WROZ250

MURS rules do seem more relaxed as compared to GMRS/FRS when it comes to data. It seems that APRS could be used, but strictly in a peer to peer mode. Store/forward, which is essentially what digipeating is, would also have to be turned off. Again, digipeating is normally active on all APRS devices. It is one of the key features and what makes it so useful. UserX who is out of range of UserZ, can still get the information via UserY, who is in range of both UserX and UserZ, by relaying their respective data. There is admittedly a lot of 'interpretation' involved here where the rules are concerned. However, fundamentally speaking, for all of the hassle disabling what is IMHO, some of the key features of APRS, combined with connecting APRS modems to a hand held, it seems like a waste of time. By the rules disallowing store-forward on data (APRS or other), they have, IMHO, overlooked the usefulness of location data in these services in, as you mentioned, search and rescue operations. Is it still useful? sure, but not as much as it could be if they allowed store-forward. ?

In a nut shell, part 95 states Digital GPS data (Think DPRS, which is GPS and SMS data using digital modulation as used on DMR systems). APRS is analog data (Audio Frequency Shift Keying). Additionally, GPS data cannot be sent through a repeater, can not be 'digipeated, and (apparently) can only be used on handheld radios with integrated antennas. 'Digipeating' is how APRS extends the range of sent data. Each receiving radio can be configured to repeat data packets not sent to them specifically. Again, this is not allowed on GMRS/MURS. You send it and whoever gets it (if anyone) that's it. Admittedly, this seems like splitting hairs, but that seems to be the rule as written.

Yes, that is 'the book' on doing it right! That said, NOTHING can guarantee 100% protection from lightening other than perhaps throwing the coax out the window during a storm. However... Lightening and damaging static buildup can occur anytime and under any conditions which is why proper suppression and grounding is a must do if you like your equipment. Just having wind blowing over ones antenna, for example, can generate a static charge/build-up. In some cases, large enough to knock you on your ass. Image what such a charge would do to your equipment! The list of possibilities is long when it comes to noise, static discharge, and lightening. The R56 manual was written as a standard for commercial systems. As such, some of the topics will seem expensive, difficult, and/pr impractical to implement for non-commercial operators. Still, one should strive to get as close to what is recommended for their own system. For example, something as simple as bleeding off static buildup in an antenna system alone, typically improves receiver performance. If nothing else, the R56 is an incredible reference that should be read. Just my opinion.

A little late to the topic here, but I think the OP needs to reread Part 95. While GPS 'data' is legal on MURS and GMRS, 'APRS' (as most know it) would not be legal due to the nature of how APRS functions. Yes, it's splitting hairs, but as they say, the Devil is in the details. I'm pretty sure the data transmission rules were written as to prevent the use of APRS for exchanging GPS 'data' over MURS and GMRS. As always, to each their own.

By Default, CH3 is 462.6125 (simplex) and on a GMRS radio, the power limit is 5W. If the DG-20G was unlocked from GMRS to VHF/UHF, the new default CH3 would be blank. Which in theory, would take it out of the channel rotation (never shows up when you hit the up/down buttons.

Your display suggests you are transmitting on low power. However, even on RX your power supply should be indicating some current draw which it appears not to be doing. Low power TX draws slightly more than RX. Also, never troubleshoot power with the system antenna, use a dummy load. But something is definitely wrong in this photo.

Agreed! Unless you are extremely experienced, don't try and make your own jumpers, as @Sshannon stated, buy quality manufactured jumpers of the best cable type you can afford, and absolutely weather proof the connections!!! (Still can't believe there are duplexers with SO239 connectors...)

What kind of repeater, not to mention duplexer, uses PL259/SO239 connectors???

