marcspaz

My primary GMRS antenna is a Tram 1126B mounted with a Comet mount on the side of the hood. Works fantastic. In hilly/mountain terrain, I get between 2.5 to 8 miles (VA) mobile to mobile and in flatter, more open areas I can talk 25-30 miles radio to radio. I have no trouble reaching well built, well placed repeaters 35-40 miles away with 5 watts. I also have the Comet 2x4SR antenna. I am not impressed with the SWR on the 467 MHz frequencies. It's acceptable (note great) on the 462 MHz frequencies and all of the covered amateur bands, but he antenna was designed for a cross platform user with FRS/GMRS channels 01 through 7 and 15 through 22. The antenna isn't meant/designed for good SWR on channels 8 through 14 or the repeater inputs. I have always had Jeeps with either plastic or fabric roofs, so mounting it high has never been an option for me.

As far as I know, you can't listen on two radios at the same time AND be able to transmit on either of them, one at a time or otherwise. Even a switch won't make that possible unless you are using two switches to completely cut out the other listening radio before transmitting. Duplexers are frequency split and directional. So, that is off the table. Diplexers are also frequency split, but support two-way communications on the same frequency. However, each side of the split typically has a vast enough frequency split that two radios can't transmit and receive on the same frequency on both sides of the split. Most of the time, they are band splitters. One side being VHF and the other UHF or one side is VHF/UHF and the other is HF/MF. Some T splitters (which are very affordable), but not all, would allow you to receive on both radios at the same time. However, you can't transmit without destroying the other listening radio. So, that really only leaves a T connector and two auto-sensing or manual switches. Keep in mind that there will be a small amount insertion losses, but you are facing potentially high expense. Frankly, even using 2 high-end auto-sensing switches is risky... I wouldn't do it. Keep in mind, I don't know everything and I am not aware of every device or method out there. This is just from my experience and training. Someone else may have a better answer.

Most men I know have a general philosophy of "when all else fails, read the directions."

I didn't know there different subscriptions. Learn something new.

It doesn't help that the FCC flagged the GMRS manual as being for the amateur radio. I think people may be using that as a reference.

That's not for a KT8900D. The KT8900D is an amateur radio. Not a GMRS radio. From the manufacturer.... Dual Band: VHF and UHF / 144 / 430Mhz TX amateur band version: 144-146 MHz et 430-440 MHz RX: 87.5-108MHz, 136-174MHz, 400-480MHz, 220-260MHz and 350-390MHz The QYT KT-8900D covers RX and TX 144-146MHz and 430-440Mhz in analog FM mode with 25 watts (VHF) and 20 watts (UHF) and VFO button for channel or frequency change.

That radio isn't compatible with GMRS. As pointed out above, its a Ham radio, not a GMRS radio. It can be modified to work on GMRS, but there is no soft-mod. It requires a technician or someone technically skilled with the proper tools to both add and remove some components from the main board. Once that is done, it needs to be reprogrammed. Given it costs about $45-$50 to do the mod (assuming you already have all the tools) and its only an $80 radio... almost no one does it. I would recommend you just buy a GMRS radio.

Technically, its a rule violation, not a law violation... but to answer your question, no, you are not authorized to have a simplex conversation on those input frequencies.

I agree... 50 watts is not needed. If you had not made a purchase yet and it fell into the "nice to have" category, that would be fine, but there is very little range difference between 15-20 watts and 50 watts. You probably wouldn't notice in the hills and mountainous areas. People who benefit from the additional power will be those who are out in open areas (water, desert, flat country/farm lands). Especially if they are using a large tower or have an elevation advantage and are trying to communicate with a party with a similar setup. As mentioned by @gortex2 if you are wheeling with people who are using handhelds, it won't matter anyway.

Correct. Being galvanically coupled to the HT is extremely unlikely. Galvanism must occur via direct contact with a conductive case or conductor on the case. Most HT's are made out of non-conductive plastics and other non-conductive materials. Due to the air-gap between the antenna ground inside the radio and the operator, combined with the resistance of the material of the body of the radio, the only way a human body can become part of the antenna system (which is dependent on the radio design and operating frequency) is via capacitive coupling. In a vast majority of VHF and UHF radios, the human body is in obstructive obstacle in the radiation path, rather than a useful part of the antenna system. Yeah, I got nothing on that one. LOL

I get it.

Agreed. For the best, most accurate results, an impedance bridge is the correct method. That is usually only worth it for someone designing a radio or antenna. For the average user, the labor and risk are to high. I also agree with this. The human body and the radio are part of a capacitive coupled counterpoise. Ehh... that can be handy, but it doesn't tell us if the antenna is balanced with the transmitter. I actually have an antenna analyzer that emulates having the antenna on an HT. You can rely on using a capacitive coupled counterpoise (by holding the meter) or you can add a wire to use as a counterpoise. The meter tells me the resonant frequency and the SWR of the antenna at that frequency. Most antennas I have tested have a 78 ohm impedance for their advertised center frequency. Some as low as 73 Ohms.... so a 1.5:1 SWR. The worst I have seen was 250 ohms about 5:1.

So, I usually understand what you are saying and typically agree with you on technical issues, but I am seriously missing something here. Are you implying that there is no way to measure the SWR of an antenna that screws to the top of the handheld radio? Or are you implying there is no way to to measure the SWR while the antenna is on the handheld? Or are you implying some other type of measurement can't be done?

