex since you can't receive and transmit at the same time with most of these radios.

I don't know about the CCR's, but it should be possible with any ham radio, and it's absolutely possible with reputable commercial gear.

Not really a good security measure, but if it's something you want to try, go for it. Bigger issue is that if during said emergency, someone needs to pick another frequency manually, trying to get someone that only knows how to push a Chirp file into the radio is going to have a hard time with this. Sometimes simpler is better. If you run into issues with someone, just change to another predetermined frequency.

 

[nd5y]

Can you program a Ham Radio channel to transmit on one frequency and receive on a different frequency altogether?

I was looking at Chirp and not sure it's possible ... ?

It's easy In CHIRP. No different than programming an odd split repeater channel.

Program the receive frequency in the "Frequency" column. Then set the "Duplex" column to "Split". Then program the transmit frequency in the "Offset" column. Depending on the radio you could even have frequencies in different bands.

You swap the frequencies for the other radio.

Note that this is a stupid idea and won't work If there are more than two radios and you want everybody to be able to hear eachother. It could work on some radios with dual watch or dual receive but that can create other problems if both frequencies are active at the same time.

 

[ladn]

o the way I read it was this:

Ham 1 - Sets up Simplex channel to Transmit on Freq 1 and Receive on Freq 2
Ham 2 - Sets up Simplex channel to Transmit on Freq 2 and Receive on Freq 1

Can you program a Ham Radio channel to transmit on one frequency and receive on a different frequency altogether?

I was looking at Chirp and not sure it's possible ... ?

As @mmckenna , said, it's possible. You would program the radios like you were programming an odd repeater split. You could also do this cross band (VHF --->UHF / UHF--->VHF), but in reality, this type of programming has the potential to introduce all sorts of errors and makes things unnecessarily complicated. AND, in this scenario, what about Hams 3, 4....? The only way this is practical with more than two operators is to have "base" or "control" Tx on F1/Rx on F2 and have the mobiles/portables Tx on F2/Rx on F1.

Stick with the KISS solution (Keep It Stupidly Simple).

If you're really, really, concerned about ease droppers, get a Part 90 station license and appropriate hardware and go digital + full encryption or frequency hop .

 

[CoastalDude]

It's easy In CHIRP. No different than programming an odd split repeater channel.

Program the receive frequency in the "Frequency" column. Then set the "Duplex" column to "Split". Then program the transmit frequency in the "Offset" column. Depending on the radio you could even have frequencies in different bands.

You swap the frequencies for the other radio.

Note that this is a stupid idea and won't work If there are more than two radios and you want everybody to be able to hear eachother. It could work on some radios with dual watch or dual receive but that can create other problems if both frequencies are active at the same time.

Okay, amazing, so here's what I did ...

Radio One​	Radio Two​

You basically use them with the A/B channels swapped. I tested it out and it works great, I had a BaoFeng in VFO mode trying to snoop on them and indeed it could only hear half the conversation ... This is amazingly cool !! thank you for the tip.

I have Chirp setup like this ...



Notice the offsets are swapped the same amount + or - I freakin' love Ham Radio, I should have got into this a long time ago.

 

[CoastalDude]

Ok, I just realized I only needed to use the A channel on both, setting one to EPW-S1A and EPW-S1B and I had the B channels down in the 440 ranges so they weren't involved, this is super cool

 

[CoastalDude]

Final setup, for anyone that comes along after me ...



Chirp

 

[mmckenna]

A couple of things to keep in mind:

Your 145.300 is in the repeater sub-band, so you could be on repeater input frequencies. Just make sure there are no repeaters in your area using that as an input frequency.

You'll also need to figure out how to add more radios to this setup, unless you are going to scan. That means additional channels that may be congested and prevent communications. Remember, you are supposed to monitor before transmitting to make sure the channel is free.