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Ah no. When you see gain spec of 9dbi that’s a gain over an isotropic antenna that doesn’t exist. It’s for reference only. What you really want is a gain spec over a dipole, or a simple quarter wave, which is the smallest antenna that can be physically built. The difference in gain between the two is 2.15db. So the real practical gain is now 6.15db. But wait, we’er not done yet! Now you have to figure in your coax loss. For a typical run of 75 feet of LMR400 at 450MHz, close enough to the GMRS band at 462 to 467, the loss is another 2.03db. So your real gain is around 4.82db, which is a factor of 3.03 increase. For 5 watts in it looks like you have an effective radiated power of 15.17 watts.

I did not see the posts in question. However, I am very surprised to hear about snarky criticism on this forum. This is probably the best behaved online group or forum I have ever participated in. Yes, I have seen a couple of disagreements, but even then, the discussion was always fact based and never mean spirited. Is it possible you are being a little sensitive? That has actually happened before, and when the issue was noted and people explained their views and why they had posted them, the problems vanished. And, on a few rare occasions, the criticism of the poster was justified, behavior changed and we all moved on. Just my 2¢ worth.

One point not mentioned much are the gain figures work both ways. That is on transmission and reception. It pays to optimize the losses. A 5 watt radio likely is about as sensitive as a 40 to 50 watt one. You can run into cases where spending more money on a higher power radio to make up for the power loss but it does nothing to increase the receive signal strength. If you can’t hear the other station it doesn’t matter how much power you run. This could be the difference between using a 5 watt handheld with a roof mount antenna, or spending a lot more money on a high power mobile radio. I think enough information is here where choices can be made that fit budget and physical installation requirements. There shouldn’t be any really big surprises how the final system will perform.

Did I miss something? Seems like civil responses here.

No disagreement. Only a reminder to readers of a point @Jones made earlier. There is a place for thin cables, particularly in a mobile environment. Also, in a case where the radio is at a window and the antenna line goes out the window and a few feet up to an antenna. Noted in these forums before, but always important to keep in mind: Perfect is the enemy of good. If someone deployed 50 feet of RG58 to their antenna and can reach all the repeaters and mobiles they want, then that is probably a good time to stop.

No. I just received it and a power supply to run it at my home. I have been researching the operating rules and antenna options before setting it up. There is also RG-58X low loss available, also. I bought a ground plane kit to use with the 3dB antenna it came with and hope to get a Deep Recon G1 kit for "bug out", etc.i will mount the antenna on a camera tripod for that operation. I was trying to find specs for the transmit power on lo and mid settings.

I’ll leave that as an exercise for the student to figure out the system gain as they instructor used to say.

It's worse than that, he said he will be using Rg58u.

Not necessarily. The only repeater capable blister pack radios I’m aware of are the Motorola MR-355R (of which I own several), MR-356R, MS-350R, and MS-355R, as well as the Liberty 500. Radios such as the MR-350R, MR-360R, etc. are not repeater capable in spite of the R at the end of their nomenclature. Personally, they’re mostly useless to me. ~1.3W PEP, narrow band, can’t do non-standard DCS octals or split tones (both of which are used on Front Range GMRS repeaters). Now I said mostly useless, not wholly. When in scan mode, if a signal is picked up, it’ll immediately identify which CTCSS or DCS tone is in use (if it’s one which is on the standardized list). If it’s a small and pretty standardized list of frequencies they’d be using, maybe a 8 or 16 channel radio such as a TK-360, HT750… maybe even a BF-888S… might be a better way to go if split tones and/or non-standard octals are something you’d encounter.