Repeater radius versus HT Radius

[Ziggidy]

Considering any interference may be a factor, on paper what is reality?  

Example.  A local repeater says it has a 40 mile radius. My HT has, let's say 1 mile radius.  Will my HT need to be within that 40 mile radius of the repeater or does my HT need to be within 1 mile from the repeater for best communication?

It's confusing to me how I can communicate with one repeater within Indy but one just as close I cannot; all tones being correct (at least I believe so).  I am in Hendricks County and reach 1 repeater but none other.  I am using the member tones provided by MidwestGMRS.

Thoughts?

[kidphc]

Repeater distances, are at best a guestimate by the owner.

Obstructions will be the main cause. If you can climb on to the roof, and see the antenna of the repeater you have a good chance.

I have been up almost 50 stories locally and am surprised by the amount of antennas I can see. But the rolling hills here tell me there are tons of rf shadows.

Plus some repeaters, transmit better than the hear and vice versa.

Sent from my SM-S901U using Tapatalk

[amaff]

"It depends"
None of them, unless they're are on open, dead flat ground, will have a horizon that's a circle.

The one further away may have a better, taller antenna, more sensitive hardware, or fewer obstructions.

Or it's possible the one close by is down for some reason (maintenance, equipment failure, etc)

[BoxCar]

The one key factor in distance for radio is the height of the antenna. Higher antennas clear more obstacles and have a greater distance to the horizon. The next factor is the output power from the antenna as some antennas have a gain factor that negates losses in the coax between the radio and antenna.

[WRYZ926]

3 hours ago, BoxCar said:

The one key factor in distance for radio is the height of the antenna. Higher antennas clear more obstacles and have a greater distance to the horizon. The next factor is the output power from the antenna as some antennas have a gain factor that negates losses in the coax between the radio and antenna.

This is very true.

I live 21.5 miles away from our repeater sight. The 2m and 70cm repeater antennas are at 900 feet while the GMRS repeater antennas are at 400 feet. It is very hit or miss if I can get into the 70cm and GMRS repeaters from my house using an HT with rubber duck antenna. Yet I can use my two mobile radios on low power with a Comet 2x4SR antenna or my base station on low with the Comet CA-712EFC (mounted on the house roof) and get into the repeaters every time. Both the Wouxun KG-1000G and KG-XS20G are around 5 watts on low power. 

It is the same with trying to get into the 70cm repeater as it is with the GMRS repeater.

What makes a difference is the height of the antennas on my vehicles and home versus a rubber duck antenna. Now there is a bit of static when using the mobile/base radios on low power but I am still able to understand others and they can hear me clearly. Bumping up to medium or high power clears up the static.

Any antenna with at least 6 dBi (4dBm) of gain or higher will definitely help overcome any cable loss. Just make sure you are using the correct coax for UHF frequencies such as LMR400 or equivalent. G8 and RG8X are best suited for HF frequencies and have more loss on VHF and UHF frequencies.

[LeoG]

I can regularly hit a repeater 17 miles away with my TD-H3 HT that outputs 4.7 watts.  My voice volume is definitely soft when receiving on another HT in the within the same couple of towns still 12-17 miles away from the repeater.  The repeater is 1000+ ft up on a mountain and I'm 62ft above sea level.

Yet going HT to HT is usually limited to about 2 miles or less depending on what is in the way.

 

I have another repeater that is 21 miles away on another mountain and that one is iffy when I can get in contact with it.  Quieting isn't good but I'm still understandable.  I pretty much figure that's the limit of range for my little HTs