marcspaz

I think "it depends" is the best answer. I've owned and used well over 100 radios in my lifetime, varying in price (new) from $5 to $7,000. In my adventures I learned there is a huge difference between cheap and inexpensive.

Good deal. Have you gotten to the point where you are considering a particular repeater?

So much truth. While I have a CB it is performs very well, I only hook it up if I need to use it with the occasional person I'm wheeling with who doesn't have FRS or GMRS.

Based on the pictures, the o-ring wouldn't touch the mount to seal it, even if the radials aren't installed.

I would like to caveat for those without the experience, I found out in a somewhat painful way that SureCom SWR/Watt Meter and the Erik/ZeenKo TinySA and NanoVNA fall into the "Close Enough" category. Meaning, you are not going to be doing precision measurements. It's not that the TinySA and NanoVNA are inaccurate, per se, but rather they do not have a fine enough resolution for the type of work you would do with tuning a transmitter or a duplexer. However, you will be able to use all 3 devices to see if your SWR is broadly in a safe range, approximately what you power is, and other types of GO/NO-GO results.

Your response seems unusually harsh, especially considering you have asked such a novice question. Maybe I'm misreading it. That said, there is an overwhelming amount of new people that come here convinced they need a repeater, when the know nothing about radio and have only had a license for a few weeks to a few months. Given how long some of us have been around and seeing the trend of unnecessary repeater build ideas that never come to light, it's not an unreasonable question to ask why someone new thinks they "need" a repeater. Especially if there are some already in the area or possibly another solution. Also, not everyone can afford putting a repeater up, not realizing putting a quality and reliable repeater on the air cost anywhere between $15,000-$20,000 when you include the mast and antenna system. On the high-end I have a friend who spent over $1.8m to get a 300' tower built to install his repeater system. Even on the low side, if you have access to free tower space, you're going to spend $5,000-$7,000. If there is another option available and someone can help me find a better or alternative solution that doesn't cost me a fortune, I would want the feedback. If someone just wants to understand "why", I wouldn't be mad that they asked.

Much better response. After reading the question again, I'm thinking you are right. To use literal examples, a repeater can be configured to operate if it receives a 141.3 tone or a 127.3 tone (just random tones I picked for the examples).

Yes. Many repeaters can have 2 or more tones. Many can have a receive tone that is CTCSS and transmit a DCS tone (a type of split tone configuration). Still more, some repeaters can also use a paging system where they only open the receiver if they hear two tones simultaneously, and transmit either the same two tones or two entirely different tones.

With only 8 pairs, it can get crowded in some areas. It sounds like you are on the right track with the steps you have taken. Nothing is fool proof, but if you are really concerned, along with the monitoring you are doing, I would recommend publishing your repeater info. This way, if you end up causing interference with a previously existing repeater, the legacy repeater owner will have some way of contacting you. For what its worth, there are several repeaters around me on the same frequencies and overlapping coverage. The repeater owners have talked amongst themselves and agreed to leave every machine up, have their regular users operate with a custom tone, and all run 141.3 for travelers and emergencies. It has been working out very well for several years, with very limited interference. Just about everyone has been pretty happy with the coverage and availability.

I appreciate the feedback... @WRYZ926 that is good to hear on the good performance over the past 6 months. I have my own duplexer as well. I'll end up getting the one without a duplexer.

I am looking for a commercial grade, inexpensive and portable (4U or less) repeater for emergencies. The BridgeComm BCR-40U looks like it will fit the bill and they advertise it as being usable on GMRS, but I can't find anything with regard to part 95 acceptance in the FCC portal. Does anyone have a link or FCCID I may be able to use to look it up? Also, I'm looking for feedback on this repeater and it's performance... for anyone who has or had one, what do you think about it? Stability good? Any overheating or receive sensitivity issues?

It's better to let those who know you defend/brag for you. That way you don't look egotistical. I should really follow his example... but sometimes I can't control myself. LoL

I played around with this radio a bit today. I can confirm that the 2-pin speaker-mics from Baofeng, Pofung or BTech (like the QHM22) and the 2-pin speaker-mics that fits Kenwood radios (like the TH-D74A) do in fact work with the TD-H3. Oddly enough, of the BTech QHM22 had the best audio.

This is a great example of what you are talking about. Randy nailed it with this.

From the perspective of an amateur radio operator... operator... I love Randy's videos. I even have a paid subscription with him to help contribute in some small way to the equipment testing and content creation. Truth is, his content is funny as hell and very helpful to many, including me. I love that he doesn't take crap from anyone and his socio-political humor is great. I have had the pleasure of having some private chat messages / emails between him and I also... and learned pretty quickly that he is a great guy. People seem to lose track of the point that there is an entertainment persona and then how he is in his day-to-day life. Like my wife reminds me when I start griping about inaccuracies in movies and TV shows... 'It's for entertainment. Just let it go.' LOL

I noticed that there is a 'cigarette lighter' style 12v power connector with it, too. I assume that lends to charging on the go, too. I'll have to checkout the channel of a certain YouTube hobo and see if some recent videos shed any light.

