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It stands for "Oh, Shit! Over!"

I doubt anyone in Iran would ever accept any wireless devices from any country allied with Israel.

Without knowing what frequencies are being used locally there I think that would be a dumb idea. There are warnings all the time against taking FRS, same frequencies as GMRS, radios on foreign vacations since the frequencies could be used by local fire, police etc. services.

It's a Smith Chart SWR Circle. It's a circle that is drawn centered at the origin frequency, passing through the plotted impedance point. This circle represents a constant SWR through the range. The value where the SWR circle intersects the positive real axis (right side) of the chart indicates the SWR. The closer the red dot is to one of the lines radiating from the right side, the closer to 1:1 the SWR is on that frequency. I tried the TinyVNA and it did not work. It was way off... very inaccurate. A friend of mine (who is a retired RF engineer) uses a SAA-2N VNA when he is in the field. He has great results with it, which is why I went with that specific VNA. It's "good enough" that I would not encourage people who are doing this as a mild hobby to buy a commercial Signal Analyzer. If professionals are using it, the SAA-2N VNA is good enough for me. I have not compared mine to a commercial grade SA, but I have tuned 5 duplexers (UHF and Commercial VHF) with the SAA-2N VNA since I bought it and have had amazing results. With a 2m repeater only having a 600KHz offset, accuracy is extremely critical. My 2m repeater is covering over 8 miles with 5w handheld radios and well over 25 miles with 50w mobiles, and the antenna is only 100' above the ground, 200 feet above average terrain. Those numbers are both further than the theoretical/calculated RF LOS. So, I personally have confidence in the SAA-2N VNA.

Hmmm... never heard of OSO....

Here is a simple to understand description of IP ratings: https://www.iec.ch/ip-ratings The first numeral refers to the protection against solid objects and is rated on a scale from 0 (no protection) to 6 (no ingress of dust). The second numeral rates the enclosure’s protection against liquids and uses a scale from 0 (no protection) to 9 (high-pressure hot water from different angles).

Send them that bug report.

------------------------------------------------------------------------- EDIT: It looks like the duplexer is still failing. Another member pointed out another thread with a similar failure with the same make and model duplexer. While the owner was pushing 70w+ through this 50w duplexer, this may fall into the 'buyer beware' category. If you are going to try it, be sure you stay under the rated limit of 50w for longevity. BTech has it rated for a 50% duty cycle as well. ------------------------------------------------------------------------- Hey folks! For people looking for an affordable duplexer that works well, I may have a solution for you. For those of you who have been following the thread, you may be aware that our friend @LeoG had a problem with a duplexer in his B-Tech repeater. They exchanged it for him, but I offered to take a look at the duplexer, hoping that we could get a spare available, or a second for another machine. I have to say, I am impressed. The duplexer is a SGQ-450D. It is a traditional six cavity mobile duplexer, made in China, and the cost is about $115-$120. When I first got the duplexer, I connected it to a VNA. The unit looked like it was tuned perfectly, the notch and SWR were great... it was just on the wrong frequency, preventing it from working on GMRS. I connected it to a radio and a dummy load, checking both sets of filters, and it worked perfectly. The downfall with duplexers setup like the ones installed in the B-Tech repeaters isn't the duplexer itself, but rather the tuning. What companies do to make these wideband (and what I found with this duplexer), they tune the 3 receive cavities to slightly overlap instead of perfectly align. Also, the 3 transmit cavities to slightly overlap instead of perfectly align. What you end up with is about 500KHz-700KHz of filtering at about 45dB-50dB on each side, for a max of about 100dB of isolation. While not terrible, it leaves a lot of room for improvement, which is easily accomplished if you align all 3 cavities to work on the same frequency. @LeoG asked to have the duplexer aligned to 462.600/467.600. On the high side, I was able to get a minimum of -85dB notch centered at 462.600MHz. On the low side, I was able to get a minimum of -87.4dB notch centered at 467.600MHz. That is better than -172dB of isolation... almost double what the previous tune was. Here are the final tune-up results. Isolation = > -172dB Transmit SWR = 1.08:1 Receive SWR = 1.18:1 Loss due to SWR = 0.0064dB Total Insertion Loss is <1dB For a test, I hooked it up to my portable repeater while at my house. I got the same range as with my personal duplexer. For comparison, these specs are on par with my SinTech/Sinclair duplexer, which is priced 4 times higher than the SGQ-450D. The duplexer will be shipped back to Leo next week. I am looking forward to his real-world feedback after the tune-up. Below are a few images of the duplexer and the tuning results.

Spanish for "bear"

Here's another vid showing a tune of a duplexer on a non vna.

my prayers are with the people of Iran and they are successful in getting their total freedom back they once enjoed.

