We seek to understand and document all radio transmissions, legal and otherwise, as part of the radio listening hobby. We do not encourage any radio operations contrary to regulations. Always consult with the appropriate authorities if you have questions concerning what is permissable in your locale.

Show Posts

This section allows you to view all posts made by this member. Note that you can only see posts made in areas you currently have access to.

Messages - OgreVorbis

Pages: 1 2 [3] 4 5 ... 9
Ever since I was a kid I wanted to be a radio DJ. I built small FM transmitters as a teen starting out with rigging in audio to the internals of another FM radio and using the local oscillator to rebroadcast a few houses down from mine. Grew up and pirated FM with higher power, got up to 10 watts or so on FM and a 40' tower. Covered most of my town. Had friends come over and we'd do shows and had the local Taco Bell guy a mile away call in just to hear his voice echo over the cell phone and his radio.

I got paranoid after a while and part of that was my own doing trying to get the word out and I was always getting high and/or drunk at the time. Had a bad cough syrup habit but that's another story. Anyway.. after learning not only did my friends know about our FM station.. the whole damn town knew which surprised me. Doesn't help it is a 11k population so word gets around, but not in the way I wished.

So I switched up, went to AM because my strength is electronics and having fun with electronics. Got on medium wave and still have it setup for the occasional power switch flip to start broadcasting. I'm saving it for winter though when conditions are best and FCC is stranded.

Thing is the lack of interest now. Radio in general is dying. Any of us who deny that are clinging to memories. I sure know I cling to those FM days in the late 90s to 2008 or so. I had a lot of fun then and we had a ton of listeners. I had a phone patch, aka: cell phone with cord spliced into the mixer, but hey.. it worked!
My point here is the medium itself is dying because in general most broadcasts on AM/FM are talk radio and music, and not good stuff. It's all syndicated garbage, no local calls, no requests.

Us pirates aren't doing so great either in my opinion and I know I will take hate for this but I tune into shortwave on 69xxkHz and it's always the same boring music I can get on FM radio, the DJs don't talk much and some of them resort to computerized voicing.
What happened to broadcasting with actual talk, maybe a friend or co-host? No offense to those who don't, I believe everyone with the ability should get on the air, but the programming has become stale lets face it. We get out our tablet computers or phone to see what song is playing if we don't know just to type up a reception report. Yeah hooray you emitted RF and we could hear it. There are some really good pirates still around and I won't name names, but they can carry a program and often blast a radio. So if you got low power make that programming count or else you just become another log note.

Sorry I don't mean to sound like a dick. I just remember pirates of the 90s and so, there was more effort rather than running a play list. I say this because I realized that is exactly what I was doing with my AM radio station on 1710kHz. Wondering why I didn't get more listeners, then sat back and thought... would I continue listening to this just because it's on the radio? 

I'm just wondering what is the way forward? I seem to be going backward with AM now instead of FM broadcast band pirating simply because it's literally getting to the point where FM radio has killed itself and no one wants to listen to Hotel California one more time without shooting their brains out. At least AM offers more fun, which is so damn backward when you think about it. What has become of all this?

Yes, I see what you mean about all radio being homogenized. Even a lot of pirates play very generic music and don't put much effort into making an interesting show. That's not to say that there aren't some pretty unique and interesting ones out there. I think a lot of them do it mostly to get reports (like ham radio) rather than actually focus on the content. Which isn't a bad thing necessarily if they are concentrating on the technical aspects of the hobby.

Radio has sort of killed itself, but that's kind of a good thing for the pirates. Eventually these bands will become so rare that the FCC won't care as much about policing it. I hope...

I am kind of surprised that there aren't more talk orientated political pirates out there. You would think that a big reason for being a pirate would be to get fringe ideas out there. I wonder why it's mostly music?

General Radio Discussion / Re: Direction finding of a skywave signal
« on: October 29, 2019, 1005 UTC »
They can probably get a bearing on it. Then they just have to get within groundwave to get your location.
I know that the authorities have traced me to about 10 miles of my location purely on skywave  :( Thankfully, where I live they not bothered about me.

