RickW

I have mentioned it before, but it still surprised me when my wife and I did some testing a few years ago. I have a GP-9 on a 40 ft tower at our ridge farm which is 1240 ASL and I drove my vehicle way down to the nearby Sidie Hollow, which is less than 900 ASL. These are deeply notched valleys (called coulees) in the Driftless Area of Wisconsin. Distance back to the farm was around 3 miles. With a cheap dual band 2 mtr/440 ham antenna retuned for GMRS, we could barely communicate. Switching to the tiny Midland mag mount 6 inch quarter wave, the signals became quite readable and one bar on the Midland MXT400's which we had on each end, running low power. Switching to the Midland mag mount with the "3 db" gain Midland 5/8 wave antenna increased it to another bar. Switching to the "6 db" gain Midland 5/8 over 5/8 wave increased it to another bar. I think we compared power levels from the lowest power setting to medium and that helped as well. I really did not expect to see that much of a difference. Especially when you consider that the gain antennas tend to put more signal closer to the horizon. It may be that the RF was bouncing around the hills and sort of filling in from different directions. I have no way of measuring the difference in db's for each bar. It would be helpful to have a ballpark number.

Perhaps this is a bit off subject, but over the years I tried various ways of getting some height with various home made supports. I wanted something that I could handle by myself. One of my current supports is a treated 4 x 4 post at least 3 feet in the ground (or more) and back filled in with gravel.It is out of the ground around 6 + feet, but low enough so that I could reach the top when standing firmly on the ground. About a foot from the top of the post I attached two 10 foot ~ 2+ inch pvc pipes with a long bolt through one pvc, then the post and then the other pvc to make a hinge. Another long bolt close to the top of the post to firmly attach the pvc pipes to the post. By pulling one of the bolts, I can lower the pvc pipes to the ground. Then I used a fiberglass tube, a bit more than 10 feet long and attached it with two bolts to the top of the two pvc pipes which are now much closer together than where they are attached to the post down below. This gives me well over 20 feet. Because I experimented with many ham antennas on many different (mostly) HF frequencies over the decades I found that this support works as well as, or actually, better than, the typical expensive commercial vertical such as the Butternut HF-XV series. I can run parallel wires for different bands and top the fiberglass part with a CB whip which just made it to 33 feet at the tip. That gives me 40 meters. Then shorter wires for other bands, such as 20, and 30. Because this is effectively a vertical HF antenna, it needs radials, so I put down a bit over 30 radials with some at 30 and some up to 100 feet long. The antenna is around 150 south of the house and I put it that far out because of the radiation pattern impinging on the house and the clearance for the radials. I have swapped out the home made antenna with a Butternut, and after a number of years, put the home made support back. With the Butternut, which is much shorter, I had to use some guys as the antennas is not robustly made. I do not use guys with the home made support although being on the ridge here in the driftless area of Wisconsin we get a lot of wind and the support does tend to lean away from the SW. Using pvc for both the bottom and top sections I found to be too flimsy, thus the fiberglass tube. You could also use EMT or aluminum tubing. For GMRS use, you would want to have the post much closer to the house to keep feedline loss to a minimum. Since the GMRS antennas are so lightweight, they would not be too much of a load, even a gain vertical. I might mention that what I use for GMRS antenna support is 30 feet of Rohn 25G plus another 10 foot pipe. This has a house bracket at 12 feet on the end of the garage. No guys.

TYT is a brand. The term CCR is an acronym for Cheap Chinese Radios and is used as a criticism for the lower cost products coming from Asia. A number of the folks here do not consider them to be of adequate quality. I have Midland MXT400's and use one for base and one for my vehicle. I also have two MXT115's in several other vehicles. For HT's, I have two BTech GMRS V1's and two Wouxun KG-805G's. Each radio has trade offs, but they all seem to work fairly well. I have compared them to my ham equipment, (such as the ICOM IC-7000) and the receive sensitivity seems comparable. The BTechs had some quality control problems and the replacement also has a defect but I am just going to live with it since it does not seem to degrade the GMRS function. (It is just that the FM radio function will not work and I actually find this useful). The big issue with the Midlands, and something that I completely overlooked when I bought them, is that they can only transmit and receive the same set of CTCSS (PL) tones or the same DTSS tones. You can not have one analog PL tone for TX and a digital DTSS tone for RX. What ever tone you set, it is always on for both TX and RX. Of course, if you are primarily using the equipment for simplex, then this is not really a problem. Midland sells some decent HT's but they do not seem to work at all with repeaters so the company is a bit behind the times in supporting GMRS.