@kidphc I have one of the inexpensive surecom units and it is extremely close in accuracy to my very expensive commercial meters. I would use it with confidence.

Why would you say this?

I fell for the advertising for the Abbree antenna too. I kept it because I am a Ham and can use it on amateur radio frequencies. On the GMRS 462 MHz frequencies, the SWR is 2.6:1 and on the 467 MHz frequencies, the SWR is 3.1:1. I definitely would not use it for GMRS. It will perform terribly and with prolonged use on the repeaters, you may damage your radio.

Is this while mobile or are you walking around/standing outside? Just my opinion, but I doubt any other antenna is going to help, even if it is advertised as having more gain. Every 3 dB is one signal unit. If you are on the very edge of the repeater where you are just barely out of range, you need to increase your effective radiated power to impact the receiver on the repeater 3 signal units to "possibly" be heard and understood. That is gain of anywhere from 9 to 12 dB gain... equal to about 50 watts of radiated power from your handheld... and that is assuming you are just barely out of range. It's not gonna happen. If those "dead spots" are due to terrain blocking your signal, being too far below the line of sight horizon, radio frequency interference, heavy woods or several buildings (or any number of other issues)... you won't be able to boost the signal enough.

I've mentioned this before, I think experiences are regional. I'm with several ARES teams and one of them is extremely active with supporting local, state, Federal and DOD with communications. I can tell you right now that, even with all of there high-end communications gear that have some people looking down their nose... every time there is a mass municipality response, no one can talk to each other directly. The government has been trying to fix this problem for 40 years and it's still a problem. Then, my team recently supported a DOD event for the US Marine Corps. There where several Marine outposts and checkpoints that lost 100% communications with command. If it wasn't for the amateurs embedded with them, it would have been hours before a communications path was restored... some locations had no idea their radios weren't working. Command later told me specifically that the reason we are invited to all of these events is because we regularly move more traffic, faster and with more accuracy than the Marines do. And we regularly get the same types of feedback from the local and state agencies as well. I think it sucks that some of you have bad experiences, but it's not everywhere and Ham radio certainly isn't a dead or an antiquated EmComm resource.

@gman1971 it is pretty awesome. I'll see if I can find someone to chat with and record it so you can hear it. I'll shoot a video.

No channels are reserved for anything except for repeater input frequencies being reserved for repeater inputs. Even that has some exceptions. § 95.1731 Permissible GMRS uses. The operator of a GMRS station may use that station for two-way plain language voice communications with other GMRS stations and with FRS units concerning personal or business activities. (a) Emergency communications. Any GMRS channel may be used for emergency communications or for traveler assistance. Operators of GMRS stations must, at all times and on all channels, give priority to emergency communications § 95.1763 GMRS channels. (c) 467 MHz main channels. Only mobile, hand-held portable, control and fixed stations may transmit on these 8 channels. Mobile, hand-held portable and control stations may transmit on these channels only when communicating through a repeater station or making brief test transmissions in accordance with § 95.319(c).

In 2018 and 2019 I was addicted to 10m FM long distance contacts. Talked to somebody on an FM repeater in NY state. The repeater was full-quiet on my receive and the other guy (who was local to the repeater) said I was full-quiet into the repeater. Another person I talked to in Texas mobile to mobile. We were 60dB over S9 both ways.. it was like we were parked next to each other. Stuff like that is a blast. It's part of what made me upgrade to a General... the solar minimum rolled in and I still wanted to talk.

Good deal on the Flagpole climb... its a fun spot for sure. I would love to head out the Rausch Creek with you all... but I have family that will be here then. Hit me up on FB in either TKO Jeepers or Evolution Jeep Alliance. TKO is local to Prince William County and EJA is local to Rausch and AOAA. We can figure something out. Always looking for someone to wheel with.

The temp on the radio can get a little spicy under heavy use, but as long as you don't put it in front of the heat vent, you should be fine. Checked out the Jeep on IG... looking sharp! Since you are in VA and some of those pics are from Flagpole, I guess you recognized where my pics came from. LOL Once you have your license, come on back and register for the forum. There is a lot of good information in the private sections (need an account to see) and the folks here are very talented if you need/want any technical help.

I did not know that... That is a very handy piece of info and may be a good compromise. Kiel / OP... definitely checkout this YouTube channel. I think this may be the "Hobo" in question... https://www.youtube.com/c/NotaRubiconProductions <Spaz giggles in radio geek>

Glad the information helped. And yes, you are correct. Out of the box, hookup power and and antenna and just start talking. Out of the box, it is completely compatible with all FRS and GMRS radios, with no need to adjust/change anything. I had a 2016 JKUR before the JTR, it could be a massive pain in the six to put the windshield down. Pull the 2 wiper blades. Pull the corner caps (4 bolts each side). Then you have to remove the two roll bar segments that connect the windshield to the 4-point roll bar (6 bolts each side). So, 22 bolts/nuts to remove. The goo thing was, if I was going to fold the windshield down, I would do it for days or even weeks at a time. When I needed the glass in place for driving, I would push the windshield up, screw the corner caps down with forward pressure on the corner cap bolts and zing the bolts down. Then, when you close the doors and latch the soft top, the windshield is very stable. It shakes a little on hard bumps, but it was worth it to now put everything back together, because it does take a long time to do.