marcspaz

Horrible idea. The minimum safe distance for a 50% duty cycle at 20w @ 467MHz is 3.4 feet. Even 10w is 2.5 feet. You need to stick to an HT or get the antenna outside.

I have a analog Swan power meter that I use for measuring peak AM/SSB power, upto 3,000w. It has a capacitive circuit that holds the peak and slowly drains off. That is the only meter I use for tuning my radios or amps. I use the Bird for legit engineering, bench testing and repairs. I only use my Diamond and Surecom meters for monitoring low power FM power and SWR for day-to-day use. I'll make you laugh... I almost never use the Surecom unless I am looking for a "Wow!" factor for people who are new or know almost nothing about radio. People love stuff that lights up! LOL

Wow... That 4391 is $2,300 and the 4421 is $4,600. I get upset when I spend $500-$600. LOL Those are pretty nice meters and I am not shocked I haven't seen them.

To the best of my (very limited) knowledge, Bird does not make any watt meters with a digital display.

As I mentioned, I would replace the one you have. Not align it. I would never trust it because of how far off it is. To align the unit, there are a couple of different methods you can use. The first method, which is the fastest, but least accurate way, is to compare it to a known good/accurate digital meter and simply use the menu adjustments. The other is to use a generator and dummy load to calculate the value and dial it in. To use the second method, you are going to need a stable signal generator (+/- 2.5 ppm) that will operate at 0.5w, a VAO meter, and a dummy load and appropriate barrel connectors (don't use patch cables). You measure the resistive load to confirm it is indeed 50 ohms. If its not, make a note of whatever it is. Turn on the signal generator while connected to the VAO meter and dummy load, set the generator to 0.5w and measure the current and the voltage. Use E/I*R and P/E*I to confirm all of the measured values are correct and to calculate your wattage. Then, replace your meter with the SW-102 and turn the generator back on. Go into the SW-102 menu and adjust the frequency to read correctly. I can't get SureCom to tell me what wattage we are supposed to calibrate to, so I just used 50w and that seemed to be a good number. From there, increase your wattage to 50w and adjust the voltage controls (forward and reverse/reflected power) as needed. Be sure you have the USB cable connected as a power source while adjusting.

I would try exchanging it first. You definitely have a bad unit, but I think it's just bad luck. Also, the device is capable of being calibrated by the user. Once I calibrated mine, it's as accurate as my Bird 43, which is a benchmark product at more than 8x the cost of the SureCom SW102.

Okay… here are the numbers. I will list what the Midland test numbers are and what I got for results. My results – Max Output: 47.9w @ 462.550 MHz 12 dB SINAD Sensitivity: -122 dBm / 0.177mv Midland results – Max Output: 48.3w @ 462.550 MHz 12 dB SINAD Sensitivity: -124 dBm / 0.141mv Overall, I am very happy. My numbers are close enough to their numbers that I am questioning the accuracy of my TEK or coupler more than their results… probably needs a calibration since it’s been almost a decade.

Good points... Chasing great SWR is not needed in many cases. There is an aphorism I like... "The best is the enemy of the good." or the modern version "Perfect is the enemy of good." It is widely accepted that an SWR of 3:1 is the maximum safe SWR. Many radio's will alert or shutdown transmit at anything above 3:1; and still others will detune (pull back power) if the SWR is otherwise unsafe. At 3:1, if you start with 50w into the antenna, you will have 37.5w ERP (on a zero gain antenna). Not fantastic, but I wouldn't be tossing stuff in the trash either. A 2:1 will be about 44w ERP, which is pretty good. Depending on how performance is elsewhere, I may not even attempt to improve a 2:1 in a low power system. Especially when many antenna manufactures don't even guarantee better than 2:1 on their budget-friendly products.

Along with what is mentioned above, you should be tuning for 465.1375 MHz, the center of all of the channels. That will allow for maximum performance on all channels/frequencies.