Today, I lost a friend; NOVA GMRS lost a beloved member. Roland Jackson (WRPJ758) died today. For those in the DC Metro area, he had a positive impact on the community. Roland was a staple in the GMRS realm, willing to help anyone, chat with everyone. You will be missed my friend. Pictures care of @kidphc

@WRKC935 understood and all good information. I have a UHF duplexer, so no issues on that end. I am trying to solve for an amateur VHF EmComm issue if we need to use a frequency other than what any duplexer may be tuned for, without having to re-tune the duplexer on the spot in the field. In the past, horizontal separation has worked extremely well for us with my original repeaters, as the up-link and down-link are to separate radios a significant distance apart and RF linked. I was hoping to accomplish the same results, but with a single repeater... though, it's not promising. There is a good possibility that I will tune a duplexer for the single repeater solution and tote my original split system in case it's needed. The main reason I shared what I did is because several people over the years have askes about if a duplexer is needed for a repeater or not. This was a real-world result rather than a theoretical bench test. The bench test is great, but for me, actually hearing and experiencing the results translates to something more meaningful and easier to digest. Plus, it helps me explain in some odd way that no duplexer is needed in limited circumstances... but it's far from perfect. Something I did find interesting is, while there is noticeable desense in the test I did, with a 35 foot portable mast, I actually ran out of LOS before the desense led to loss of comms.

43' vertical separation.... We're going to need a bigger tower. LOL There is some serious benefit to the commercial duplexers, for sure. I have seen some better units with 90dB notches.

Sorry, this is a little long. Hopefully not TL;DR long. This is somewhat Emergency Communications related, but will hopefully answer some questions a lot of new people have about needing a duplexer for a repeater. I have to say that you need a duplexer if you want to use one antenna. There is no way around that. However, you can run a repeater with two antennas if you have the physical space to work with. I have been playing with repeaters for some time. I have never run a duplexer with any of my repeaters, but rather using two antennas physically separated horizontally. This is because most of my repeaters are intended to be used in the field during an EmComm event. So, rather than re-tuning a duplexer while trying to resolve frequency coordination issues in the field, we can simply pick our new frequency pair and carry on. I never really had any desense issues, because I have historically been using two cross-band repeaters, occasionally with as much as 1,000 feet of physical separation and simply RF-linked the two systems. The space between the two systems resolved any desense issues through natural atmospheric attenuation. This weekend, I tried doing some testing to see how vertical separation would work, with both antennas on the same mast. Based on advice from several reliable techs and engineers in the commercial RF world, I figured I would give it a shot. Unfortunately, my results were not as good as what my research implied it would be. The idea behind stacking the transmit and receive antennas is that there are nulls above and below the axis of the antennas. The more separation, the wider the null in the field gets and the more attenuation you get. My problem is, with a portable mast, I can’t separate them enough. I tried clocking the antennas on the mast and had no change in performance worth mentioning, regardless of where they were. First, only using 5w on 145 Mhz, I stack the receive antenna on the mid-section of the mast and the transmit antenna on the top of the mast. Both antennas have ground plans. The initial separation was 40 inches. The transmitter was splashing the receiver with -4dBm / 0.14 volts. I moved them to 80 inches apart and it dropped to -57dBm… still not great at an additional 17 dB of attenuation. Finally, I moved the antennas to 360 inches, a full 30 feet apart. The splash only dropped to -74dBm, about an additional 23dB compared to 40 inches. As a quick note, I was using LMR400 cable for both antennas. Swapping the antenna positions made it so the repeater was completely unusable. The next test was using horizontal separation but wired instead of RF linking. I put the two masts up at 35 feet with the antennas at the top, and same elevation. The masts were only 130 feet apart from each other. I placed the repeater in between the two masts for general testing. Testing in this configuration showed that at 20w the transmitter was splashing the receiver at -120dBm… a shade over 38dB of attenuation compared to stacking the antennas at 40 inches of separation and almost 47dB of atmospheric attenuation in total. At 5w, it was attenuated to the degree that splash was no longer measurable on my SA at the offset frequency. This is pretty good for what it is, as my repeater’s receive sensitivity is 0.2uv / -121dBm. This means that at 20w the transmitter is preventing only the very weakest of signals that the repeater could possibly hear from actually being heard. The cable I am using has a loss of 1.5dB per/100’ on 150 MHz. So, I could increase the physical separation to 340 feet (two 200 foot cables on each feed) and still get 50% of my power to the transmit antenna. Or, I could set the repeater off-center, closer to the receive antenna to minimize line loss on the receive side, turn the power up to 50W on the transmit side and still have plenty of natural atmospheric attenuation for good performance. I haven’t performed any testing on the UHF spectrum yet. However, you need less space for UHF than VHF. I would suspect that you would see at least another 10dB of attenuation at the distance I tested (130’) or the antennas could be placed as little as 40 feet apart with similar performance. I will be testing again on 440 MHz, possibly on Thursday. So, I should be able to confirm. Obviously, having the transmitter and receiver tied together with cables will not provide the low loss and optimal atmospheric attenuation that can be obtained with split-band RF linked systems, but it reduces the amount of hardware you need for radios, power sources and physical security. As long as you have the 200 feet to separate your two antennas, you should be fine.

I used that exact combo for awhile and it worked pretty well. I wouldn't waste effort or money adding a ground plane kit. There is plenty of reflective surface for the antenna to work. I stopped using it because, like @kidphc, I had an SWR that was a shade over 2:1 on the repeater frequencies. That is just how the antenna is tuned.

Is it bad if I turned the volume down on my phone before I clicked on the link?

14 hours of continuous operation in VHF & UHF with no issues, but zip going on in the HF bands.

Depends how important a GMRS compliment radio is to you.

I've never seen a forecast this bad. At least not that I remember. Any of our seasoned folks seen storms this bad in the last 40 years?