Well, it's been not quite a month now since I received a partial refund* for a brand new BCR-40U I purchased back in February. I received the unit in early March and it was bad out of the box. I contacted Bridgecom who instructed me to 'open a ticket'. In fact, they don't do anything until you go through the process of opening a ticket. Then you wait anywhere from a day to a week for a response. I had my suspicions as to where the problem lay and informed Bridgecom that I could, with their approval, crack the cover and diagnose the problem and, that I am not only qualified to do this, but have state of the art test equipment (if required). However, they basically insisted that I send it in to them (at my cost ~$90 USD) I sent it insured of course, but even if I hadn't, it would have been about $50 to ship it back. It turns out, it was a bad duplexer (as I suspected), and so they sent it back and it worked fine, save for yet another issue (I'll get to that). Less than a day later, it stopped working for no apparent reason. This time I decided to at least look at the programming and found that the repair tech left in a test channel and, after I removed it with the software, the repeater started working again. Now to the next problem... One of the first things I found wrong with this repeater is that if you program in a user with DCS on RX, that is the only user you can have, included the sysop/control user. Tone squelch users, you can have as many as you want up to the limit of 23 users/coded squelch per channel. After reading the manual and all of the sales literature, which makes no mention of this limitation, I Contacted Bridgecom (again), and they basically became forthcoming and stated it was a limitation of one of the chips controlling coded squelch system. It is also important to note, that per the instruction manual, the unit IS CAPABLE of multiple DCS users. Indeed, I think it was me pointing out that fact they agree to refund my money. After that last confession and 2 primary failures, I decided enough is enough. You spend good money for a new repeater you expect better. So I requested and received a refund, well, sort of. The refund appears to have been short the tax I paid for the original purchase. Compound that with the fact that I had to pay to return it twice (once for the repair and once for a refund) at a cost to me of just shy of $200, I am out of pocket about $250 just for 'trying' a (brand new) Bridgecom repeater. I'm really sad to have to write this, but others should be warned. I very much wanted to support a small American vendor/manufacturer, but I've never been so disappointed with any vendor/manufacturer. Between the failures, slow service, basically false advertising (the DCS issue) and, having to pay to return (again twice) a unit that was defective from day one, it was just too much. I'm kicking myself today because what I should have done was purchase a used Motorola repeater for less than what I paid for the 'new' BCR-40U. And I am not talking buying off eBay either, there are plenty of mainstream dealers where you can get a used MTR2000 or even a Quantar for less than the BCR-40U. Bottom, line, I have to call the Bridgecom BCR-40U a 'Don't Buy'. Not just for the defective unit, but also their warranty policies which leaves a customer out of pocket. I had to pay for their problems? WTF?? Indeed, given their service/warranty policies, I don't think I'll ever buy anything from them again. Just my own experience, FWIW!

You know, I did miscalculate! I pulled a "Michael Bolton" (office space) and put the decimal point in the wrong spot! It's .167 dB for a 6ft jumper. a difference of 1.45 dB! That changes the total loss to just 3.08 dB. Therefore the power to the antenna is actually 43.9 dB or, 24.5W which with the antenna equates to (much better) ERP of 97.7 W. Definitely an improvement. Thanks for the catch!!

My interpretation is 50W max measured at the output of the transmitter (e.g. not at the duplexer). That said, and as I've stated in another thread, start with forgetting about watts (for the moment), and recognize that 50W is roughly +47 dB. Start subtracting all of the antenna system losses from that point. Simple (conservative) example (insert or remove your own variables as desired) Transmitter to duplexer jumper (6ft of RG142 @ 8 dB per 100ft) 0.54 dB of loss Duplexer 0.8 to 1.5 dB of insertion loss. Lets use worse case 1.5 dB of loss Duplexer to feed-line jumper (6ft of LMR400 @ 2.7dB per 100ft) 0.16 dB of loss <Corrected! 1/2 inch hardline (50 ft @1.44 dB per 100ft) 0.72 dB of loss Feed-line to antenna jumper(6ft of LMR400 @ 2.7 dB per 100ft) 0.16 dB of loss<Corrected! Total antenna network loss (one way) 3.08 dB total antenna network loss loss <Corrected! Power making it to the antenna = 43.9 dB or, 24.5 Watts (<Corrected! Antenna Gain 6 dB (note not dBi) of "gain" ERP (Effective Radiated Power) of: 49.9 dB or 97.7W.<Corrected! Also remember that the gains and losses go both directions! Thanks To @Sshannonfor catching the error! In most cases, jumpers between transmitter and receiver and duplexer are required but one need not necessarily use RG142 (Teflon) or 6ft of length. Jumpers between the duplexer and feed-line (hard line/Heliax/whatever you call it) are commonly used as to connect "hard line" directly to a duplexer. Same for the antenna to feed-line. You don't strictly have to use them/do it as I have described, but it is good practice. That said, substitute whatever numbers/components you like. In the case of the cables, use the loss specified as close to 465 Mhz as possible. Finally, the point of this was to show that one starts by using the dB (not watts). As good online calculator is: https://www.antennas.ca/calc_db_watts.htm As seen in the above (conservative) example, one can vari the losses by a few tenths of a dB to several dB by the choices one makes. In this example, the duplexer insertion loss could have been assumed to be the ideal 0.8 dB. 7/8" hardline could have been used instead of half inch, and of course the jumpers could be different cable and lengths. All of the above assumes clean, properly installed, connectors, as a bad cable connector can really ruin ones day. Hopefully this gives a better idea of how to think about antenna systems, repeater or base. Lastly, looking at cable specifications, all cable is not created equal. As popular as LMR400 seems to be with people, it's not all that great at UHF for runs over 50ft. Hard Line/Heliax can be expensive, but if one is looking to get as much power to and from the antenna...

