Electronics, Radio Communications, Amateur radio and other related topics. These videos will be geared toward the technical but also to strive to be easily understood by the non-technical.
Nice video. Well done. Just one correction: you CAN program it through the RS232 Port & using "U-Center" (for u-blox). There are literally 1000's of configurations for the GPS receiver. Including what Satellite Networks the GPSDO are enabled. GPS, Galileo, Glosnos, etc.... Here's a good video of how U-Center works by Tony Albus for this particular GPSDO: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-eAdJSErqZOk.html Skip to "17:42" min to get to u-center. He also has a download URL in his description.
Mine exhibits a lot of harmonic output in the absence of an output LPF, which is needed before putting this unit on the air. The manufacturer also states that it must be protected from any accidental output open circuit or short circuit load and will only work into a maximum SWR of 2.0:1. I have an output load out-of-range detector and shutdown circuit, which I designed and built myself. This circuit of mine will both ground this amplifier's bias line (to zero volts) and inhibit exciter transmit power being applied by disabling PTT when the output load is out-of-range; open, short, or SWR greater than 2.0:1. One diifficulty I had with this amplifier's PCB is there is insufficient clearance between the PC trace for the center tap of the secondary side of the input ferrite RF transformer and an adjacent swath of ground. This can result in an evasive intermitten short to ground on the center tap of the secondary side of the input ferrite RF transformer, which kills the bias to the power FET gates.
I know this video was made a while back, but do you have an actual drawing or some written reference for this. I would love to make one of theses. I am looking to do one for the CM108 card mods, and this is very similar, but different. Love doing this kind of stuff. 73, KN4VA
Building one for usdx 5w HF transceiver. How do you get around the PTT circuit? Jumper? Do you recommend adding low pass filter. Work mostly 20m DX. Thanks. Kk3sc
I have a 16 channel MaxTrac on 45 Mhz . Can you modify mine to 32 channels and program to 6-meters?? What is your contact information and address so I can send it to you? Thanks, Joe (WD8BVL)
That still is an excellent and simple solution. If the availability of 9.6 MHz OCXO's didn't dry up, I would have updated and cleaned up that board and maybe changed it over to surface mount components. Also, that PCB was my first attempt at designing my own PCB's and when I look at it now, I cringe a little bit LOL! it may be ugly, but it works! I still have 5 of them in service at the moment. I'm glad they are working for you and hopefully continue to work for a good long time. Just curious,but how many simulcast sites do you have in your system?
It would shoot the parts count and cost way up. The accuracy and precision this provides is more than enough for radio simulcast. Granted, an OCXO would provide better hold over, but without a GPS signal, the RTCM/Voter Board would stop functioning anyway.
I tried to look at the schematic and I could not find R6. I see it on the PCB and it looks like it balances the input on the gates on the MOSFETs or am I misinterpreting? Will not having this resistor take these parts out of the linear range? Would you explain why you have this concern a little more? Thanks in advance. Thinking of building an amp for an old Tentec QRP rig I have. I probably will build something using an LDMOS and not this one, just trying to understand better.
I bought one of these kits and am having some problems with it. One of the large ferrite cores came with a center hole to small for the bussing to fit in it. Not sure why? And when assembling it I broke a terminal off one of the electrolytic Capacitors. That one was on me. Replacement parts are on the way and we will see how it preforms.
Here is a tip,, when it's happen again use a old telescope antenna. They have multiple sections and diameter. Saw a piece for your ferriet. Thank me later... 😉 Greetings Msc
by now there is a kit on ebay assembled or DIY with up to 200 watts (24 volts /16 amps, 5 watts input). I bought the assembled one and I must admit it is very good soldered an wired
Thanks for the video. I'm hoping to get this to would with my GTX using the correct software. Tried to check out the link and it goes to a page that requires you to install an extension to your browser. Is that right?
I built a Heathkit GW12 CB Base in the 1960's when I was a teenager. I found a working GW12 at the Dayton Hamvention. I replaced all tubes and tuned it according to the manual. I can only get .5 to .75 watts out of it. Will that be enough power to run this little amp? I would think with .5 watt in it should put out 3-5 watts. You mentioned the resistors getting hot, would it help to mount resistors of a higher wattage? I am expecting the kit to arrive July 17 2022.
I hae built this and its still to test. These videos and webpages about someone making it before were very helpful. I had resorted to looking at the pictures of coils how many rounds they needed to wind. Manuals are also quite rare for this, I don't know whether there exists any in Chinese. Still need to acquire load resistor to test this before getting it online. Did cost really nothing, 25 euros including postage.
I haven't got my amp put together yet, but I expect about 15 Watts on 10 meters. Of course, that depends on how much drive power you run, how hot you bias the MOSFET's, and what voltage you power them with. These FET's can be run on 30 to 40 volts. If you run the amp on 13.8 V don't expect even half of what he claimed as output power, and he made no mention of those most important parameters.
Great video! I'm looking for an alternative to the MASTR III's and the Motorola MTR3000 just can't simulcast. I have a couple of 840's i'm now inclined to play with. I still haven't solved the issue with the 9.6 mhz clock in the RTCM making things drift though.
I have solved this issue one of three ways, one is I created a version of the PCGM that takes a 10 MHz reference and can output any freq from 6 MHz to 200 MHz. The other is a PLL board I made using a 9.6 Mhz OCXO that I phase lock to a 10 MHz reference. The last is a device made by Leo Bodnar that is a mini GPS locked programmable freq reference. All three of these option work equally well.
@@Geewhiz811 Nice! How is it in the overlap areas with those modifications? One of us came up with something similar to the PCGM based on a schematic that Jim Dixon sent me. The only problem was that when I attached that I smoked the PIC. Back to the drawing board.
Good evening, I have an XDT-PA100 amplifier. I have a cable for yaesu ft 818. I have a red and black wire on the amplifier. with what color do I connect to the cable cat
Good evening, I have an XDT-PA100 amplifier. I have a cable for yaesu ft 818. I have a red and black wire on the amplifier. with what color do I connect to the cable cat
You don't use the bias to set the power in a push-pull linear amp. The bias is set to reduce crossover distortion. If you set the bias too low, crossover distortion will create intermodulation products. If you want to reduce power, the only way to do it is by reducing drive from the exciter. either use an attenuator or reduce your mic gain.
Or reduce the amp supply voltage. These IRF520's weren't designed as 12 V devices. They are typically run at 24, 28, or sometimes even into the 40 Volt range. Those selling these amps don't make a big deal out of that fact. Most people are having trouble even breaking 40 Watts on 10 meters with these amps unless they crank up the voltage. I'm guessing the ham in this video was running 28 volts or more.
Excellent ! following your tutorial I got it to work first time using a 3Ghz dual core PC running windows 10 Professional. Many thanks for sharing this info and creating the video.
Serial1=directserial realport :com 1 Will assign a port as long as the device is using com1 and the device is turned on and connected to computer.now I am using com 1 as an example.if your device manager said com 2 then serial would be com 2
With dosbox you have to assign a port otherwise it won't work.your application has assigned port yes but dosbox needs to see the port otherwise it will not work
I have the Motorola radius sm50 and I need to change the pl tone.its a gmrs repeater.your a life saver man I looked all over for why the #7 opcode error wrax810 Kn4gtu
sir, what did you do in order for the radio will be read by the software I already adjust the cycle to 191 , whats the power cycle radio means? need your help sir
