A Uneducated Question

[Daniel_Boone]

My family members owns a vast array of Motorola 2 way walkie talkies.
The most recent acquisition was a pair of T 7400 radios.
While hunting a couple of years ago, we were able to hear radio transmissions from a plumbing contractor - about 5 miles away.
They were transmitting on a GMRS frequency.

Now our walkie talkies are a honest 1 watt right?

His thoughts was that if we used the right frequency and the right tones that we could use their repeater for our radios.
Now I am smart enough to know and understand that it just doesn't work that way.
But I am having a hard time explaining all this to my brothers.

So my question has to be - is the Walkie Talkies that we are using capable of transmitting on the exact frequency with the exact same tone - in a way that would allow us to use the repeater for free?

Motorola says yes - while I say no.

The other question that I have been trying to answer was range of transmission and receive.
Someone was kind enough - not too long ago to make a picture of a guy standing on the top of a mountain and being able to talk down both sides, while another person was standing on the ground on the one side of the mountain - and another person was standing on the other side of the mountain - and neither could talk to the other - because they had the mountain between them.

Now I can understand this and you can understand this - because UHF is like a flashlight and unless you are Buck Rodgers - you cannot get your flashlight to shine though the side of a hill
'But Motorola puts these exaggerated claims on the bubble pack walkie talkies in the hopes of getting people to buy them.
When I try to explain line of sight communications - these people shake their heads up and down as if they understand - and they are not uneducated people - yet they think that their radios are special somehow and that they defy the laws of communications - which as far as I know has not changed much in the past 70 years...

When I try to explain to them that their communications is limited by the size of the radio and the length of the antenna on the radio - they don't seem to understand and they tell me that they do not want to buy a walkie talkie that is rated for 30 miles - because they don't want to talk that far.
I keep trying to explain to them that in the woods of Pennsylvania that they would be darn lucky to transmit 3 miles and that all it would do would be to help their radios transmit a little better between hunters and that it would not become a super transmitter where they can start their own little radio station with nothing more then a hand held walkie talkie.

If someone could be kind enough to post the link to the other reference - as per how the radio waves reacts to the hills / mountains - I would be most appreciative.
Thanks

 

[Spankymedic7]

Hi Daniel,

OK, I'll break down your message and try to answer your questions one piece at a time.
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"His thoughts was that if we used the right frequency and the right tones that we could use their repeater for our radios.
Now I am smart enough to know and understand that it just doesn't work that way."

I'm afraid it does work that way... Yes, if you program the correct frequency(ies) and PL tones, you can operate via a repeater. However, a repeater operates "semi-duplex", i.e. it RECEIVES on one frequency, and TRANSMITS on a different frequency (usually 5MHz higher on UHF). Most repeaters utilize a PL tone ("privacy code") in an attempt to avoid unwanted transmissions.

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"So my question has to be - is the Walkie Talkies that we are using capable of transmitting on the exact frequency with the exact same tone - in a way that would allow us to use the repeater for free?"

You need permission from the repeater owner before using his/her repeater (GMRS). Although the FCC doesn't state that repeater usage is "chargeable" per se, it is ultimately up to the owner. He/she MAY charge for purposes of repeater upkeep/maintenance only.

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"The other question that I have been trying to answer was range of transmission and receive.
Someone was kind enough - not too long ago to make a picture of a guy standing on the top of a mountain and being able to talk down both sides, while another person was standing on the ground on the one side of the mountain - and another person was standing on the other side of the mountain - and neither could talk to the other - because they had the mountain between them."

That's the best way I'd use to explain how a repeater works. Whoever used that as an example did well in explaining it that way.

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"When I try to explain to them that their communications is limited by the size of the radio and the length of the antenna on the radio - they don't seem to understand and they tell me that they do not want to buy a walkie talkie that is rated for 30 miles - because they don't want to talk that far."

I don't know exactly what you're saying here, but what I can tell you is that communications are by no means limited by the size of radio and length of antenna. Let's use this thread, a repeater (and other associated equipment) allows me to talk with my buddy in Florida...and I'm in Wisconsin, all with nothing more than a 5 watt handheld radio on both ends. Now, in terms of "direct" communications, that statement still is not accurate. I can quite easily communicate with another HAM a couple miles away, depending on a few things...

1) Frequency/band used. Typically signals travel farther on HF than they do on VHF, and VHF farther than UHF, and so one. This is assuming that power output is constant/unvariable.

2) Antenna used (and not just "length").

3) Weather/atmospheric conditions. It's not uncommon to have VHF/UHF signals travel several hundred miles along coastal areas by a phenomenom called "tropospheric ducting".

4) Terrain/obstructions. This is the "great equalizer"...trees, buildings, etc. can significantly reduce ANY radio signal, so the other three examples are ofcourse relative to this one. You can talk on an HF frequency (one that is typically/regularly used for worldwide communications), but if you are surrounded by trees, you're hardly going to talk countywide.

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This is a bit lengthy, but I hope it helps. If you have any other questions, feel free to send me a private message.

 

[gewecke]

My family members owns a vast array of Motorola 2 way walkie talkies.
The most recent acquisition was a pair of T 7400 radios.
While hunting a couple of years ago, we were able to hear radio transmissions from a plumbing contractor - about 5 miles away.
They were transmitting on a GMRS frequency.

Now our walkie talkies are a honest 1 watt right?

His thoughts was that if we used the right frequency and the right tones that we could use their repeater for our radios.
Now I am smart enough to know and understand that it just doesn't work that way.
But I am having a hard time explaining all this to my brothers.

So my question has to be - is the Walkie Talkies that we are using capable of transmitting on the exact frequency with the exact same tone - in a way that would allow us to use the repeater for free?

Motorola says yes - while I say no.

The other question that I have been trying to answer was range of transmission and receive.
Someone was kind enough - not too long ago to make a picture of a guy standing on the top of a mountain and being able to talk down both sides, while another person was standing on the ground on the one side of the mountain - and another person was standing on the other side of the mountain - and neither could talk to the other - because they had the mountain between them.

Now I can understand this and you can understand this - because UHF is like a flashlight and unless you are Buck Rodgers - you cannot get your flashlight to shine though the side of a hill
'But Motorola puts these exaggerated claims on the bubble pack walkie talkies in the hopes of getting people to buy them.
When I try to explain line of sight communications - these people shake their heads up and down as if they understand - and they are not uneducated people - yet they think that their radios are special somehow and that they defy the laws of communications - which as far as I know has not changed much in the past 70 years...

When I try to explain to them that their communications is limited by the size of the radio and the length of the antenna on the radio - they don't seem to understand and they tell me that they do not want to buy a walkie talkie that is rated for 30 miles - because they don't want to talk that far.
I keep trying to explain to them that in the woods of Pennsylvania that they would be darn lucky to transmit 3 miles and that all it would do would be to help their radios transmit a little better between hunters and that it would not become a super transmitter where they can start their own little radio station with nothing more then a hand held walkie talkie.

If someone could be kind enough to post the link to the other reference - as per how the radio waves reacts to the hills / mountains - I would be most appreciative.
Thanks

The motorola T7200 and T7400 are TWO watts,not one watt if you didn't know? Not that it makes a big difference.

n9zas