It seems that on the lower HF bands, the groundwave doesn't meet the skywave. There is a large ring of no reception surrounding the groundwave. Have you noticed this? This is probably even more significant with horizontal antennas like the inverted V. A good reason to not use a vertical antenna.

General Radio Discussion / Direction finding of a skywave signal
« on: October 29, 2019, 0906 UTC »
With all the shortwave pirates here, I am curious about how easy it is for the FCC to direction find a skywave signal. I would assume it is much harder than for VHF bands. Is it really even practical to do on a vehicle?

... you will need a tuner/SWR analyzer for that kind of power though. An MFJ SWR analyzer should do.
And of course an antenna in your basement is not optimal for this.
Try putting a long wire outside and then ground to a water pipe in the basement.

Here is another option: https://www.ebay.com/itm/20W-HF-PA-20-watts-24v-HF-amplifier-for-HAM-radio-CW-SSB-FM-digital/332643829840
You need an attenuator -20db for it: https://www.ebay.com/itm/Attenuator-SMA-MF-6GHz-Male-to-Female-2W-1-60DB-RF-Coaxial-Attenuator/323827300226

Start a new thread next time. It's not good to resurrect old threads from 2014 even if they are somewhat relevant.

I just found your 2014 forum's topic about your search of an RF amplifier
to make more power out of your Spitfire transmitter.
I'm looking for the exact same type of amplifier for my SSTRAN transmitter.
So far I managed to get more power from it by using around 25 feet of wire
'stapled' to my basement ceiling. Doing so I went from 10% reception to around 60-70%
on my Harman Kardon AM receiver ! The wire placement is very important and picky though..
So what RF amplifier did you find since then ??
Jean-Pierre Desrochers


This guy normally has EXACTLY what your looking for, but it looks like he's out of stock right now. It takes about 0.1 watt and makes about 6-8W.
This is a fully build transmitter that he makes. Maybe you would find it interesting. Keep an eye on his shop, the amps will probably be back. I've seen them disappear briefly before.

The real name is Lesvos Electronics of Greece.

Check this (RF INPUT:0.1-1W)
But it is a bit overkill: https://www.ebay.com/itm/AM-LINEAR-AMPLIFIER-150W-600W-PEP-MF-HF-0-4-3MHz/233237832811
It probably won't drive to full power, but it should still produce a lot of power.

The RF Workbench / C-QUAM stereo on PWM TX
« on: October 29, 2019, 0045 UTC »

Redhat, your mention of c-quam with a PWM transmitter got me interested, so I thought I should make a separate thread about it.

As I understand it, you modulate the PWM as you normally would with left and right channels mixed together. Then for the c-quam, you need a device that will offer a phase modulated TTL square wave and you feed that in where you would normally have your crystal oscillator?

Do such devices exist? Could a regular part 15 100mW c-quam transmitter have this extracted from somewhere in the circuit or do I need to build my own device that produces it?

As a side note: It also got me thinking - what would happen if you got two PWMs and fed each side of the amp separately (assuming push-pull design)? would it make an ISB type stereo?

The RF Workbench / Re: NCP driver sucks
« on: October 24, 2019, 0833 UTC »
That sounds about right!

Looks like you're on your way...

I must have had mine finished for over 2 years now but stuffing the thing in a commercial available box with the modulator and filter + making it unblowupable has been a challenge.

I think building one of anything is relatively easy. However building 25 and making it easy to do has taken me over 2 years!

I reckon I'll sell 2 a year, so really a complete waste of time one might say but I don't mind, keeps me busy!

I really pleased at the progress you've made.

May I ask about your modulation scheme?



