Being still a boy at heart I want a set of walkie talkies. Since the guys would look at me funny if I got the Hello Kitty model I’m looking at Motorola FRS radios. What I want to know is what excactly to the “interference eliminator codes” do exactly. As I understand the codes do not extend the 14 channels available, but what exactly do they do? Is it worth paying a few bucks more for the feature?
Here’s the deal. In the FRS radios there are 14 frequencies (channels). Seven of these are shared with the GMRS service.
There are two methods of “interference elimination” authorized.
In one case the interfearence eliminator transmits a ‘sub-audible’ audio tone. This is called CTCSS (Continuous Tone Coded Squelch System) The receiving unit won’t open it’s squelch unless it’s set to the same tone. So if two sets of folks are on the same channel and using two different codes (tones) they won’t hear each other. Unless! Both parties transmit at the same time, or one party is not using any tone at all. In this case there will be some interfearence.
The other method is DCS (Digital Coded Squelch) it works as above, but uses digital data rather than audio tones.
I thought that all of the units currently on the market used one system or another. Some may have both systems available for you to choose from.
Thanks Gary, that made it much more clear than anything else I could find. I can live without that when I can get a pair of radios for $20
You will very rarely find DCS (digital coded squelch) on any but the highest priced units.
One of the common misconceptions about “interference eliminator” is that it will allow 38 different people to talk on the channel.
It will not - the only thing the “interference eliminator” CTCSS tones will do is not open the squelch unless the unit “hears” the right tone.
And that’s exactly what the tone is. They range from 67 Hz to 250.3 Hz. Too low for the small speaker on the units to reproduce, so you will never hear the tone. But if you were to hook up a good speaker to the unit, you would hear the higher pitched (200 Hz and above) tones.
Here’s a page about CTCSS tones. Disregard anything having to do withe the Delaware amateur radio repeaters, the first part is simply a good explanation.
And if you want to monitor your FRS transmissions on a scanner, or are simply interested in where you’re broadcasting on the band, here’s a list of the frequencies:
Channel…(MHz)
1… 462.5625
2… 462.5875
3… 462.6125
4… 462.6375
5… 462.6625
6… 462.6875
7… 462.7125
8… 467.5625
9… 467.5875
10… 467.6125
11… 467.6375
12… 467.6625
13… 467.6875
14… 467.7125
The codes stop you from listening to other people who are using the same frequency but different sub-code. If you are talking to someone on sub-code 22, then anyone can listen to you on the same frequecy if they listen to sub-code 22, sub-code 00 or do not have the sub-code feature. If you have the digital sub-codes, then it is a bit more private.
If you are using them at a venue (sporting event, amusement park) where many people may be using them, then you will want the eliminator codes. If you are on channel one without the eliminator codes, then you get to hear everybody elses conversations that are on that frequency. Likewise, if you have the eliminator code set to zero, then you are using it like it doesn’t have the feature. Having the sub-code set allows you to not hear conversations other people are having.
$20 seems like a decent price for goofing around, though…
Be warned that even if you are using the subcodes that if you are in a location where lots of people are using them then you will be getting lots of cross interference. I took them on a family trip to Universal Studios back in October and we finally just gave up on them. On the other hand, we found them extremely useful while skiing at Lake Tahoe last year.
This may be a silly way to look at it but wouldn’t the eliminator codes tend to encourage stepping on each other’s transmissions? If you can hear all the conversasions you switch to a quieter channel. Does that make sense?
Anyway I thikn it’s good I can justify not getting a feature. I was going to buy a free after rebate set but they had no headset jacks. These Motorolas are $20 for a pair after rebate. If I decided I needed the codes I’d spend more, then justify recharchable batteries…then VOX, then before I know it I’m sending off an check for a GRMS license and buying $100 radios.
In a high use area as mentioned by tanstaafl you are going to have some problems with or without the codes. Just somewhat less with the codes.
