Garmin Rino 140

[+aka Monkey]

So Garmin has recently come out with the Rino 130 with all its sensor-laden goodness, and they've also come out with the 60cs, with its beautiful color screen. So how long before we see the Rino 140, with a color screen?

 

I'd love to upgrade my GPS, and I really like to 60cs, but the radio features on the Rino are handy (especially the weather radio capabilitie on the new 130). I already have a Rino 110 and 120, so getting a 130 just makes sense... but a color screen with 30 hours of battery life and 56 MB of memory would be WONDERFUL.

 

dadgum you, Garmin!

[+leatherman]

Hear, hear!

 

 

:spelling go figure

Edited January 4, 2004 by leatherman

[+lnk3d]

BUMP

 

Hooo Yaaaa!!! Rino 140 w/ Color Screen, and how about some better wattage out of the FRS and GRMS Transmissions ( Can get a midland g-300m which is smaller than a Rino and is 3 Watts! )

[+leatherman]

BUMP

 

Hooo Yaaaa!!! Rino 140 w/ Color Screen, and how about some better wattage out of the FRS and GRMS Transmissions ( Can get a midland g-300m which is smaller than a Rino and is 3 Watts! )

Pumping out more wattage doesn't make a better radio. I bet my Motorola T7200 sounds much better than the Midland, and it only has 2W.

 

In fact every radio performs differently. The 2W cobras suck. Might as well be 1/2W FRS radios.

 

I've tested 3 different Motorolas. They all perform and sound differently. Wattage didn't matter. The difference between 1W and 2W is less than one mile more distance. Three watts can't be much different.

 

The Rino has waterproofing. That severely effects the sound quality.

[kb9nvh]

In general it takes 10 times increase in transmitter power to double your range.

 

So if a 1 watt transmitter/reciever combo can transmit 1 mile max then for them to get to two miles the transmitter would have to up its power by 10 times (10 watts). Power output on these radios is a minor concern. Just think of the batteries you would use up running 10watts instead of 1 watt just to double your transmitting distance.

 

Transmission range is really much more complicated than that.

Transmitter distance measurements are subjective. How far you can transmit depends much on how sensitive your recieving station is and how much "noise" is present on your frequency and mostly "line of sight" considerations. What trees, hills, buildings are in your way (at FRS frequencies especially).

[+leatherman]

Just think of the batteries you would use up running 10watts instead of 1 watt just to double your transmitting distance.

True, true....

 

Most 4W handheld CB radios use six to ten batteries. They can burn through those pretty quick too.

[+GeckoGeek]

In general it takes 10 times increase in transmitter power to double your range.

Really? I would have though that it would take 4 times the power to double the distance based on the idea that light intensity will follows the inverse square law.

 

You can easily create a thought experiment to show that. Take a projector that produces a 10' x 10' image at 20'. Now move the screen to 40'. The picture will now be 20' x 20', so the same amount of light is now covering 4 times the area (400 sq ft vs 100 sq ft.) So the light intensity (measured as candle power per square foot) is now 1/4 of what it was before.

 

I'd think radio waves would follow a similar pattern.

[+Right Wing Wacko]

In general it takes 10 times increase in transmitter power to double your range.

Really? I would have though that it would take 4 times the power to double the distance based on the idea that light intensity will follows the inverse square law.

 

You can easily create a thought experiment to show that. Take a projector that produces a 10' x 10' image at 20'. Now move the screen to 40'. The picture will now be 20' x 20', so the same amount of light is now covering 4 times the area (400 sq ft vs 100 sq ft.) So the light intensity (measured as candle power per square foot) is now 1/4 of what it was before.

 

I'd think radio waves would follow a similar pattern.

But the radio is not just transmitting in ONE direction. Radio waves are not two dimensional, they go in all three dimensions. You have a sphere since signals are going in all directions. including being absorbed into ground.

 

The formulas for calculation of the area of a sphere are somewhat complicated but can be arrived at with r^N (pi^(N/2))/((N/2)!) (Notice the FACTORIAL operation.

[+GeckoGeek]

The formulas for calculation of the area of a sphere are somewhat complicated but can be arrived at with r^N (pi^(N/2))/((N/2)!) (Notice the FACTORIAL operation.

Is that for the AREA of a sphere or the VOLUME of a sphere? We're interested in the surface area as we're measuring the strength of the signal's wavefront.

 

A quick google showed this page for the surface area of a sphere, and it shows that the area grows as a square of the radius which is what I originally proposed.

[+slinger91]

I know, don't quit my day job. But, maybe Garmin is watching.

 

[+benjamin921]

Garmin just released info on this very unit.

 

 

 

 

 

 

 

 

 

 

 

 

Haha, J/K. This would be sweet and the logical next step. In the mean time it looks like the 60CS will have to do.

[kb9nvh]

In general it takes 10 times increase in transmitter power to double your range.

Really?  I would have though that it would take 4 times the power to double the distance based on the idea that light intensity will follows the inverse square law.

 

You may be right....

 

My first message was just restating a old "rule of thumb" that I had logged away "upstairs". Doing a little review the formula is P=1/(x**2)

 

So indeed this would seem to indicate the 4 times rule (not 10 times).

 

I'm at work now so can'tresearch this further now, However, reciever sensitivity is measured in microvolts and so maybe the discrepcancy here is the conversion from "power" seen at the reciever to "volts" at the reciever. Not sure at the moment. Maybe we should post this in the amateur section and get some more "enlightened" responses.

