Lscott

Looks like it's about the same thing as the Kenwood TK-3360's. They even look similar. Kenwood's TK-2360/3360 https://www.kenwood.com/usa/Support/pdf/TK-2360_3360.pdf Motorola's CP200 base model https://bearcom.com/media/catalog/product/files/cp200xls.pdf

The point about using CCR’s as an entry to the radio hobby, because it’s low cost, until one figures out if they really like it or not is valid. However the flip side of the coin has to do with real world performance. Most of the CCR’s perform poorly in the receiver section, low sensitivity, susceptible to overloading, poor selectively etc. A newbie, with no prior two way radio experience, their poor perception of radio communications is due to the budget priced radios poor performance and not really a representative example. That alone may convince them it’s not worth continuing down the road all because of a poor choice of equipment to start out with, and they don’t even know it.

No. The J-Pole antenna is a 1/2 wave length long for the radiating section. The end of the antenna has a rather high impedance making for a very poor match to 50 ohm coax. Thus the extra length is due to an additional 1/4 wave matching section, the section with the short length of extra conductor parallel to the long one, where the tap point selected yields the desired 50 ohms. The overall length will be closer to 3/4 wave length long. At 462MHz the wave length is about 64.7 cm (25.8 inches) and 3/4's of that would be 19.1 inches, just what you measured. http://www.ka3pmw.com/files/jpole_presentation_rev2.pdf

Good point. If Wouxun is not supporting their vendors then as a user what kind of support will one see from the vendor with warranty issues? It would be easy to say send it back to China because we can't support it anymore. As a customer with a problem radio does one want to get stuck in the middle of a dispute between the manufacture and their local sales/service rep's? Anyway it's another data point to consider when making a purchasing decision.

Somebody is not having a good experience with Wouxun radios. http://www.wouxun.us/index.php

How about looking at these handhelds? https://www.ebay.com/itm/184489981820 I have several of them and they work great for GMRS. The battery packs are cheap and easy to find along with the accessories, programming cable and software. The software will work on Win 10 BTW. https://mra-raycom.c...ct-Brochure.pdf They are also Part 95A certified, old FCC GMRS section, and are fine under the new rules. https://fccid.io/ALH29473110

Are you sure about the frequency, 152.625, because that's not one of the offical MURS channels.

My wild guess is the radio was modified to use an external speaker. The switch would have been used to select between the internal one and the external speaker, maybe both.

https://mra-raycom.com/wp-content/uploads/simple-file-list/Specifications/portables/TK-270G-370G-Product-Brochure.pdf https://fccid.io/ALH29473110

If somebody wants a really good GMRS radio these are a good one. https://www.ebay.com/itm/184489981820 I have several myself and they’re solid performers.

Looks like the link for the LFP batteries didn't make it. It's below. https://www.bioennopower.com/collections/12v-series-lifepo4-batteries

I have several LFP, Lithium Iron Phosphate, batteries. Gave up on any type of Lead Acid since they tend to get wrecked if you don't keep them on a battery tender at all times to trickle charge. The LFP's can be charged up and sit around for months or longer, great for emergency use, and they don't discharge hardly at all. In fact for long term storage it's recommended NOT to fully charge them. Try that with a Lead Acid type and you will kill it. The LFP batteries have a higher terminal voltage, around 13.3 VDC to 13.4 VDC when charged making them a better match to mobile equipment that expects a nominal 13.8 VDC. When the battery is nearly discharged, 90 plus percent, the terminal voltage is still around 12.8 VDC more or less. A Lead Acid battery is around 12 VDC when its at 50 percent capacity. Most mobile equipment spec's 13.8 VDC at +/- 15 percent so the low voltage cut off is at 11.5 VDC. You won't get most of the capacity out of a Lead Acid battery before the electronics starts to shut down or misbehave. The down side to LFP batteries is the cost and you need a special LFP charger for them. If you do buy a battery make sure you get a charger for it. I also have several MPPT charge controllers for solar panels. The charge controllers are used to keep the battery packs up. The link below is for a company that is friendly to two-way radio users for batteries and chargers. I have one of the 6 amp-hour packs for portable handheld radios and one of the 40 amp-hour ones for fixed location use. The charge controllers I have are from this company below. I have several of the GV-5 charge controllers for LFP batteries. https://sunforgellc.com/genasun/#gen_product_row The company below has decent prices on solar panels. I have a couple of the 50 watt, one 30 watt, and a couple of the 10 watt mono crystalline panels. https://www.renogy.com/solar-panels/ If anybody has a need for a pure sine wave inverter this company has some good products. I have the 300 watt version with a builtin GFI. https://gpelectric.com/product-category/inverters/pure-sine-wave-inverters/ For connections I use Anderson Power Pole connectors. A good source is from Powerwerx. Also one or two of the DC inline power meters comes in handy too. https://powerwerx.com/anderson-power-powerpole-sb-connectors https://powerwerx.com/watt-meter-analyzer-inline-dc-powerpole