@marcspaz thank you for the detailed information on tuning the duplexer. We are lucky in that one of our members retired from Sound Solutions and he still has access to all of their equipment. He has tuned all of our duplexers.

Given the present situation, I doubt that the US State Department would ever authorize any such gesture of aid to any country that is hostile to the United States or it's allies.

Very true, but they are very friendly with China.

I think I've finally sourced the issue. I did another firmware update, and completed another factory reset. This fixed the overall issue (so i thought). As I started piecing settings one by one, to try and source any further issues, i found that when you turn on the weather alert the previous issue happens. Once it is off, the radio works as it should.

To answer question about tools used and how to adjust a duplexer, here is a quick overview. Tools I used: Windows PC SAA-2N VNA VNA View software Box Wrench Screw Driver Brass Brush To tune the duplexer, you have to follow a couple of steps. Calibrate the VNA for the frequency you are testing (via the PC or on the VNA, depending on if you are using the PC or not) I typically set the center frequency to the frequency I am tuning for, with a 10MHz spread. From there, we are going to tune either the low side or high side, separately. For this example, we can start on the low side. Connect the S11 cable to the "antenna" port. Connect the S21 cable to the "LOW" port. Put a dummy load on the "High" port. Refer to Image 1. Set the Trace 1 format to S21 Thru. With a mobile UHF cavity duplexer, you can disable the other traces, but if you want to track your SWR at the same time, set Trace 2 format to S11 SWR, and then disable the remaining traces. Adjust your scaling so you can see at least -110dB Adjust each adjustment screw to create the deepest notch possible, to the transmit frequency. In this example, 467.600MHz. only adjust one tuning screw at a time, loosen the jam nut with the box wrench, just enough to allow the tuning screw to move, and while making adjustments, hold the jam nut with the wrench. Typically, once you set the screw to the proper depth, it can be a bit tricky to set the jam nut without turning the screw a bit at the same time. A trick I learned is that I put the screw just a few degrees off, counter clockwise, so as I tighten the jam nut, it snugs the tuning screw into the correct location. See Image 2 and Image 3 From there, switch the S11 cable to High, and the dummy load to the Low side. Repeat the tuning steps for the high side, but tuning the notch to the receive frequency. In this example, 462.600MHz. This guy has a great video on using a VNA to adjust a duplexer. I have no idea who he is, but it it's good content. The only thing I would add is, he stated he is using 200 sweep points. I would use the highest sweep setting you can that provides a good enough resolution of the frequency spread you are tuning. On the VNA itself, I use 401 points, but on the PC, I use 1024 points. https://www.youtube.com/watch?v=TbEK4v_3Xuo With this duplexer, specifically, the tuning screws are brass. Either the manufacturer or B-Tech spray painted the tuning slugs. I had to spend a bit of time cleaning the paint off the screw threads and heads with a brass cleaning brush to make it so the duplexer could be tuned. If you have a situation like this and want to repaint the screws for cosmetic reasons, be sure to use non-metallic paint, such as Krylon Fusion for Plastic. It must be non-metallic, polyurethane free, and lead free. I am including a few extra pictures displaying the results. Image 1 Image 2 Image 3

He lied to you. He lied, right to your face.. That is not a GMRS radio and it is the LAST thing anyone with a brain would recommend to someone "new to GMRS" and looking for a GMRS radio. You should never listen to anything that idiot ever tells you again.

Right around 8v. The one I pulled out of the box was at 7.5v and is currently charging. Bumped up to 7.7v on the included charger. I'll test it again and post photos when it's done charging (maybe in the morning depending on when it's done).

@WSIA835 They did not charge money when they sent me warranty replacements. First warranty radio came from a warehouse up in NY or NJ, second radio came from Amazon (ha).

I won't wish that on anyone. Barf Wang radios need to stay in Pandaland.

GMRS freqs are not universal. GMRS freqs in one country could be used for another radio service in another country. For an example, allocated public safety freqs in the US are the same freqs used for business radio services in England. No country in there right mind will send anything that could benefit the political division or military operation of an adversary. Iran may be in the world of hurt for radio communication or they may think any civilian operation could be considered an opposition force, may take away those gifted radios. Humanitarian items of medical and food would be a more appropriate. Electronic devices would never be approved by this country, nor they should be approved. Anyways, regardless of the freqs that could be used for by citizens in Iran, do you really think they would really work? Not a chance in hell they would work with all the electronic jamming going on.

I just did the clearing thing and no change. Thank You for reporting it, again!

Well, we can hope…. It worked so well in Afghanistan, Iraq, Vietnam, etc. Syria was different because the U.S. wasn’t overtly involved. It stands a good chance of succeeding.

You need to clear your cache. No, I’m wrong. Although it isn’t jumbled for me, the home page is asking me to create a new password again. I’ll report it again.