 

In any case, I appologise for opening my mouth before I enguaged my brain...*grin* (I'm sure this is the last time that will happen..) hahaha

 

 

 

You may be right....

 

My first message was just restating a old "rule of thumb" that I had logged away "upstairs". Doing a little review the formula is P=1/(x**2)

 

So indeed this would seem to indicate the 4 times rule (not 10 times).

 

I'm at work now so can'tresearch this further now, However, reciever sensitivity is measured in microvolts and so maybe the discrepcancy here is the conversion from "power" seen at the reciever to "volts" at the reciever. Not sure at the moment. Maybe we should post this in the amateur section and get some more "enlightened" responses.

 

In any case, I appologise for opening my mouth before I enguaged my brain...*grin* (I'm sure this is the last time that will happen..) hahaha

[+GeckoGeek]

reciever sensitivity is measured in microvolts and so maybe the discrepcancy here is the conversion from "power" seen at the reciever to "volts" at the reciever. Not sure at the moment. Maybe we should post this in the amateur section and get some more "enlightened" responses.

You may be right - I may be crazy.... Oops... I'll stop singing now....

 

Hmmmm. Well, I was looking at the other angle - what would it take to create the same "brightness" at the receiver. I assumed it would take 4 the power to create the same brightness at twice the distance, but if it takes 4 the voltage instead then it would also take 4 times the current to feed the transmitting antenna and we'd be left with needing 16 times the power - a square of a square. But that doesn't sound like the right answer ....Four times the power for double the distance sounds more reasonable.

[+Sidewinder_6]

Just thought I would share an interesting experience with FRS radios. While I was in Kosovo, we operated in the mountains and used FRS radios for section communications. We know that they aren't secure but being 18 miles away from Camp Bondsteel we didn't think the head shed would hear us either. We were wrong The morning after we set up our position we started hearing someone we thought sounded like our 1SG giving instructions to one of our maintenance people. We figured that there was a convoy on their way up to see us. After talking with him on FRS, he was still at CBS (18 straight, unobstructed miles away - measure on a map). Just about any time that we had line of sight between us and CBS, we could hear FRS radios very clearly. As long as we didn't have any mountians between us, we didn't need OE-254's (long antennas) either.

[LowranceTracker1]

Indiana Cojones:

 

You have that kind of cash to just buy any gps that comes along. Must be nice!

 

I had a hard enough time convincing the wife for the only one I own.

 

[kb9nvh]

reciever sensitivity is measured in microvolts and so maybe the discrepcancy here is the conversion from "power" seen at the reciever to "volts" at the reciever.  Not sure at the moment.  Maybe we should post this in the amateur section and get some more "enlightened" responses.

You may be right - I may be crazy.... Oops... I'll stop singing now....

 

Hmmmm. Well, I was looking at the other angle - what would it take to create the same "brightness" at the receiver. I assumed it would take 4 the power to create the same brightness at twice the distance, but if it takes 4 the voltage instead then it would also take 4 times the current to feed the transmitting antenna and we'd be left with needing 16 times the power - a square of a square. But that doesn't sound like the right answer ....Four times the power for double the distance sounds more reasonable.

Yeah, I was thinking Db like

 

P1/P2=10log(V2*I2/V1*I1)

 

But I dont think thats what we want cause we're not talking Db's

 

I promise I'll look this up soon and get to the bottom of it...I do remember that rule of thumb of 10times output power to double your signal at the radio...Just can't argue it just yet....

 

Stay Tuned!!!

[+GeckoGeek]

I do remember that rule of thumb of 10times output power to double your signal at the radio.

10 times out is 10dB. I'm not sure what that is in S-units. A quick google suggests 6 dB/S-unit, so 10dB is around 2 S-units.

 

Now I do know that because of the human ear's logarithmic response to sound levels it take about 10dB it make something sound twice as loud. So it takes a 200W PA system to sound twice as loud as a 20W PA. In fact that's where the unit came from. One "bell" is twice/half the perceived sound level. Details and History.

[+aka Monkey]

Indiana Cojones:

 

You have that kind of cash to just buy any gps that comes along. Must be nice!

 

I had a hard enough time convincing the wife for the only one I own.

 

Well, not really. The only reason I'm considering the 60C right now is because I've been selling a bunch of stuff on eBay, so I have almost enough money to pay for it.

 

Plus, I don't drink coffee, I don't smoke, I don't drink, I don't even have cable TV... that ends up saving me quite a bit of money every month compared to most of the people I know.

 

I suppose it's all about priorities. For me, Geocaching gets me outside and getting exercise. If a GPS helps me do that, it's a justifiable expense.

Edited January 8, 2004 by Indiana Cojones

[kb9nvh]

Here's a range chart That I looked up....showing powers and such

 

This is taken from this page Simpletons guide to radio

 

[+GeckoGeek]

Here's a range chart That I looked up....showing powers and such

Wow. If I'm reading that right, it looks like going from 5W @ 1000' tower to 100W on the same tower would only get you 50% more distance on the 450 band. (GMRS is around 440 - 450).

 

One problem with this chart is that it's taking into consideration the curvature of the earth. Probably not a concern at the shorter distances to be expected when you're looking at lower powered devices.