SteveShannon

Neither Yaesu nor Icom have DMR modes. Yaesu has their own proprietary digital mode C4FM. No other brands use it. Icom uses D-STAR, a digital mode created by the Japanese Amateur Radio Society. Kenwood also makes radios for D-STAR. DMR is a different digital mode based on a format that was developed in Europe. Several companies make radios for DMR, including some of the inexpensive radios from China.

But I’d like to try and explain it in my words as well. The human ear has the ability to hear over a spread of frequencies from about 10-20 Hz on up to 15,000 Hz or even up to almost 20,000 Hz. High frequencies become more difficult to hear as you get older or suffer hearing loss. So that’s a bandwidth of say 20 Hz to 15,000 Hz or 14980 Hz. Speech can be pretty accurately reproduced in a much narrower bandwidth, but there’s still some information at the higher frequencies that help you discern different sounds, such as an ‘f’ sound from a “th” sound or even an ‘s’ sound. Now imagine if someone applied a band pass filter that starts at 300 Hz and ends at 6000 Hz. That’s narrowband. Compare that to a filter that allows 300-12500 Hz bandwidth. More sound information that can be encoded in that bandwidth. A wideband signal received by a narrowband receiver has to throw some of the information away, making the sound quality less, even though there’s more signal than it knows how to handle. A narrowband radio encodes less information but a wideband receiver receiving that information ends up a partially empty channel, which can sound weaker. But narrowband sounds okay when both ends are set to narrowband and wideband sounds incrementally better when both ends are set to wideband.

No problem. Here’s a video that addresses your question:

Shortwave? I don’t know what you mean by that. Are you talking about narrowband versus wideband?

Welcome!

I’m not sure I understand the question so I’ll try to bracket it with enough information to answer your question. Please feel free to correct me if I have misunderstood. If you are licensed for GMRS and you have received permission to use a repeater, then you can use that repeater. That’s true of any GMRS repeater. If your call sign is WRVL295, you are required to use that call sign when using any GMRS repeater. You identify yourself at the beginning and end of a conversation and at least every 15 minutes if it’s a long conversation. Don’t let that scare you. Any reasonable effort is probably good enough. Some people never ID and as far as I know nobody has ever gone to jail or even been fined for it. I tend to use my call sign too frequently. There’s no need for that either. I suspect it’s an irritant to other parties but they’ve all been really nice so far. ?

Cut the beginning off and replace it! ?

It could be because of that but it could also be because moisture has entered your coax cables at the connectors. Unfortunately once that happens the best thing to do is cut the end off and replace it.

Great example! Thanks!

Unless the gain of the antenna and the height combine to create poor reception area near the ground close to the antenna.

That does help! Thanks!

There is no set limit specifically for GMRS HTs as far as I can tell. They might inherit the 50 watt limit of mobile stations. But I agree with @KAF6045that SAR exposure limits would create a practical limit. In reading through an ARRL article about exposure limits, 5.3 (I think) watts is the calculated max power for a 70 cm handheld in order to maintain a safe exposure level.

Rather than using the screen, it’s much easier for me (with my NanoVNA) to use the PC based software (VNASaver). The screens are separate and the controls seem easier and more intuitive to use, at least for me. I absolutely agree that you must turn off all the displays that you don’t need, like the Smith chart, etc. Also, keep the bandwidth as narrow as possible. Those jumbled mess traces with sharp inflections and straight nearly vertical traces are typical when viewing too much bandwidth at a time. They’re a product of the fact that you have relatively few points (501 in your case it appears) being displayed, so the VNA simply draws straight lines between them. Viewing all the way from 462 to 468 MHz is much wider than you want. Instead, limit the width to 500KHz above and below the frequency you’re concentrating on. Depending on what you’re measuring that may even be unnecessarily wide. Good luck!

I think you’re probably right.

No, you don’t have to program a receive tone. If you leave it blank you receive everything transmitted on that frequency. I usually recommend leaving the receive tone empty until everything else is working.

I agree that there seems to be a section missing, but you’re wrong in your interpretation. 95.1767 doesn’t enable station types; it creates power limitations, and it neglected to establish limits for handhelds on the main channels, unless handhelds are covered as a subset of mobile stations, which isn’t consistent with how handhelds are listed in the other sections in 95.1767. The section on channels (95.1763? I’m away from the computer) is where station types are allowed on specific channels. Handhelds are listed there for the main channels, as I recall.

To make it easier to discuss, rather than a screenshot here are the regulations: Each regulation only means what it says, nothing more and nothing less. The limitation 95.1767(b) for the 462 interstitial channels, only applies to stations transmitting on the interstitial 462 channels. Likewise, limitation 95.1767(c) only applies to stations transmitting on the 467 interstitial channels. Nothing about those limits extends to the other two sets of frequencies (462 MHz main and 467 MHz main). Rules just are not written like that. Neither does the lack of a listing for a power limit for a Hand-held Portable cause the lower limits listed in 95.1767(b) to apply to 95.1767(a)(1). If it did that would be very tricky to determine whether to use the 0.5 w ERP limit of 95.1767(c) or the 5 w ERP limit of 95.1767(b). The fact is, no output power is specified for hand-held portable stations in 95.1767(a) unless you consider a hand-held portable as a subset of the mobile category, in which case 95.1767(a)(1) applies, limiting a hand-held portable to the same limit as a mobile. To me that doesn't seem right. Now therre may be a higher level regulation somewhere that limits ALL hand-held transcievers to a 5 watt limit; I just don't know. The definition of a Hand-held Portable may support that. From Subpart A: Hand-held portable unit. A physically small mobile station that can be operated while being held in the operator's hand. So, I still haven't seen a rule or regulation in part 95E that limits the output power (which is not the same as ERP) of a hand-held portable in the GMRS service to 5 watts. I'm convinced I'm simply missing something, but the explanation you propose doesn't seem right to me.

Re the first question on small coax: Because it’s cheap and they’re relatively short cables.

I believe that's probably the case, but I'm having trouble trying to find something in the regulations that limits handheld portable radios to 5 watts for GMRS. I know that for the 462 interstitial channels there's a limit (as quoted below), but like I say, I'm having trouble finding the part of the regulations that limits all GMRS handhelds to 5w.: 462 MHz interstitial channels. The effective radiated power (ERP) of mobile, hand-held portable and base stations transmitting on the 462 MHz interstitial channels must not exceed 5 Watts.

I dealt with them in the early 2000s. Their stock went from $4 to $44 and then they were acquired. Although their CAD-CAM market share disappeared their Utility AM-FM business still does well. That’s the system I worked on.

I agree with KAF6045; make sure you know how to sweep the antenna first and that you see something that makes sense to you. Then sweep the antenna using the other port on the analyzer to make sure you're seeing the same results on both. Only after you have confidence in the analyzer and your ability to analyze an antenna will you feel comfortable performing a two port analysis of a filter or one side of the duplexer.

The most common type of PL tone is also called CTCSS. There’s also DCS To determine it you ask a repeater owner or you can scan for it with some devices.

I was project manager and programmer on an Intergraph FRAMME system between 1999 and 2005. Ours was PC based but I spent many hours working with folks in Huntsville that you might have known.

I see what you did there … ?

I don’t know if you watched these videos but Randy (@OffroaderX) discusses some of these things: