mbrun

FPP allows use of the standard +5MHz offset only. No other option available. You would need the software to do non-standard stuff.


Michael
WRHS965
KE8PLM

Good Day DownEastNC.

An antenna that has been optimized for GMRS frequencies will equally well for both transmit and receive. It will receive almost all other frequencies too, but it will not perform as well as an antenna that has been optimized for the other frequency(s) of concern.

The same can be said about a dual-band amateur radio antenna. Said antenna will perform best on the frequencies for which it has been designed/optimized (2m & 70cm). A few designs might have characteristics that make it acceptable for use also on GMRS but they will have lesser performance than a similar design optimized for GMRS.

So, the bottom line is YES. If you are using an antenna optimized for amateur frequencies you are indeed compromising GMRS communications. Whether that compromise is material to you is totally up to you.

I own both GMRS and amateur radios and antenna. Where weak stations are concerned, the GMRS multi-band radio used with the GMRS antenna receives GMRS signals more strongly than its amateur radio antenna and receiver. The reverse is also true. If I switch the GMRS radio to receive VHF frequencies, the amateur radio receives the signals more strongly. In both cases this is due to what the antenna is are optimized for.


Michael
WRHS965
KE8PLM

There is nothing inherently wrong with running the coax inside the pole, be it a metal or fiberglass mast. It is really no different than running the feed line in conduit. It could make for a nice looking installation.

Be aware that if the mast is collapsible you must have provisions at the bottom to evacuate excess feed-line when mast is collapsing. Different considerations are necessary if it is a tilt over.


Michael
WRHS965
KE8PLM

If the cables are poorly shielded, yes, the potential exists that when transmitting you could get some leakage into your over-the-air antenna coax. I would suggest RG-6 or RG-11 quad-shielded coax for your TV coax, the same high-grade stuff that the cable TV utility should be using as drop cable to your home.

The bigger issue you may have to contend with if you are thinking of putting both antennas on the same mast, is actually over-the-air leakage from your GMRS transmitter getting into your antenna. If a family member is not watching TV and/or you are not DVRing a show it may not be an issue. I have been known to mess up a recording or two while talking on the radio at my place.


Michael
WRHS965
KE8PLM

There is nothing inherently wrong with running the coax inside the pole, be it a metal or fiberglass mast. It is really no different than running the feed line in conduit. It could make for a nice looking installation.

Be aware that if the mast is collapsible you must have provisions at the bottom to evacuate excess feed-line when mast is collapsing. Different considerations are necessary if it is a tilt over.


Michael
WRHS965
KE8PLM

Your results sound completely normal for two radios operating simplex, antennas at 4-7’ AGL, and with loads of obstructions.

Midland’s lure of “38-Mile Range” is worse that saying “You too could win the lottery”. In the real world you are more likely to win the power-ball lottery 6 times before you would ever experience 38-mile range with their walkie talkies.

Obstructions are the enemy of range in radio communications. Never underestimate how much they negatively effect range and don’t accept any statements to the contrary.

Two GMRS handhelds will have a range of 6-miles if used on row boats over smooth water until the earth (water) becomes the obstruction and the signal is lost. That assumes both people are standing in the boat and holding radios at 6 feet AWL. If both people now sit in the boat, range will drop to about 3 miles until the earth becomes the obstacle again. Do an internet search on ‘Radio Horizon’ to see how this works. Also, here is a simple calculator to see what your best case scenario is: https://www.everythingrf.com/rf-calculators/line-of-sight-calculator.

As you will learn, the earth is an obstacle that blocks your signal quite dramatically. If there are hills between the two antennas, same thing. Hills are an earth obstacle. Now, if you go into a heavily treed area, or an urban area with lots of buildings everyone of these attenuates your signal to some degree too. All of these add up to reduce your range further. Mix distance, hills and other obstacles and range is squashed.

You will hear over and over phrases such as “Height is might”, “Height is King” and “Height is everything”. This is true for a couple of reasons. First, as each antenna goes up in elevation the radio horizon gets further and further way, so your theoretical maximum range on earth increases. Second, when you raise the antennas up, often the number and density of obstacles between the antennas drops too so your real-world range increases.

My simplex HT to HT range and HT to Mobile ranges mimics yours. However, when I use mobile to base communications with base antenna at 40’ I loose communications at around 4 miles. When I raise it to 56’ I loose all communications around 8 miles. Yet with both my base and mobile rights I can communicate with repeaters 22-50 miles away because the repeater antennas are so much higher than mine are. Higher antennas mean fewer obstacles, thus increased range.

Hope this helps


Michael
WRHS965
KE8PLM