Lscott

That's likely one of the real reasons why it isn't tried. Most of the digital modes have fairly wide signals compared to side band. A SSB signal is around 3KHz, correct, while some of the digital mode signals are like the following examples: 4K00F1E – NXDN 6.25KHz digital voice (IDAS, NEXEDGE) 4K00F1E – dPMR 6.25KHz digital voice (Typically not used in North America, used in the EU) 7K60FXE – 2-slot DMR (Motorola MOTOTRBO) TDMA voice 8K10F1E – P25 Phase 1 C4FM voice 8K30F1E – NXDN 12.5KHz digital voice (Wide DAS, NEXEDGE) 9K36F7W – Yaesu System Fusion C4FM (Voice Wide) 22K0D7E – TETRA DMO Voice Some of those linear translators don't have that much bandwidth to begin with. Using digital isn't going to be welcomed and very highly discouraged, not because it can't be done with the right equipment. As I said before any signal that's transmitted is always an analog type regardless of what information is being sent. The main difference is how the signal is shaped. Simple rectangular pulses are not sent because the bandwidth required is stupid wide. Various types of pulse shaping is used. One such shape is GMSK. There are others with different properties. https://www.oscium.com/sites/default/files/WhitePaper_Simple_Signal_Shaper_GFSK.pdf http://www.sss-mag.com/pdf/gmsk_tut.pdf https://www.researchgate.net/profile/Thierry-Turletti/publication/2575678_GMSK_in_a_nutshell/links/0deec517e72247f39d000000/GMSK-in-a-nutshell.pdf?origin=publication_detail I get the point about possible signal inversion occurring in a linear translator. However that would depend on the design. I would guess not all of then do so. That how the convention between using upper or lower side band on HF originated, selecting the high or low side mixing product of the VFO with the local oscillator depending on the band. Also likely the reason why simply connecting the output from a receiver's discriminator to a transmitter's modulator might not work has to do with the frequency accuracy. With 4FSK it's critical the frequency shifts are right. Being off too much the RX radio can't decode the data. That means the level being fed into the transmitter's modulator has to be very carefully controlled to achieve the expected frequency shifts. That's also assuming the frequency shift is a linear function of the modulation voltage, which it might not be.

I’m not sure it won’t work in particular with a linear translator. The input signal is typically down converted to a base band IF frequency then up converted to the output frequency. The signal is not demodulated during the process. Remember that digital voice is really transmitted using specially modulated analog RF such that it carry’s digital data. The pulse shape is such that it has a very narrow bandwidth. So long as the translator is linear and the bandwidth of the digital signal fits within its input and output band range it should be repeated just fine. The one area that is difficult as you pointed out is the Doppler shift. Most of advance digital modes use some form of multi level frequency shift keying. For it to work you need very good frequency accuracy. With good orbit parameters and model a computer controlled radio readjusting the frequency on the fly might work. It works well enough for SSB on the birds up there now since as we well know an error of 10’s to 100’s of Hz results in unintelligible signals so there is a chance.

I guess if you really want a challenge try running a digital voice mode through one of the satellites. I remotely remember reading about a Ham that claimed it was accomplished with DMR.

I did at one time. https://www.g0mrf.com/ao-40.htm I had a portable setup for AO-40, 70cm SSB uplink working with an 11 element M Squared Yagi, https://www.m2inc.com/FG4205011 and the down-link was on 2.4GHz with a UEK-3000 down converter to the 2 meter band working with a 24db dish antenna. http://websites.umich.edu/~umarc/files/misc/UEK-3000.pdf https://www.radiolabs.com/wireless/wifi-antennas/directional-wifi-antennas/parabolic-grid-wifi-dish-antenna-24db-2-4-ghz/ The radio I used at the time was a Yaesu FT-847 with an optional after market IRAD RX IF crystal filter for SSB. I made a couple of contacts through it. The down-link signal wasn't that strong. https://www.hamradio.co.uk/userfiles/file/FT-847.pdf https://w6aer.com/ft847-inrad-filter-modifications-upgrade/ Because of some screw up the satellite ended up in a very highly eccentric orbit. At the farthest point the distance was around 40K miles. The delay in the down-link in the head phones was about a 1/2 of a second, very noticeable and hard to adjust to hear one self with a delay. The advantage at that distance is the satellite hardly moved for about 10 to 15 minutes making manual static pointing of the antennas practical and almost no Doppler shift. I lived in a ground floor apartment at the time so I needed to to drag the whole antenna setup outside every time. That was done late at night to attract far less attention. The last thing I wanted were the other tenets calling the local PD thinking I was some kind of spy or terrorist. The van had enough strange looking antennas on it as it was and I got a few people driving circles around it at shopping centers staring at them while giving me weird looks. Oh well. 8-/ I made a few contacts on FM through a low earth orbit satellite, mode U/V, from a mobile using an Icom IC-706MKII I had with some simple vertical antennas on the roof. Those satellites tend to get very busy since they are far easier to work.

Have you asked for permission to use the Troy575 repeater? If not you have nothing to lose. I’ve had some luck running 15 watts and a high gain mobile antenna from Oxford to the north. I’ve also heard a few mobiles almost out to Novi to the west. I’m in Sterling Heights so that puts me about 4 to 5 miles from the repeater. Works pretty well at 1 watt on a portable. TROY 575 Repeater Group: [143] Members: 07/03/2022 1. ADMINISTRATOR: Dave R.: WRAB 719 / K8RDG / Mio / wrab719@gmail.com

OK. It wasn't clear to me which one you where talking about. Yeah, I wonder why it was canceled. 8-))

If you’re referring to WROY767 his license was granted on 12/31/2021 and good to 12/31/2031. He also seems to be located in the middle of an extensive linked digital Ham repeater network too being located in Venice Florida. https://ni4ce.org/nxdn-digital-communications/

People might find this an interesting reference to read. R-HDB-24-1996-PDF-E.pdf

At $3K not exactly cheap and you still need two antennas with feed line and space to mount the separated antennas. So apparently the repeater is really two separated independent FHSS radios that exchange the digital audio using a fast Ethernet link. Since you can’t use cavities to isolate the TX and RX you need the physical separation between the antennas to provide the necessary isolation. Calling it a repeater is sort of stretching the definition a bit. It looks more like two independent network connected radios.