I am really tired and hope I am typing this right. LOL There are two types of ohms readings we are dealing with when we talk about these different tests. There is a inductive load which uses magnetic fields to move energy. Then there is a non-inductive load, called a resistive load (aka dummy load). An antenna is an inductive load and the value of the load changes as the frequency changes and as the length and even diameter of the antenna changes. Meaning the Ohms value changes as you change just about anything. A resistive load is a fix value resistor (device that is the opposition to current flow). It's value is extremely stable across great expanses of radio spectrum, and are typically only going to become an invalid test device (not being 49 to 51 ohms) if the material gets too hot or the physical makeup of the resistor is not designed to perform in the specific frequency range you want to test. Even a near perfect antenna install is normally not a good test platform for true/scientific results due to so many variables that can impact the magnetic field as the energy travels from your radio, to and through your antenna. Based on that, typically the antenna systems are not used for testing. On occasion, however, for non-scientific purposes (general discussion) we may conduct a test involving an antenna if the antenna is the subject of the test or the "known to be inaccurate" results are "close enough" to illustrate a point. eh... not exactly, no. You are correct in that the further you get away from the frequency the antenna system is tuned for, the more things change. However, that "thing" is that the antenna system becomes unbalanced and you can start to get artificially low or high power readings. The value you see is the actual wattage. Watts is a mathematically calculated value, which is: Power = Voltage * Current. As we stated earlier, if the load (reactive or resistive) goes up (ohms increases) the current flow slows down. Assuming a perfect world, the voltage in the radio has not changed. There for the power goes down. If the load (reactive or resistive) goes down (ohms decreases) the current flow goes up. Again, the voltage in the radio is assumed to have not changed. Therefore the power goes up. Correct. But that is only part of the process. The load needs to be balanced (1:1 VSWR), but the voltage also needs to be correct, at 13.8vdc measured at the radio. Not at the power supply.

SWR shows balance. If you have a 25 ohm load or a 100 ohm load, it's still a 2:1 SWR. However, if you have a 100 ohm load, the current is lower, therefore the wattage is lower. If you have a 25 ohm load, the current increases, therefore the wattage increases.

My farthest 2m contact was with someone else's gear. I was on Flagpole Knob (about 4,000' ASL) with the Woodbridge Wireless radio club for Field Day about 20 years ago. Stacked beam array, 1500w on 144.2 MHz USB. Talked from Dayton, VA to just over 1,000 miles to an operator just south of Dallas TX. That was pretty awesome.

I wouldn't expect any miracles on 2m. LOS is LOS. Using power to overcome shadowing is a high-loss game. I'll be impressed if you pick-up an extra 0.5-1 miles. My own personal experience, watt for watt and all else equal, I don't get an extra block in my neighborhood, moving from GMRS or Amateur 440 to 2m.

That is what the monitor button is for; to confirm the channel is not or is in use and to see if it may be someone you want to talk to, who isn't using the same user squelch you are.

Hey folks, I am leaving for vacation in a couple of hours and don't have time for a proper test... but I wanted to let you all know that I got the radio back from Midland and I can't be happier. With a quick bench test using low pressure alligator clip test wires for the power supply, I am now getting 48w of output power on both the 462MHz and 467MHz frequencies! I'm sure with a proper power cable, it will be perfect. Once I get home and have a chance to do some proper testing for output power and 12dB SINAD receiver sensitivity test, I'll share the results.

@mbrun I love that feature. Some of my radios also light different colors, depending on if the signal is analog or digital

All great info to add! Thank you both!

Found a 20w... https://www.retevis.com/high-gain-antenna-rhd-701-sma-female-dual-band#C9045AX1

Yes, the mount an associated cable will support a 20w system. The question is, will the antenna you buy support a 20w system. That mount comes in options for antenna compatibility. BNC, SMA and reverse SMA. I would find an antenna you like and buy the corresponding mount. All of the types it supports are handheld antennas. So I wouldn't expect much in the power department. Max is typically 10w. Example: https://www.buytwowayradios.com/nagoya-na-771g.html

I have used glass mounts before. Its a compromise, but they work(ish). It will be better than an HT. Just be sure you don't trash the window seal when you roll it up. I would be more prone to use this... Uses something like superglue to mount to the glass. It will look a lot cleaner and when you decide to remove it, you will never know it was on the glass. https://www.amazon.com/TRAM-1192-Pre-Tuned-150-154-Dual-Band/dp/B07B9V77BH/ref=asc_df_B07B9V77BH/?tag=hyprod-20&linkCode=df0&hvadid=270610367741&hvpos=&hvnetw=g&hvrand=14561024409338638345&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9008161&hvtargid=pla-574076094856&psc=1

So, no mag mount, no lip mount, and you don't want to drill holes. Have to be honest, i have no idea what else you could possibly do except use your handheld. I mean, you are asking how to mount an antenna without mounting an antenna... so holding it is all that is left. What kind of vehicle is it? I mean, I put a lip mount on a $100k Challenger Hellcat that was even painted black and had zero issue with the paint. That really is the best method if you want it to work and not have damage.

