JLeikhim

This is good news and not unexpected. Sent from my SM-T350 using Tapatalk

I would rather be obsessive about maximizing reject notch as T-R isolation is the main goal of a duplexer. If you can keep the insertion loss in spec and not excessive, fine, but insertion loss is an expected feature of a duplexer. There is no free lunch.

1) Use a Dremel tool with small radius to carefully carve a slot in the end of the screw shank, then back it out with a flat bladed screwdriver. 2) Drill a small hole into the screw shank and use an "easy-out" to back it out. https://en.wikipedia.org/wiki/Screw_extractor

Chris; There IS one option. Set up a simplex repeater using an Argent Data Systems ADS-SR1 connected to a third radio installed at a high location on your property. It will "Parrot" the messages which might be annoying, but can improve coverage. I suggest an FRS radio equipped with solar power to supply both the radio and the ADS-SR1. You want as much height as possible.

I wonder how those numbers compare with part 90 licenses? Sent from my SM-T350 using Tapatalk

Since you brought up the prohibition, it is now incumbent on you to back it up. Sent from my SM-T350 using Tapatalk

I don't see anywhere in the rules any prohibition of a simplex repeater. Unless something is expressly prohibited, it is permitted. Sent from my SM-T350 using Tapatalk

Are we sure it isn't a third harmonic problem with the Sheriffs transmitter? Well looky here: FRS Channel 11 : 467.6375 / 3 = 155.879 MHz 155.880000 (output) 158.95500 (Input) KNEP918 Sheriff Dispatch Custer County Law Dispatch Looks like either the Sheriff is the violation or the BaoFengShui GMRS V1 cannot tolerate all those powerful signals getting into it from the new base antenna. My money is on the BF GMRS V1 crapping itself.

In reading the rules, broadcasting is indeed prohibited, as is using radios while committing a violation of state and local laws. Whether there is a local violation here is a question. Sent from my SM-T350 using Tapatalk

I would be interested in knowing exactly what law is being violated if this is on FRS. Probably one of your neighbors. Sent from my SM-T350 using Tapatalk

Does the head unit have a USB charging point? Sent from my SM-T350 using Tapatalk

GMRS is part of the LMR world so the propogation document I would refer you to is EIA/TIA TSB88C or D. Radios in LMR typically comply with TIA603D as far as SINAD sensitivity, IM , spurious, and adjacent channel rejection . That document stipulates how LMR radios are tested and provides minimum standards. The "Common" Chinese brand radios do not comply with any industry standards thus a receiver spec of "-122 dBm " is meaningless in the real world where stronger out of band signals will swamp the receivers of cheap radios that lack adequate front end filtering. Sent from my SM-T350 using Tapatalk

The difference in PL sensitivity is interesting. It suggests the SINAD sensitivity of the original radio is a bit poor. Typically a PL decoder will open at 6 dB SINAD or weaker. The receiver probably lacks gain in the RF or AF circuitry. It could be a firmware difference as well. Sent from my SM-T350 using Tapatalk

To be politically correct and technically accurate. I call them Low Parts Count radios. What do you get for buying a $29.95 radio versus a $799.99 radio? Fewer parts. Sent from my SM-T350 using Tapatalk

Have you tried talking to and from a company issue radio? Is there any delay in that mode? This is a common problem with cheap Chinese radios. Users cannot get them to work reliably with other radios or repeaters. They may be totally out of tune or have a defect because they are not engineered to the standards that more expensive radios are. Then we have the programming using "Chirp" software which is intended for ham radio operators, who may or may not have technical savvy to sort out the potential problems. If they cannot, its not a problem because they are playing in the ham radio "sand box" not a business or public safety environment (hopefully). Frankly I am surprised your employer is letting you use your own radio on the job. Your company selected a vendor, that admittedly is offering some pretty low end stuff, but it is perhaps well sorted out by their technicians before putting into service. How did you get the frequencies and DPL? Did your employer hand you the information or did you monitor it off the air? If off the air you may have frequencies transposed or erroneous, the DPL may be the wrong one because cheap radios respond with multiple solutions, two or three of which are probably wrong.

100% WRONG. YOU NEED TO READ THE FCC grant I posted up above which is the actual certification. You are misreading the test report. It clearly says 10K2F3E. The GMRS authorized bandwidth is 20.0 KHz but the radio is not certified anywhere close to that emission, likely because the hardware (minimum parts count radio) won't get you to 20 KHz bandwidth. "Authorized" in the test report simply means what the rules cited will authorize, not what the radio can attain. Your contention is like saying the road has an 80 MPH speed limit and then saying that an 8 horsepower Chinese Changli electric vehicle meets the speed limit because it can cruise at 25 MPH. It may be legal, but you would be dumb to buy it. Look at the math for the MXT400 2 x modulation + 2 x Deviation (2 x 3000 Hz) = (2 x 2.1 KHz) = 10.2 KHz bandwidth. The radio can deviate only +/- 2.1 KHz A proper wide band radio can deviate +/- 5.0 KHz. MXT400 FCC Grant linked at post #8 See a "generous" 10K5F3E listed for that radio. https://forums.mygmrs.com/topic/2383-midland-mxt500/page-2 I have been doing this for 45 years so I can read and understand FCC equipment certifications.