It’s not a question of what I like. More like what fits the application given the limitations. For example with GMRS you only have 22 simplex channels and out of that 7 are limited to just 1/2 watt unless the FCC allows more power for digital, which is possible I guess. That leaves just 15 frequencies, not a big hop set otherwise. I’ve also been looking at some of the testing and research for a “possible” move to digital voice on the VHF marine band. I believe that’s on the docket for the WRC23 conference. Apparently TDMA voice modes like DMR and TETRA are not being recommended. They are leaning to systems using FDMA. One that I saw mentioned was dPMR. While some like DMR, don’t get me wrong I like it too and have been looking at getting a few more radios (NX-1300DU which I don’t have in my collection for example) and I do have a few XPR6550’s. I read some interesting comments about DMR not being a huge favorite of frequency coordinators particularly when 6.25KHz channels are in the area and they need to assign additional ones. The reasons mentioned were some I never considered before. And yes I’m aware of the long thread on digital modes back in 2021. I even made a few posts to that thread myself towards the end. Funny thing is nobody seemed to mention spread spectrum technology that I recall.

That might work for a large site. However if one wanted to install a private repeater for family use it doesn't look practical. Also as far as I know there is no open standard for FHSS radios so any implementation would be proprietary and the manufacture likely wouldn't be all that interested in opening it up or licensing the technology. So further along that line if another manufacture sold FHSS radios they probability they would work with another manufacture is nearly zero. That's why an open public standard or one that is open to licensing is much preferred.

The goal of trunking systems is far different than for a FHSS radio. Trunking systems are used to increase the utilization of very limited spectrum, frequencies, while FHSS radios consume a lot of spectrum while minimizing interference.

That was exactly why I asked the question. I've read some archived posts talking about various digital modes where people are singing about how great they are, except they forget about the practical aspects. So if FHSS radios are so great what if one wanted to expand the range beyond a mile or so they would need a repeater. Oops, not going to happen. Looks like they might not be a great recommendation after all. I just wish people would think a little bit more about the practical ramifications and implementation requirements more. When that's done you just might discover the digital mode you thought was the greatest thing since sliced bread, and better than anything else out there, just isn't a good fit while another mode would be better suited for the application.

There is likely one area you haven't checked. Your typical cigarette lighter plug has a spring loaded center contact pin on the tip. The contact area with the pad inside of the socket is really small. At moderate to high currents this area will get really hot depending on the current draw.

Here is a real question. Who makes a practical and affordable FHSS repeater? I did a search and didn't really find much of anything. If the radios are only usable for short range communications because there is no infrastructure to expand the range sort of takes the shine off the attraction to FHSS radios as a general communication tool.

If the button was defective then nothing you assign to it would work either so I don't think that's your problem. At this point I can't think of any other reason why it won't work from a setup stand point. I do know you have to have at least two channels selected to scan otherwise it doesn't do anything. I would recommend you look through the help file for the options in the SCAN panel and make sure you understand what each option does and if it makes sense for what you want the radio to do.

I would recommend the following setting in the SCAN option panel. Make this setting FIRST. If it's set to anything else the radio will only scan the selected channels in the current group. Using the "MULTI" option any channel in any group can be scanned regardless of the current group the radio is set for. After the above then you need to edit each GROUP to enable scanning the channels in that group as well. You need to do both of the above.

OK. My misunderstanding.

This is what he wrote on a follow up post showing the radio's display. It seems he figured out the tone issue but some how mucked up the display settings. That's what I responded too in my reply. "I somehow got it working, but no idea what setting I changed but now rather than a channel name showing up,like it was, it is just numbers." "Now I have no idea how to get it back into showing the channel name. Is it capable of showing the channel and name and channel number?"

His last post was asking how to get the channel names to display. He said he wasn't sure what he changed to screw it up.

Change this setting.

Analog radios for 220 are around. Since the band is typically only for ITU region 2, North America, most major manufacturers don’t bother making radios for it or including it on multi-band radios. When looking at digital voice the choices are very limited. As you guessed the antennas are an issue too. Most Ham bands are harmonically related. For example 432MHz, 70cm band, is exactly 3 times 144MHz, 2 meter band etc. The 220 band isn’t so making a multi band antenna is really hard to do. Some of the radios ship with 2 antennas, a combo for 70cm/2M and a separate one just for 220 for that reason.

Then it seems you are one of the few lucky ones. When you get the whole thing reassembled do one more scan using the radio the battery replacer is installed on. If nothing is noticed you should be good to go.

Did you mean to say powered up? If it wasn't powered up you wouldn't expect to hear anything.

It’s also a band where you’re unlikely to find much if any digital voice operation. I only know of two Ham grade radios that can do digital voice on 220. One is the now discontinued Kenwood TH-D74A with D-Star and the other is the Anytone D578UV with DMR. There might be others, maybe System Fussion, but I haven’t heard of them if they exist. Both of the above radios are rated at just 5 watts on the band. I think if one wanted to run DMR on 220 then the D578UV is the only game in town, even if it’s a Chinese radio. I think BTECH sells a 220 amp that works for FM and all the usual digital voice modes. It’s not that expensive. https://baofengtech.com/product/amp-220/