My first Duplexer from BuyTwoWay covered the entire GMRS Band and my repeater then was on Ch 22. I had a terrible experience with it, ended up buying a tuned dublexer tuned for Ch 18 and moved there.. Been working great since.. I sent the original duplexer back to BuyTwoWay and had them tune for CH 18 to use for my portable repeater which i mounted to the outside of a FAT 50 Ammo Can. Since this portable set up gets moved around a lot, i'm always concerned that the duplexer will get knocked off tune, but going to almost 3 years now its holding tight on Ch 18.. I did try to tune it myself as Marc did, but didn't have such luck or patience.

Humanitarian efforts are just that and should be given without political consideration. It's not the people of the country that is the problem, it's their government. I work with an Iranian and he has told me stories of what goes on over there. Trust me, most people over there really don't believe in what they have to live under. If cheap GMRS radios can help the cause it shouldn't matter which country assists in humanitarian aid.

The 905G is not CHIRP capable although the wouxun software works fine, but if you plan on getting more radios and wish to copy paste between, the CHIRP is your friend there. The 805 is CHIRP capable. .The cable you want is readily available almost anywhere, Amazon or buytwowayradios.com those will work with the 935,905,805 or almost any other radio or radio brand with a std k1 connector. I would suggest buying not from Amazon as Amazon is rife with crappy knockoffs of this type of equipment that uses perhaps questionable driver or just plain won't work. 805 is IP55, 905 is IP66, 935's are IP66. 55 means dust protected and can resist water jets. 66 means dust tite and can resist powerful water jets. I have a yeseau that is IP55 and I've dropped it in a stream, it was not affected. I've also had a 935 fall off my sxs in my back 40 and lay in a puddle for a month, been run over a few times before I found it, it was not affected at all. So anything IP55 or above would be just fine for heavy outdoor use in snow, rain.

More waterproof.

No experience with that radio. That is a HAM radio that appears to be capable of transmitting on GMRS (otherwise may be known as a SHTF radio). It has a boatload of features that cater to HAM's and are not readily understandable on how to use/configure or even what they are for novice radio users. To transmit on GMRS you would have to manually program all the regular GMRS channels/frequencies. (of course adhering to power limits etc for those channels, if you care about conforming to rules). All the GMRS rules/frequencies are baked in on a true GMRS radio. It is also not CHIRP capable which was one of your listed requirements. (Vero N76=Radioddity GA-5WB also not CHIRP capable) More is needed to recommend anything, but just throwing out Mabey a Wouxun KG-805G ? It's a good true GMRS radio, very easy to use. And mid-price range..CHIRP capable. I prefer the 905G as it has a bit better IP rating but it is not CHIRP capable.

All my contacts with customer support for Tidradio have been positive. They've never told me no we won't replace it. And they've never asked for the old one to be returned.

Welcome!

There's no advantage; you could just get a UV5R.

There are a few repeaters in my area that I have requested access. One of them I requested access twice in a year and a half (private repeater). The owner states that you have to give him certain information including a valid phone number so he can conduct a phone interview. Of course, I never heard from the owner. I don't care enough to look into it more. The rules for requesting access was a red flag but I tried anyway. On the other hand I have requested access on some other repeaters, not in my area, and received permission in a day or two. If there is an open repeater listed, with tones, that requires you to request access and I don't hear from the owner I will just use the repeater. If questioned by the owner I will then ask permission on the air. That has never happened. I don't understand why there are still owners that have repeaters listed as open, with the tones listed, yet they still want you to request access. I don't tend to play well with others and my use of radio is to make quick contact with people I know for a specific purpose. If repeater owners go the route of drama I don't get mad, I just erase the info from my radio and move on. It is their machine so they can have their rules. On the HAM side, if some moron wants to critique my radio usage I just finish my transmission and ignore them. I don't use radio, Amateur or GMRS, for meeting random basement dwellers in the darkest hours of the night so I don't really run into those type of repeater people very often. Don't take it too seriously.

Even though they don't call it GMRS in Iran this is the perfect situation to offer cheap disposable GMRS radios to the rescue workers to facilitate efficient communications.

I use the UV-9R PRO on our ranch & range and they work great. They work with chirp also. Features： IP67 waterproof and dustproof High & Mid &Low Power Switchover Battery Saving VOX Function Auto-Back Light Time-out Timer (TOT) 50 CTCSS and 104 DCS Codes Voice Prompt ANI Code PC or Manual Program DTMF Code PTT-ID ATUO Keypad Lock Busy Channel Lock Function Dual Display and Dual Standby Emergency Alarm Priory Scanning Function Relay Forwarding Confirmed (1750 HZ) Low Battery Warning U/V Cross Band Dual Watch

thank you for the advise I was talking to someone who dabbles in radio and is pretty knowledgeable in radios. he told me to look into VR-N76 radio pretty easy to use etc. have you heard or know much about them?