Just a note about that. I've had very good luck using toothpaste to polish up the plastic screen on several radios I got used. I got scratches out I thought would never clean up. It takes a lot of work to rub out the scratches, toothpaste is a VERY mild abrasive. I used it straight from the tube on a paper towel while using a fair amount of pressure. Tilting the radio so the light reflects off the surface is a very good test to see how the polishing is going. I wipe the screen down with a wet paper towel first so I can get a clear view of the surface. At the end I sometimes use an electric toothbrush to do the final polishing. I did spend about an hour or more on the more damaged screens. On several radios when I got done the screens could have passed for new if you didn't do a real detailed examination. If you can't get a replacement case or don't want to spend the money the above procedure works well. Nothing like getting a used radio at a good deal, then clean it up where it looks almost new. 8-))

1. Yes you need fuses of the proper type and amp rating. Too low in amp rating the fuse will fail during transmit, which draws the most power. Look at the radio's manual. The recommended fuse and rating is typically specified there. 2. You can try some automotive trailer power connectors. You can get something like the below cable and plug. https://www.amazon.com/807-Extension-Disconnect-Harness-Connector/dp/B07SQ1G56V (You most likely can find something like this at your local auto supply shop) Just cut the cable in half. Connect the wire end to the power supply, or battery, observing the proper colors, red is positive and black is negative. Then use the other half of the cut cable for the radio doing the same thing matching the red for red and black for black. The bonus is if you get two cables and cut them in half the second one can be wired into the automotive electrical system. Now you can freely move the radio between the vehicle and the house, for example, without having to worry about screwing up the wiring and wrecking the radio. I highly recommend you permanently attach the wires to the power supply/battery and radio then use just the plug. Sooner or later you'll screw up and connect the radio up backwards. When the "magic smoke" comes out of the radio it quits working and there is noway to put it back in either. 8-(

One other point that hasn't been mentioned before in this thread is the following. Since the original post requested recommendations for radios, and the usage will be in a farm setting, the physical construction and reliability will be very important. The radio(s) will likely get exposed to rain, fine dirt/dust in the air and likely dropped on soft and hard surfaces too. Many of the cheaper radios will fail. Just about all of the old LMR/commercial radios are designed for just this kind of environment. For example, I just got a used Kenwood TK-3170-K radio off of eBay, the seller took my offer of $15 when contacted by eBay's messaging system, with free shipping. The photos showed a nearly completely destroyed antenna on a radio with painted on ID and covered with dried up fine dirt/dust from being used outdoors most likely. When I got it I spent over an hour with a brush, q-tips, old tooth brush, safety pin, counter cleaner and alcohol cleaning it while using the safety pin to dig out the caked up dirt stuck in narrow cracks around the edge of the case. Once clean it looked OK with minor scuffs and a few scratches but programed fine. On air testing showed the radio was fully functional with a good battery pack and a new after market antenna. I very seriously doubt most of the cheap handheld GMRS radios being sold would have survived what this radio went through. eBay item number: 114446054336 While the RF performance of the radio is very important it still has to survive. A radio with great spec's is worthless if it breaks.

Yes, I’ve had that experience. It’s even worse on the Ham bands with DMR when stations don’t get their audio levels set right. Then there is the flip side too. North of my area there is a GMRS wide area coverage repeater specifically setup for narrow band operation. I contacted the owner and had him verify it was in fact narrow band. My guess is that’s all he had or just acknowledging more users are using narrow band radios. At least with my Kenwood handhelds I can program the bandwidth for normal/narrow on a per channel basis. The radios I use have 128 channels so I program one set for normal FM and the other for narrow band. At least this helps to reduce the annoying sound level mismatch with more that two stations on frequency when the other station is stuck with one or the other bandwidths. https://mygmrs.com/view?id=3768

I agree. Just because this is a GMRS forum doesn't mean it is the best solution for his requirements. This should be a healthy environment where other options can be suggested.

I did some snooping around and located some info on the Aerotron radio. Not much to see. Just had to check it out. https://fccid.io/APC9RB60ACC25B The interesting part is besides doing SSB it also had some sort of digital mode. Also the frequency tolerance is far better than the usual FM radio. Part 74 https://ecfr.io/Title-47/pt47.4.74 Part 9 https://ecfr.io/Title-47/pt47.1.9

Thanks for the info. I never heard of this radio before. The description of the method to hold the frequency centered on the channels using a pilot tone brings up a question. I'm assuming they used the pilot tone in a PLL circuit to adjust the TX/RX frequency until the tone was exactly in the filter's pass band? The pass band of that filter would need to be rather narrow too I assume.