You might want to check these guys out: http://www.westmountainradio.com/ Look at their pwrGate products

Right up there with the guys bragging about how their CB was 'tweaked/tuned' and now has 120% modulation. ? I made a small fortune in my early 20s fixing these 'tweaked/tuned' CBs. "This guy told me if I tighten down the screws in those little metal cans I'll get more power". My all time favorite: "if you stick pins in your coax, they'll act like little antennas and improve your signal". Yeah, right, sure it does. (yes, people actually did stuff like that) LMAO ROTF!!!

Unfortunately, short of a 2-way radio service center, no. I have no idea what that would cost these days. Alternatively, if you know any hams or perhaps even a local club, there is almost always one or two people who know how to do it and, have the proper equipment. LOL! Super Tune to me says more bad than good about the person saying that. There is tuned and there is untuned. ? That said, general issues with the NanoVNA aside, if this duplexer is not giving you the expected performance, and you've already played with it, you really have nothing to lose and everything to learn by trying again. There are ways to configure the nano settings to allow you to better see the combined tuning (as apposed to just one cavity). The view takes more time in these modes, so patience is required, but it should help the resolution a lot. For example, the bandwidth, sweep speed, and #sweep points can all be reduced or increased as you get closer to 'fine tuning', to allow you to see a more defined reject notch. I believe W2AEW has at least a couple of Youtube videos on duplexer tuning with the Nano, and this is a guy with a lot of experience. I'd suggest going to his list and search for Nano and duplexer to find them. Nothing is a better learning tool than doing and trying. Worse case scenario, you pay a service shop to tune it. Sorry I can't be of much more assistance.

Pretty sure the loss you described is not normal. I've never encounter that to my recollection, at least not with a properly tuned and working duplexer. It would cause me to investigate further. It could be a sign that the duplexer (as a complete unit) is not truly tuned correctly. It is possible that it could also be the difference between your RF load and the duplexer (impedance-wise), but even in that scenario, 8 watts across a jumper is excessive IMHO. Sorry, it's really difficult to diagnose a problem through messaging! The reason I suspect the duplexer is that without being fine tuned as a unit, as I stated previously, simply tuning the individual cavities and connecting them together rarely (if ever) works and, any mismatches within the chain of cavities will be seen at the ports. This again, might explain what you are experiencing. ?

The thing about vswr is that 50 ohms isn't quite/exactly 50 ohms between devices. There is always minor differences (Very Minor) between say the analyzer/VNA and the repeater itself. So not having a perfect vswr is normal. Having a vswr that jumps around, not so normal. Most duplexer specifications will include a nominal vswr to expect/consider normal. I agree with you about the using VNA with the individual cavities. However, when assembled as a whole, there is typically some interaction between the cavities and the cables and so tuning a duplexer is more than simply tuning the individual cavities by themselves. Indeed, bad inter-cavity cables can really cause some issues. Bottom line, no matter how well the individual cavities are tuned (independent of the duplexer as a whole), most of the time when connected them together to for the duplexer, some additional tuning is required. Additionally, if you repair or replace the inter-cavity cables, know that to some extent, their length is critical and so will also impact the overall tuning. If you use a different type of cable (RG-8 verses RG-214) the length may be different depending on the velocity factor. There are many excellent videos on Youtube for explaining and performing duplexer tuning. If you want the best possible performance, a duplexer has to be tuned properly. The mere fact that it is a commercial grade base/repeater duplexer is irrelevant. I had people send me these units to tune and some were so poorly tuned and/or repaired, the CCD types were actually better by comparison. The goal is to squeak out every possible dB of rejection and pass to get optimum performance. That again, can only be done through the proper procedure with the correct equipment. All that said, I have seen people tune a duplexer using a signal generator, a step attenuator, and a good receiver with either an S meter or SSI output. It's a 'down and dirty' way to do it, but done properly and carefully, one 'can' get some pretty good results. Not nearly as good as the proper procedure, but not horrible either.