Hey folks. I have had a small group of people ask me about tones and GMRS/FRS basics in the past week. I figured I would take one of the conversations here and share it for people new to the service. Hopefully it will help you understand Private Lines, Privacy Tones, sub-channels, tones and squelching methods, in general. I am only covering the two most popular in GMRS and FRS, but there are many others available as you move into different radio services and technology. Before we get into what all that stuff is, lets talk about why it exists. Per NOAA and the US Census Bureau, the lower 48 states is approximately 3.1 million square miles. Also, 83% of Americans live on 10% of the total available square miles and 40% of all US citizens live on the east and west coast in counties touching oceans. Following this logic, about 500,000+ licensed and unlicensed operators (estimated by me) are sharing FRS and GMRS radio space, in roughly 310,000 square miles. So, how does 500,000 people in close proximity, sharing 22 channels, all use their radios at the same time without interfering with each other? Motorola brings you PL tones! Lets get this out of the way... regardless of what the manufacturers may tell you or how they label their products, there is no privacy. Period. Private Lines (PL), Privacy Tones, Sub-channels and any other name for the same service, does not stop people from hearing you, it stops you from hearing them. I know... seems like a day in Opposite World, but that's how it works. I suppose the first thing to do is explain what the PL tones really are, what the more common types are and what each of them do. A traditional squelch is a signal level squelch. Meaning, no audio will come out of the speaker until a strong enough signal is received. Then there are also user squelch types. With analog radios, the most common type of user squelch uses encoding called Continuous Tone-Coded Squelch System or CTCSS. This feature is defined as being used to reduce the annoyance of listening to other users on a shared two-way radio channel. So, as mentioned above, its not that you as a person speaking have any type of privacy, but rather you don't have to listen to everyone on the same frequency. Hopefully the third time is a charm. Many GMRS and FRS radios only have simple CTCSS functions called Tone Squelch, often displayed as TSQL on the screen when enabled. This means two things. One is, regardless of what you do with your squelch knob or set your RF squelch to, no audio will come out of the speaker unless the tone you selected is embedded in the signal you are receiving. The other thing it does is, when you transmit, what ever tone frequency you have programed gets transmitted with/in your signal to unlock or open the squelch of other radios configured the same way. There is another method of CTCSS called "split tone". This means that you can use one tone when you transmit and another for your receive. This comes in handy when repeater owners are trying to limit who can access the repeater, as higher cost radios typically have split tone capability, compared to poorly built and inexpensive radios that would be problematic on a repeater do not. Also, this makes it a bit more difficult to "discover" the input tone by using scanning tools. Another function of split tone CTCSS is that you can also set your radio to transmit a tone to unlock a repeater or other radio, but leave your receive tone set to null (nothing). When this mode is enabled, there is typically a display on the radio that either reads TN or TONE. That means you can bring up a repeater or unlock a radio squelch, but also hear everyone else regardless of what tones they are running, if any at all. This is actually a great feature for GMRS radios since Repeater Channels share FRS frequencies and GMRS simplex frequencies. So you can tell if the frequency is in use as well as being able to talk to others who many not be using the repeater. CTCSS is an analog squelching system. There is also a digital squelching system called Digital-Code Squelch or DCS. It has similar use cases as CTCSS, but it is sending digitally embedded numeric codes instead of a sub-audible tone. I apologize in advance, but this next portion may get a little confusing. If you have questions, just ask and myself or one of the other knowledgeable members will be able to help. All of the numbers below are simply random samples I selected for example. Last I checked, there are 38 standard tones and an additional 13 expanded tones (not available on every radio) for a total possible 51 tones and 83 DCS codes. Along with the use examples above, you can get creative with DCS, because we are dealing with binary numbers instead of a tone. You can have the numbers used in a bunch of different combinations. For example, the number 411 in binary is 00110100 00110001 00110001. The reverse of this would be 11001011 11001011 11001110. So we are swapping the meaning of a 1 and a 0. So the combinations could be as follows: Normal-Normal = Transmit sends 411 and your radio squelch only opens when it receives 411 in the standard format 00110100 00110001 00110001. Reverse-Reverse = Transmit sends 411 reversed (or bit swapped) and your radio squelch only opens when it receives 411 reversed, meaning 11001011 11001011 11001110. Normal-Reverse = Transmit sends 411 standard binary format and your radio squelch only opens when it receives 411 in a reversed binary format. Reverse-Normal = Transmit sends 411 in a reversed binary format and your radio squelch only opens when it receives 411 in a standard format. Unfortunately, I am unaware of any radio's that have a DCS option to leave your user squelch open while transmitting a DCS code. If DCS is enabled, you cannot hear anyone else unless they are using the same DCS number and binary combination. CTCSS tones can also be "reversed". CTCSS tones, since its analog, we have a phase reversal, often called "reverse burst" when it is only reversed at the end of the transmission. (Something to Google in your spare time.) On some high-end radios, squelching can get really exotic. You may be able to create your own custom tone instead of using one of the standard tones. You may also be able to combine CTCSS tones and DCS codes. For example: User-CTCSS = Transmit 2600Hz tone, squelch opens with 2600Hz tone. (random number example) T-DCS = Transmit 141.3 tone, squelch opens with 411 code. DCS-T = Transmit 411 code, squelch opens with 141.3 tone. T-rDCS = Transmit 141.3 tone, squelch opens with 411 bit swapped code. rDCS-T = Transmit 411 bit swapped code, squelch opens with 141.3 tone. Now, here is the kind of disappointing part. Some manufactures try to make their equipment sound like something its not. They will use things like there own custom number code to identify a traditional CTCSS code. For example, Midland uses code number 22 (also known as a sub-channel) to indicate the tone 141.3. This makes coordination on tone selection a bit cumbersome between some brands. It also means that if your radio doesn't display the actual CTCSS tone or DCS code, you need to keep your owner's manual handy for reference. So... I don't know if that explanation made things better or worse. LOL Anyway, some companies use verbiage like "Privacy Tones" which adds to the confusion for some people. If you are using a true full CTCSS, it just means you are limited to whom you can hear, but everyone can still hear you. The examples I provided above for DCS are not what actually gets transmitted, but rather a conceptual process to help understand at a very basic level of what occurs, simply to understand the difference. DCS adds a 134.4 bps bitstream to the transmitted audio. To move past concept to the weeds, this video does a great job.