Sure. I'm going to use a Greek PWM board. I have it already, but have not tested it yet. It's a spruced up version of this kit (using bigger FETs): https://www.s9plus.com/puwma%20draft4.pdf

So I've done a bit more experimenting. I made it to 92% @ 6.8 MHz with 12V drive.  :)
Something is a little weird though. I need exactly 470pf on only one side of the amp. Like I said before, I think I need to change my balun back to the original wire wrapped one I was using. This new one uses coax and it's a bit strange. Could I somehow be fooling the bird meter by using a cap on one side only? If not, then it's got to be my balun. I'm going to put the old one back in tomorrow and see. The new one was actually 1% less efficient or in the noise.

I should never need more capacitance on one side, right? Each side of the amp is exactly the same, so I am guessing it has to be the balun.

The RF Workbench / Re: NCP driver sucks
« on: October 21, 2019, 1846 UTC »
Eff will suffer at 10V and FETs wont be fully on and dissipate more heat.

Don't know why you can't just whip off the drivers with a hot air gun, bend the pin and reseat or just lift the pin with a scalpel whilst heating with an iron. I'd always breadboard first.

However you should be ok with the design now. Don't use any grease and just use the greasless insulators (orange ones).


My PCB company is so fast that it's not worth the effort. The board arrived yesterday and I finished installing everything and tested it.
The inverted inputs work!!!
The efficiency (87%) is not too good, but I know the reason why and I think I can fix it.
The way I connected my balun, I think is a little unbalanced  :)
I need 270pf on one side and nothing on the other to produce the 87%, so I've got a balance issue. I am going to fix the balun because with the way it connects, the one side is a little longer.
That should help and then I am going to try 12V with some little heatsinks and see if I can get into the nineties.

At 12V 4 of my NCPs draw 430mA (operating at 10V through regulators), but that's along with the crystal oscillator and voltage regulators which get a little warm.

The RF Workbench / Re: NCP driver sucks
« on: October 19, 2019, 0534 UTC »
Just fired up my 'Older' design with 4 SiC FETs (I use GaN now) and Yep, 93% efficient.

382W @ 48V 8A55.

Running a 100W carrier at 24V eff is around 96%.

The whole amp is passively cooled and barely gets warm at carrier, so cool in fact I wonder where the power is coming from!

The whole system is calibrated so I know it accurate to a few %, DC and RF wise.

12V I is around 410mA and that's for 4 NCP's and the AD9850 (which gets a bit warm).

So I rekon around 80/90mA per driver?

The drivers do warm up but I can just keep my finger on them (for a while!)

I run the NCP's at 12V and noticed ONLY a 0.3% increase in eff moving to 15V, so 12V is fine.

So not sure why your having the heat problems.

Your layout isn't that different from mine except that I am trying to use the built-in inverted inputs.
It's too hard and kludgy to try and lift those pins, so I just ordered a new board. Waiting for it to arrive now.

It could be because I put too much thermal paste under the fets and it bulged out and bridged the gate and source. It's not conductive and I've verified that, but it could be a little capacitive. That's my only guess. I'll be careful not to do that when I install the fets on the new board. They do seem to work alright at 10V, so that's what I am going to use. 12V and I can't put my finger on them for more than a second. I may be able to find a type of heatsink like they use on motherboard voltage regulators if I decide to run it at 12V.

The RF Workbench / Re: NCP driver sucks
« on: October 15, 2019, 1444 UTC »
I have used the NCP up to 7.290 in the past. Inverting and non-inverting. What keeps them from frying is a few ohms between the driver and the SiC gate.

I thought that was only for protection if the mosfet blows out, so it reduces the current consumption of the driver with no side effect?

The RF Workbench / Re: NCP driver sucks
« on: October 15, 2019, 1112 UTC »
On one side only..

Ok, does it work??


Well, the non-inverted side already works fine (with less than 12V). After reading the truth table again, I don't see why this wouldn't work. Unfortunately, the only way to find out is to send for the PCBs again. I'm just going to go for it. It's only $35 for 6 of them and it's not something I can hack onto my current board because those pins are grounded, so I can't just connect a wire there; I have to get new PCBs. And I shouldn't need pullups or pulldowns because that pin should always be high.