Ironically, to construct a really good repeater system, the cost of the antenna system (situation dependent) can many times be more expensive than the repeater itself. As far as the 102" whip. It could actually be used in theory, but you'd need a matching network which, at UHF, would be a project in itself. Basically, it would be some sort of 'long wire' antenna, the pattern of which in this application, would be difficult to know if it would be useful. Probably better off/easier going another route.

I would first test the duplexer with the output terminated in a known good 50 ohm load. I would also check to ensure each and every connection is tight. One thing about duplexers is that even a slightly tight/loose connector can give you fits. That particular duplexer, as I recall, has a piston (plunger) type notch capacitor. So like the main tuning rod, you need to ensure that it too is securely tightened (once tuned). If it''s an older duplexer with some 'mileage' on it, the cables and/or their connectors could also be suspect. I seem to recall the 696 used RG-214 or similar jumpers with soldered on N-type connectors. Don't be afraid to wiggle these to test them, like the connectors being tight enough, a bad cable or one of it's connectors can be a headache. I don't know what VNA you are using, but I will say that if it's one of the NanoVNA types, as good as they are, they simply do not have enough dynamic range to accurately tune a duplexer. You can get really close to be sure, but it gets really difficult to accurately tune the notch side and that, can make a difference of several dB of loss elimination. IMHO, the notch is almost more important than the pass side. While certainly not the only way, the best method to check/tune a duplexer is with a professional VNA (Tektronics, etc...) or, with a quality/decent spectrum analyzer with at least 120 dB of dynamic range (preferably more). I use a directional couple with the Spectrum analyzer and tracking generator to tune and to check the return loss. The latter is to a large extent, is like vswr, but is far more obvious about where you pass or notch is and how good you have it. If you get good results testing into a known load, then and only then check the system with the antenna. Never check a duplexer with the antenna system connected as it can skew the results. Sorry for the long message, but I hope it helps you out! BTW, those CCDs (Cheap Chinese Duplexers)... it's not (necessarily) because they're Chinese... Those things are crap no matter who makes them!

I have the SDRplay (RSPdx) and love it! And yes, if that is ones desire, it is fairly simply to use it as a pandapter in many HF rigs.

Interesting... Wondering what would constitute a 'fixed station' beyond, for example, two base stations in addition to talking to mobiles and portables, but were also used to talk between themselves. would that not constitute 'fixed station operation? Kinda mute in the bigger picture, as who would really know (or care) unless said operation was causing interference to another GMRS operation, such as a distant repeater. Still, outside the two base stations talking to each other scenario, what would be an example of fixed station operation (data link?). While legal, one would think using a GMRS frequency as a point to point link between repeaters 'might be annoying' to other users. It is a valid point (no pun intended) in any event. ?

Been a few years since I attended Dayton. Last time I was there was the last time it was at the Hara. However, unless the 'flea market' has drastically changed, if you can't find what you're looking for there and, at a great price, you can't find it. We use to scour the flea-market area late Sunday, looking for even better deals (funny how much prices drop when somebody wants to go home with more cash and less radios) and sometimes, you'd get a surprise with what people just didn't want to take home. LOL! One of the things I miss about living in the Midwest, Dayton was only a few hours drive. We use to stay there in groups, usually reserving a block of hotel rooms well in advance (like 6-12 months). Great memories!!! Unfortunately, AZ to Dayton is a bit impractical these days. Combine that with the Pandemic impact, these days I am so jonesing for a good hamfest... ?

That 50W limitation is not a blanket statement even on the channels where it is the maximum. If one is playing "strictly by the rules", a fixed base radio (i.e. not a repeater and not a mobile) is limited to just 15W again, even on a channel with a 50W maximum. (47 CFR § 95.1767 - GMRS transmitting power limits.)

Agreed, the waterfall is hardly a this radio or that one factor. It's nice but there are other alternatives. A big factor for me would be that the 7100 is older tech and is perhaps, closer to end of life as a product. As for being better for portable, I'm not sure where the OP was going with that comment. Both radios are 100W on HF (variable) and the current draw would be similar. If anything the separate head and it's cable would, IMHO, be cumbersome for portable ops. The 991 isn't that big of a radio. Just an opinion...

TK780H is VHF

And that is expected to be the case, probably about the same time the GMRS license drops to $35. $70 for 10 years is just $7.00 a year... not all that terrible anyway (IMHO).