We have two of the B-Tech GMRS V1 units and 2 MXT400's and 2 MXT 115's. The main concern some have is that the Midland units are narrow band only, but this has been OK for personal use. Most GMRS repeaters appear to be wide bandwidth, One time I tried using the Midland "compander" and that helped the receiving station with my modulation, but then their modulation to me was more distorted. The B-Tech units can work with wide or narrow. I have ordered a couple of Wouxun 805G HT's as I wanted to try them out. If they had been available earlier I would not have purchased the B-Techs because of the quality control issues with B-Tech, the fact you can not talk to anyone on the phone, and the fact that back up batter packs are AAA. The Wouxun are repurposed KG-UVD1P's and locked down to meet Part 95E rules and use AA batteries. They are also 4 watts while the B-Techs, which used to be 4 or 5 watts, have been reduced to 2 watts. The difference in power can be useful in some situations, but antennas and line of sight is the most important. There are some helpful youtube videos, although one has to be careful because of a fair amount of misinformation. I tend to make comments on those videos and in a nice way, try and make appropriate corrections or explanations. GMRS can be iffy for a contact since there are not many who monitor for calls for help. I am probably an exception in my area but I have a reasonably high gain antenna and high location on our farm and being retired helps. I can talk to folks using FRS HTs for many miles away (10 or so in some cases if they are close to the ridge). When I have rarely tried a repeater, I have chatted a few times when I actually did not expect anyone to be there.

I came across a short (under 4 min) professionally made video showing how citizens in fire prone areas took action to have some kind of communication network. This came about because of the horrific fires in rural areas and loss of telephone and cellphones. https://www.youtube.com/watch?v=2uhOwng_j38 The solution was to purchase GMRS radios and apparently quite a few where sold in just one rural area. They had some help from what looks like a ham or two (but did not identify them as such), and even set up a modest repeater to get across one ridge area. The equipment shown were Midland MXT series radios. And for this application, I think this is a good choice for plug and play.

Perhpas it is a minor point, but the FCC changed the Subpart from A to E when they did the 2017 rewrite of the rules. Thus, Part 95E refers to GMRS.

Berkinet had mentioned that: "GMRS power output limits are specified as power output from the radio (I.e. at the antenna connector) rather than ERP." Based upon 95.1767 GMRS transmitting power limits, here is how I understand the rules and hopefully explains my earlier comments: On the eight main/repeater 462/467 channels 15-22, GMRS stations are allowed to operate up to 50 watts output. On the seven 462 interstitial channels 1-7, GMRS mobile, hand-held portable and base stations must not exceed 5 watts ERP. On the 467 interstitial channels 8-14, only hand-held portable GMRS units may be used and they must not exceed 0.5 watts ERP. That is why channels 8-14 would not be found on legal GMRS mobile and base rigs since that type of equipment are not allowed on those channels. The hand-held units are allowed to operate on those channels under GMRS rules. Even on the seven 462 interstitial channels 1-7, many of us may be exceeding the ERP levels since we may use higher gain antennas with low loss feedlines and I suspect most transmitters are typically preset for 5 watts output. I wish the FCC had allowed GMRS stations to always use output power. Imagine how difficult this is to understand for the casual GMRS operator. This is why we tend to operate on the main channels when using GMRS equipment.