Do the company radios transmit any preamble tones like MDC1200? No the power level should not make much difference. Sent from my SM-T350 using Tapatalk

If your modulation is weak, the radio to IP gateway may be slow to respond to your voice. Also there could be a problem with your DPL being decoded reliably. Have you compared performance with a company issued radio? Sent from my SM-T350 using Tapatalk

They could simply apply for a change to the FCC certification. Why haven't they? This covert software is probably just a placebo. Someone needs to actually put a radio on a HP8920B analyser and test the deviation and show results on youtube. Otherwise it has as much credibility as their stated mileage claims for their bubble pack walkie talkies . If someone wants to ship a radio so modified my way, I will test it and eat crow. Sent from my SM-T350 using Tapatalk

This is a good point. A lot of these cheap radios lack proper bandpass filtering for the receiver and when connected to a decent antenna all manner of out of band signals from broadcasters to NOAA ( notoriously excessive power transmitters) will sap the gain of the receiver RF gain stages and block the receiver from picking up weaker desired signals. The ISO-tee is a method of injecting a desired signal into the receiver from an RF signal generator and comparing its reception when the ISO-tee is terminated with an antenna versus a 50 ohm resistor load. Ideally there should be little change. If there is, you have interference due to either on channel noise or out of band signals getting past the receivers filtering, if any. Unfortunately much of the cheap radio equipment leave out the proper filtering relying on the user either having an inferior antenna, ignorance of the problem, or both. Sent from my SM-T350 using Tapatalk

The MXT275 and MXT400 are both narrow band radios. The cert Grant for the MXF275 is at this link. https://apps.fcc.gov/oetcf/tcb/reports/Tcb731GrantForm.cfm?mode=COPY&RequestTimeout=500&tcb_code=&application_id=vztA7%2FjO6CQIj5FkpBy3lQ%3D%3D&fcc_id=MMAMXT275 A proper GMRS wide band radio will have 16K0F3E or 20K0F3E emission designator, nothing smaller. Sent from my SM-T350 using Tapatalk

I guess that comment is directed to me since I seem to be the one most vocal about Midland's apparent refusal to be honest about this subject. Below is the FCC Grant (click thumbnail) for the MXT400. It is easily found on the FCC OET Equipment Certification database. The FCC grant is what matters. Regardless of what someone in Midland marketing has said, the MXT400 is certified as a narrow band radio. 10K5F3E is what the grant has as the modulation. That is somewhat worse than 11K3F3E which is what a narrow band is these days. A proper "wide band" radio complying fully with GMRS specs will have an emission designator of 16K0F3E or 20K0F3E. The rule sections 95.1771, 95.1773 and 95.1775 stipulate a 20 KHz BW and +/- 5.0 KHz deviation for the main (not interstitial) channels. If in fact the software distributed by Midland invokes a wide band emission from the MXT400 then it is doing so in conflict with the radios type certification. Something Midland could fix by having the lab Timco test the radio under that configuration, and if it passes, then apply for a permissive change. So far no one has produced any evidence that by setting the 25 KHz or 20 KHz bits in the software actually increases the modulation. If someone does this live on youtube with proper test equipment so no sleight of hand, then I will retract the part of my assertion that the radio does not do wide band. But it will remain un-certified. In the meantime the fact remains that folks buying a 40 or 50 watt Midland radio that delivers only 50% of the deviation permitted by GMRS rules, are getting an inferior product that has weak deviation and poor repeater CTCSS access. They might as well buy a cheaper, used, 25 watt Kenwood TK-840-1 which is certified for part 95, has wide band deviation and sounds better. I urge anyone shopping for a GMRS radio to look up the certification and grant on the FCC OET database for radios being considered. Most cheap Chinese radios also fail to deliver the modulation bandwidth permitted by FCC. Some have barely a 5 KHz BW. The FCC grant shows the power level as well as the emission bandwidth. I have no axe to grind with Midland other than this low deviation issue. I would love to buy their MXT275 micromobile remote radio for my wife's car. But instead she has a Kenwood.

From my ham license: Conditions: Pursuant to §309(h) of the Communications Act of 1934, as amended, 47 U.S.C. §309(h), this license is subject to the following conditions: This license shall not vest in the licensee any right to operate the station nor any right in the use of the frequencies designated in the license beyond the term thereof nor in any other manner than authorized herein. Neither the license nor the right granted thereunder shall be assigned or otherwise transferred in violation of the Communications Act of 1934, as amended. See 47 U.S.C. § 310(d). This license is subject in terms to the right of use or control conferred by §706 of the Communications Act of 1934, as amended. See 47 U.S.C. §606. That's just how licenses work. I have a "Virage" Go Kart license. It does not extend or allow me any rights beyond their track. It is no good for Formula 1 or to drive on public streets. Louis Hamilton has a Formula 1 license. He still needs a UK drivers license to drive to the supermarket. He can get a Virage go kart license for $3 like I did and zoom around a track for 5 minutes.

Not to mention that a lot of the cheap consumer radios don't fully utilize even the narrow band 11.5 KHz bandwidth. If you look closely at the FCC Certification Grants, you will see 10Kx or even lower emissions. Why? Because the radios are based on a simple chip and have few added parts to shape the modulation properly.

§95.385 RF exposure evaluation. (a) Personal Radio Services devices are subject to the radio frequency radiation exposure requirements specified in §§1.1307(b ), 2.1091 and 2.1093 of this chapter, as appropriate. (b ) FCC certification (see §95.335) of transmitter types that are “portable devices,” as defined in §2.1093(b ) of this chapter, and are designed to operate in certain Personal Radio Services, is subject to rules requiring radiofrequency radiation exposure routine evaluation pursuant to §§1.1307(b ) and 2.1093 of this chapter. See §§95.2385 and 95.2585.