marcspaz

For those new to radio, and aren't a complete radio dork.... yet.... 12dB SINAD is a standard measure to describe receiver sensitivity. SINAD stands for 'Signal to Noise and Distortion'. This type of measurement is particularly useful for testing analog FM receivers. It represents the point where the desired signal is 12dB stronger than the combined noise and distortion. A lower input voltage at 12dB SINAD indicates a more sensitive receiver. Receiver sensitivity is the ability of a receiver to detect weak signals. A lower input voltage (measured in microvolts or dBm) at 12dB SINAD means the receiver can detect weaker signals and still produce a usable audio output. A 12dB SINAD measurement of 0.25µV (about -118dBm, -119dBm) is pretty good. Most expensive radios are about 0.200µV (about -121dBm). I looked at that SGQ-450D duplexer specs a few minutes ago. If someone is interested in buying one, while it's only rated for 50w, it actually looks pretty good on paper. 1dB insertion loss is great and both the suppression and isolation are on par with other mobile duplexers that are 3 times the price. Again, zero personal experience with this particular device, but it looks good on paper and @LeoG hasn't thrown it in the trash yet... so those are both good signs. LOL

Due to there being a 5MHz spread between the uplink and downlink, you can make a custom duplexer that would be low loss and provide great separation, but you would have to have a pretty good understanding of electronics and how LC networks work. I am unaware of any commercially available, but if there is one out there and configured to tolerate any reasonable power, it would likely be well over $3,000. I wouldn't be shocked if it was more like $5,000. Actually, the repeaters available from companies like Midland are as expensive as they are, and have such low power, due to having a broad frequency duplexer that covers all channels. They tried to make them as efficient as possible without pricing themselves out of the market.

I may have mentioned this earlier in the thread... but I think the FCC is 40 years too late in approving FM on CB. I'm glad a manufacturer stepped up and got the change made, but it's just too late.

Have to say, I miss the hay-days. Back in the `70s and `80s (a little of the early `90s, too), I had an absolute blast on the CB. I had a base station and also a mobile in every car. My base setup had an ERP of 122kw. When I would fire it up full power, none of my neighbors could watch TV. One of the people closest to me said he was pretty sure my radio caused his refrigerator to hum. LOL Compared to back then, it sure feels like nobody is using it.

This is correct. Anyone can send a message through the Hams. We do it al the time. It's our #1 task with ARES.

For GMRS... 100% agree.

When my old club put a repeater up, it cost over $7M. I doubt we would pull that kind of money together on crowd-fund... but it's fun to joke about. I wouldn't put a mobile duplexer in orbit. That would be a disaster waiting to happen.

I talked 2,039 miles om my HT, from DC to Sonora, Mexico. It was through a repeater on a satellite about 250 miles in the air, but hey....still counts. There are no restrictions on putting a GMRS satellite in orbit. We should start a crowd-funded account to make that happen.

Im not sure you can determine someone doesn't hold a license using this method. I only have two licenses under the FRN that my Amateur and GMRS licenses are under, but I have multiple FRNs. And unless you know what names are associated with my other FRNs, you're not finding them.

I think the stuff that he gets right is either because he got lucky and said the right thing by mistake, or he researched the hell out of it and somewhat properly regurgitate what he read, but doesn't actually "know" what he is talking about. I think this, because right after he says something correct, he will follow-up with an explanation of why he right, but that explanation defies physics. Imagine if I said that during certain conditions, if we shoot a GMRS single dang near straight up in the air, it comes back to earth and covers hundreds of miles in every direction. But then, instead of saying that it happens because signals can bounce off of planes, meteor showers, the moon or (more often than not) random weather anomalies... I say it's because the radio signal is so heavy, it's like launching a watermelon out of a giant slingshot. Its kind of like that.

What I don't get from SoCal is, he either says or has strongly implied that pretty much none of us know what we are talking about, always wrong, and a bunch of NotARubicon nut huggers (sorry, Randy. You know I love you).... and, he seems like he's always mad at us. So why the heck is he wasting his time and talent on this forum? I've asked him... but no response. Maybe it's like watching a car crash. Its so horrific that you can't look away. Anyway Guest PG3, just ignore the stupid stuff he says and try to pull something useful out of it. Honestly, recording the experience if it continues to happen and then filing a police report with local PD isn't a terrible idea. You just need some proof it's happening and you may get some traction.

You definitely got lied to. Every channel is free to use. No one owns a channel or has a channel allocated to them. Law enforcement almost never uses these channels for official business and when they do, you still have as much right to use the frequency as they do. Most of the time, when FRS/GMRS is used by the government, it's not police. Its typically a civilian liaison acting as a go-between for U/SAR volunteers or volunteers working in support of some type of remote response to things like mass casualty incidents. I'm pretty sure you would know if there was a mass casualty incident close enough that you can hear another user directly.

I agree for sure. Anything under 20m is very hard to get communications out of while mobile. 80m and 100% equal to QRP, for sure. 100w in for less than 2w out. If you are actually moving, that makes it even harder. I have seen some guys spend $2,500 or more for some of these high-power screwdriver antennas, but it's pointless unless they have a mobile 1,000w amp. Even then, the 1,000w to the antenna on 80m would be like 150w-180w to a proper vertical antenna (not even a dipole). That antenna would be hot enough to cook on. LOL

@Lscott I tested my screwdriver with a field strength meter and compared it to my dipole and my dedicated whips. On 80m, I only had a 1.8% efficiency rate. On 40m, it was about 30%, and on 20m it was about 50%. I switched over to Diamond mono band 86.6" whips and retested. The dedicated whip was still less that 2% efficiency rate on 80m. However, on 40m, it was 50%+ and 20m was almost 90%.

I guess not. Jack is the guy who submitted the Petition for Rule Making. Some of your posts lead me to ask the question.