I might mention that though GMRS and FRS can interoperate, not all types of GMRS equipment can do this on all of the 22 channels. If you have a base or mobile unit on GMRS, you will likely find that the equipment does not have the 467 MHz interstitial channels 8-14. The rules specify that those channels can only be used by handheld portable units. And it makes sense because those channels are limited to 500 milliwatts ERP. We stay on one of the 8 main 462 MHz channels when operating simplex since we can transmit up to 50 watts output. Even on the 462 MHz interstitial channels 1 - 7, we are probably exceeding power levels at times since even GMRS radios are only allowed 5 watts ERP. With a modest gain antenna it would be possible to exceed 5 watts ERP if your output was 5 watts. On the 8 main channels you do not have an ERP limit for GMRS. Of course, FRS always has an ERP maximum allowable power level, but that is easy to do considering the fixed built-in antenna. My thinking is that if I had FRS equipment, and I wanted to limit the distance the signals can travel, the use of the 500 mw channels might offer better security. This could be useful for close-in groups or especially for preppers.

There have been some very good comments on GMRS/FRS. I have probably mentioned this before, but if you want to have backup communications, especially for families, GMRS is one of the best ways that I have seen. Because GMRS and FRS and pretty much interoperable, that does create some downsides if you have someone running higher power GMRS equipment, especially with the allowance of external/gain antennas and they are not licensed, you can not easily determine this. For rural families that may not have the best cellphone coverage, GMRS can be useful. Even though retired, we continue to live on our small farm, but if we were large enough to need other workers, it would be possible to use a GMRS license for the family members and HT's for non-family. This would allow a good base station to mobile/portables. This could also work for any small family business that may have a few workers who are not part of the family. While there is not much activity on GMRS, there are commercial users of FRS. This past year I kept hearing stations talking back and forth and it sounded like they were loading something. Comments went on like "OK, Joe, a little further, oops too far, back off, OK that is good right there." And this would go on for long periods. I finally found out that these were fiber optic installers who were working along my ridge. My base antenna is a gain GP-9 at 40 feet so gets good distance. I have talked to hunters over 10 miles away if there were close to the ridge. If I monitor MURS frequencies I can pick up some of the Walmart channel five users at times. They must have to be in certain locations to make that work over the 7+ miles distance. For a lot of off road folks, it seems like MURS would be pretty good if you did not want to get any license. And now we are finally seeing some legal MURS radios that are reasonably priced. In a really serious emergency, without any planning ahead of time, I suspect CB will be useful because so many folks have them. I wish they would have SSB, as we do, but that is not common. There are SSB CB nets in my area, but most of the stations are very weak except one ham about 20 miles away. He is net control for one night a week so I check in there from time to time. Or talk to him on 2 meter FM. Realistically, most people just do not want to study for an amateur radio license. At one time my daughter had her Technician Class (she accidentally let it expire) and my wife and I still keep our Amateur Extra Class licenses, but rarely use them anymore. No one else in our family has the slightest interest in ham radio.

Had an embarrassing thing happen last year. I had installed a GP-9 antenna (three sections) only 2 or 3 years ago and one day I looked up and saw the top section wire just hanging loose in the wind. The top fiberglass radome had fallen to the ground. At first I thought it was all over for that antenna, but I took it down and except for a slight bit of chipping on one of the molded plastic inserts that helps the wire maintain its complicated folded positions, it seemed to be reasonably intact. It did not snap the wire, but if I had let it swing around for much longer it likely would have. I put it back together and screwed the top back on.This time I wound several turns of good quality electrical tape (Scotch 88 I think) over the joint of the top and middle section after securely screwing them together. Same with the still intact lower to mid section joint. I would not again install such an antenna without using some kind of tape or heat shrink to insure it can not come undone. There is a gasket to seal the sections, so I was not worried about any water ingress. Antenna seems to work about as well as before. I use if for GMRS, even though it is not ideal because the SWR approaches 2:1 on the 467 MHz channels.

I tried making the aforementioned resetting to no avail. It is getting more difficult to recommend these units as I had hoped they would have better QC.