A unit with the ability to “lock” the frequency/codes is worthwhile as it’s easy with some units to change the channel/code without realizing it. Then you wonder where everybody went.
I have a set of the first Motorola’s and these’s no channel lock. It’s easy to bump the setting off the channel you started with.
Most of the Motorola’s have a rounded bottom on the case which means that they won’t stand up. I find that an annoyance.
I’m a ham so don’t use the FRS radios unless I’m with some non-hams. The FRS radios do have their place. I also have a GMRS licence which allows the use of higher power units than the .5 watts the FRS units are limited to.
GaryM, maybe you can clear something up for me. I looked at the GRMS license application and understood it was for me or my family to use the radio. If I wanted to get a pair of radios so my soon to be wife and I could use them would we both have to get licenses and call signs?
The GMRS licence is for a FAMILY. That means you, Mrs. Eye and all the little Eyes, if any, as well as Mr. & Mrs. Eye Senior can all operate under the same callsign. The rules say members of your “immediate family” are covered by your licence.
GMRS pirate (unlicensed) operation are a big issue because the GMRS/FRS radios sold at RS and other stores don’t emphasize that the license is required to use the GMRS frequencies.
Here’s a site with lots of good information http://www.gmrsweb.com/gmrs.html
It should keep you busy for a while.
Heh. This is pretty much exactly what I wound up doing.
I started out with a $20 pair of Audiovox cheapies that didn’t have CTCSS and were pretty bare bones on features (they do have headset jacks, though). I liked them, and had a lot of fun with them, but discovered after a trip to Disneyland that I really wanted something with codes.
A few weeks later I bought some Cobra GMRS radios and an FCC license. The total cost wound up being almost 10x what I paid for the first set.
The nice thing about the codes isn’t that it cuts down on intereference, it’s that you don’t have to hear other people talking when you don’t care who they are. In general, I’ve found that it’s pretty rare that there are people constantly talking on all channels, but there will be infrequent traffic on all channels. With the codes, you’ll most likely only hear those in your party, even if there is a little intereference, you can usually work around that.
However, I don’t think I need the whole GMRS package. I really think if I had just gotten a pair with the sub-codes when I started, I would’ve been fine and wouldn’t have felt the need to drop so much on the new set.
So I’d suggest spending a little more on FRS radios with CTCSS, I do think that’s worth the extra cost. I don’t think GMRS is worth the extra cost, though.
Thanks Gary, that site is extremely helpfup. I’ll start with an inexpensive set of FRS radios and see if it would be worth it to get licensed and get GMRS.
More to ponder. For another $15 I can get the T5420s with CTCSS and vox… I can always add ni-cads later or see if will work with AAA NiMH batteries in place of alkalines. Will come in handy on a camping trip this summer…
The T5420 units have the CTCSS as well as the lock feature to prevent unintended channel changes. I’m sure you could use NiMh cells instead of Nicad. But the charger may not be optimized for NiMh, so the cells won’t last as long (recharge cycles)
If you are only going to use them on an occasional basis I wouldn’t bother with rechargable cells. They’ll always be dead when you wanted to use the radios!
Some friends are full time RV’ers and use rechargables because they use the radios every day.
Good point Gary, I use NiMH in my digital cameras and know how badly they self discharge. I have a pair of 1 hour chargers anyway so it would just be the cost of the cells, maybe $10 and they should have twice the capacity of a similar size NiCd pack. Going on a camping trip this summer where I know there is no cell phone service so I can justify the radios.
Padeye, could you tell me who has the free-after-rebate set? I already own a decent pair of Motorolas, but I could use another pair of cheapies for occasional use.
Fry’s Electronics, they’re Conair radios. http://conairphone.com/Pages/specialty_pages/FRS200SLV.html $15 each with two separate rebates. I probably would have just gotten them but they lack a headset jack.
Fry’s online has them but I don’t know what rebate deals. Check http://www.outpost.com/ and search on FRS and conair