Thanks. I was sort of expecting that kind of result. Given the usual crystal reference frequency accuracy and temperature stability makes it difficult to stay on frequency. Being off frequency by 100 Hz or so SSB signals are petty much unreadable.

My goal here was to find out if there is currently, or in the past any LMR/Part 90 radios that could in fact do SSB.

No, that shouldn't happen. On SSB the bandwidth can be rather narrow. On my old ICOM IC706MKIIG I had a optional narrow SSB filter installed. Many Hams run a 2.2 KHz to 2.4 KHz bandwidth, or a bit more. SSB is more spectrum efficient than FM, at lest for the typical bandwidths being used. https://www.dxengineering.com/parts/ico-fl-223 The above radio opens up a lot. http://www.catlog.net/_Descarregas/Manuals/01-Icom/Icom%20706MKIIG%20OBM.pdf Yes the FT991A you can only open up the HF section. http://blog.pauls.li/wp-content/uploads/2015/01/FT-991_MARS_Mod.pdf So far nobody has found a general way to open the VHF and UHF bands. There is a way to do it on a per frequency basis however using a test mode from what I've found. https://forums.qrz.com/index.php?threads/ft-991a-expanded-tx-on-vhf-uhf.623521/

Looking over the rules the FCC allows several types of emissions, modes, on GMRS: 95.1771 - GMRS emission types. 95.1787 - GMRS additional requirements. https://en.wikipedia.org/wiki/Types_of_radio_emissions https://www.law.cornell.edu/cfr/text/47/95.1771 A1D: Double-sideband amplitude modulation One channel containing digital information, no subcarrier Data transmission, telemetry or telecommand (remote control) F1D: Frequency modulation One channel containing digital information, no subcarrier Data transmission, telemetry or telecommand (remote control) H1D: Single-sideband with full carrier One channel containing digital information, no subcarrier Data transmission, telemetry or telecommand (remote control) J1D: Single-sideband with suppressed carrier One channel containing digital information, no subcarrier Data transmission, telemetry or telecommand (remote control) R1D: Single-sideband with reduced or variable carrier One channel containing digital information, no subcarrier Data transmission, telemetry or telecommand (remote control) F3E: Frequency modulation One channel containing analog information Telephony (voice intended to be listened to by a human) G3E: Phase modulation One channel containing analog information Telephony (voice intended to be listened to by a human) H3E: Single-sideband with full carrier One channel containing analog information Telephony (voice intended to be listened to by a human) J3E: Single-sideband with suppressed carrier One channel containing analog information Telephony (voice intended to be listened to by a human) R3E: Single-sideband with reduced or variable carrier One channel containing analog information Telephony (voice intended to be listened to by a human) F2D: frequency modulation One channel containing digital information, using a subcarrier Data transmission, telemetry or telecommand (remote control) G2D: Phase modulation One channel containing digital information, using a subcarrier Data transmission, telemetry or telecommand (remote control) The interesting one is running SSB. Has anybody run across a Part 90 certified radio that can do SSB on the GMRS frequencies? If the FCC seems to be "OK" with Part 90 LMR radios on GMRS would they have a problem with one doing SSB? At least the emission mode is allowed, J3E.

The following link is a test of one of those cheap Chinese “notch-plexers” you see being sold. You can buy them from the same source as the bandpass filter. They sell for around $100 depending on power requirements. Used with a couple of “clean” HT’s and a simple duplex repeater controller makes for a cheap repeater for noncritical locations. This is basically what’s in that Retivis repeater being discussed elsewhere on the forum. What I like was the temperature testing to see how “stable” they are. People forget the cavities change dimensions with temperature thus the tuning will change. http://www.repeater-builder.com/antenna/pdf/chinese-mobile-duplexer-measurements.pdf

Normally the power loss in a good quality RF connector is rather small, a few tenth's of a db. What you do have more of a problem with is with the impedance of the connector. The common PL-259/SO-239 are noway even close to 50 ohms. At UHF this impedance mismatch can cause elevated SWR, more reflected power. The general advice is to use constant impedance type RF connectors. For GMRS the typical one recommended is the "N" type. There are other common constant impedance connectors you will likely encounter, SMA and BNC. You do have to watch which impedance the connector is designed for. They are commonly available in either 50 ohm or 75 ohm versions. For GMRS and the usual 50 ohm coax you need the 50 ohm version of the connectors. You can't simply look at them to tell the difference, the physical dimensions are similar. If anybody is interested in the whole issue of coax cables, matching, RF connectors etc. the following guide has a lot of useful info. https://www.fclane.com/sites/default/files/rfguideen.pdf