I have had a couple of BTech GMRS V1 HT's for a year and they seemed OK and work well with our Midland MXT 115's and MXT 400's. Just before the warranty ran out I noticed that one of the units had a dead battery, even though the power switch had been off. I charged it back up and noticed that over a three day period it drained the battery with the switch off. Thinking the battery was defective, I put in a warranty RMS and was just about to send it back when I got to thinking that maybe it wasn't the battery, but maybe it was somehow drawing current when off. So I set up a current flow test between the batter and rig and sure enough there was a continuous 15 ma. discharge. So I got another RMS and sent both the unit and the battery to BTech. They replaced both in short order. Then I discovered that the replacement unit did not have the FM radio receive function. I actually find this useful as another use for the radio. Upon contacting BTech, they indicated that I needed to enable the function with CHIRP. I ordered the cable and it turns out that the FM function is enabled, so something else is defective. I wrote to them several times but they are not very good about responding but finally asked me to request another RMA. I tried that but by then the warranty period had run out and the system would not let me request an RMA due to being out of warranty. So I again asked them about this and they said to "edit the date on the RMA." It costs around $7 or so to mail these units to BTech and I am considering just living with the disabled FM function. Hopefully no other problems exist that I have not noticed, but it has been disappointing. I am thinking that it is possible that this replacement unit may have a physical issue with the button not engaging the internal switch that switches the FM function but I am hesitant to disassemble it. Has anyone else had a problem like this? And/or has anyone tried taking one of these units apart? Thanks for any help. Rick

Some time back I had posted my experience with four different antennas from an intentionally marginal location which was several miles from the home base and hundreds of feet lower in elevation, using Midland MXT400's at each end (running at mid power setting) and and with a GP-9 2m/440 ham antenna at 40 feet on our ridge top farm base location. The GP-9 is not optimum for GMRS due to being quite a bit off the design frequency and has nearly 2:1 SWR on the 467 channels but reasonable SWR on the 462 channels helped by the coax loss of course. Results surprised me somewhat: - 2m/440 ham antenna retuned for GMRS generally showed one bar on transmit and receive - 6" Midland stock mag mount quarter wave showed two bars and much better signal copy - so called 3 dB Midland NMO antenna showed three bars - so called 6 dB Midland NMO antenna showed four bars I read that at least one person had problems with the 6 dB antenna melting the center coil, but so far we have not had that happen with only limited transmission time when mobile. We use Midland magnetic NMO mounts on our vehicles. My wife has the MXT115 with the 3 dB antenna on top of her Equinox SUV and I have the MXT400 with the 6 dB antenna on my Malibu rear trunk lid so that we can clear the garage door. Range between vehicles is several miles and not that much different than when we used simplex on 2 meters when we use ham equipment.

I have been wondering how users tuned up the cavities, say 40 to 50 years ago when some of us OT's started using repeaters? Most ham repeaters had some procedures to do this without multi thousand dollar service monitors. I recall some local hams making cavities from large diameter copper tubing and maybe was even silver plated internally. I see some info on repeater builders, but have any forum members done cavity tuning without a service monitor/spectrum analyzer? If a person made or bought a repeater for GMRS, and then added a commercial duplexer, particularly the very low cost "portable" duplexers, and needed to change channels or to tweak the duplexer, how practical is it to tune it yourself and what is the absolute minimum equipment you would need?

Some manufacturers use the theoretical isotropic antenna as a baseline and then compare their antenna to the isotropic. If they are honest they will specify their antenna gain in dBi. A dipole antenna has a gain of 2.15 dB above the isotropic and some manufacturers use the dipole as the baseline and specify their antenna gain in dBd. You can subtract 2.15 dB from dBi gain to match up with the dBd gain. Another consideration with gain is that it depends upon the angle of radiation. Some antennas may radiate with rather high angles, such as using a quarter wave vertical on the third harmonic which can give you a fairly close match. A good example being a 2 meter ham antenna being also used as a 440 MHz antenna. Even though the match might be reasonable, this type of antenna will have a higher angle of radiation on the odd harmonic and may not be as useful for VHF and higher frequencies, especially on flat land. The manufacturer could claim this level of gain without being specific as to the angle and makes the antenna appear to have higher gain than you might expect. There are cases where a higher angle might work better, such as if you were in a deep valley and wanted to communicate with a station at a higher elevation. But, most of the time we want the antenna to radiate toward the horizon for maximum communications distance.