I hate to say it, but sometimes a desired location just doesn't work, regardless of what you do. As an example, there is a repeater I like to talk on that is 35 miles from my VA home, in a North/North-West direction. Due to terrain and atmospheric behavior, if I have my antenna smack in the middle of my driveway, I can work the repeater all day with 1 watt, receive full-quiet, and generally have a great path. Well, if I move the exact same antenna, mast, tripod, etc., 2 feet in any direction, I can no longer hear the repeated and can't bring the repeater up, even with a full 50w. With the antenna mounted on my home's roof, I can hear that repeater and talk on it, but I get poor audio reports and the receive signal is so low that my s-meter doesn't move. It's starting to sound like you may be experiencing a similar issue. Especially because you said if you hold it at an angle in your hand and point it in the repeater's direction. It almost sounds like you are using a crude version troposcatter (oddly just discussing in another thread) to overcome whatever is blocking your signal path. It sounds like its just time to pick a new location.

There is a propagation method called troposcatter that you can use to intentionally talk 300+ mile on UHF, repeatedly and somewhat predictably. If you use high gain parabolic antennas on both ends and aim the beam at the horizon or just above, in the direction of the other target station, the signal scatters off of objects in the atmosphere. A small portion of that scattered signal gets refracted back to earth and heard by the receiving station. Because only a small amount gets refracted, the more power you use and the higherthe gain on the antennas, the higher the likelihood of success. While it does occur in the 450MHz to 500MHz space, the 2 GHz space yields the best success.

If you have a tap and die set, I would add more than the 3 radials to the VHF ground plain to improve performance and help ensure the filters are not overwhelmed. The more radials the better.