The RF Workbench / Re: NCP driver sucks
« on: October 15, 2019, 0016 UTC »
Drive the '-' I/P on both sides but pull up the '+' I/P on one side and down on the other side.

Sounds more complicated than necessary. Do I need to do it that way?
Alright the modification has been made. I just connected the non-inverted input to 5V and drive the inverted input only.

The RF Workbench / Re: NCP driver sucks
« on: October 14, 2019, 1548 UTC »
Maybe you have to tie the positive input pins high to get the inverter function to work?


Now that I look at it again, yeah, I think you're right.

The RF Workbench / Re: NCP driver sucks
« on: October 14, 2019, 1456 UTC »
The design I use uses the AD9850 PCB's on Ebay and they O/P opposite phases already so I've no need to invert.

I'll have a look at your 'problem'....


OK, tie the O/P's together, ground the I/P you don't want to use, drive the other.

That should give opposing O/P's.


Right, that's what I did and none of the inverted ones are working. They are always low. I checked with a scope right on the output of them.

If I fix this, maybe it will work  :o Even with only one side of the amp firing, I am getting almost exactly 50% efficiency, so I think if I can make the other side work it should be pretty good.
I found that 10V may actually be enough for the drivers. It doesn't seem to lower the output/efficiency until I go to 9V or less.

I don't know if you checked the image of the board, but here it is. You can see the subtle change on the drivers for each side.

Thanks for the help stretchy.

The RF Workbench / Re: NCP driver sucks
« on: October 14, 2019, 1147 UTC »
Thanks for the replies!

The NCP's are fine to beyond 14MHz driving GaN.

The issues arrive from driving Qg and the SiC's I use, C3M0280090D have a Qg of 9.5nC. (GaNs have Qg of 6nC)

Power required to drive FET is QgxfxV, so 9.5e-9x7e6x12 = 800mW so they get a bit warm but are fine.

Apart from one op blowing the sh*t out of the whole Tx by powering it with A.C. I've never had one blow.

Are you using the same SiC FETs?


Yes, that's the one I'm using.

There must be some small difference about my PCB that's making it not work, but it's just too marginal. 800mW in that SOIC-8 seems like a lot. In my situation they are also hand soldered, so the dissipation through the pins is probably not as good as if I had used solder paste.

If I was going to continue this, it wouldn't be hard to make a GaN version of the board because it would just require swapping the drain and source pins. Then the NCPs would run easily with a lot of headroom.

So then the only problem I would have is getting the inverted inputs on them to work.

Stretchy: Have you used the inverting inputs on these? How do you wire it up? I tried connecting the inverted input to the crystal and grounding the non-inverted input, but the output stays low. I have the two OUTH and OUTL tied together, but I think it's wrong. How should it be connected for inverting? Like I said the datasheet is no help and the truth table doesn't make sense. There is no diagram of how to use the inverted input and clearly it's not just a matter of connecting the input to it.

For the record, all these parts are spec'd to 2 MHz...that is all.  In the early days of using power conversion parts, I quickly found that the DIP package parts smoke driving anything over 1 MHz.  I switched to tabbed devices and all my problems went away...sortof.  It did take a bit of fiddling with different parts until I settled on the '614's.  in most applications, you can use the TO-263 version up to about 9 MHz or so, depending on what you are trying to drive.  My fets are about 1000pf each and the 614's will happily drive them to about that, maybe more with decreased performance and more heat.  I'm not sure if there is much of a performance difference between the 4452's and the '614's but the heatsink tab on the latter is tied internally to VSS, which makes layout and thermal management easier.

Fall is here, and 4 MHz historically has worked much better for me than 6 MHz when the leaves start to fall  8)


Eventually some day when I have more time, it's clear to me that the 614s combined with GaN are probably the best, most durable and fool proof way. I love how the tabs are grounded on the 614s and the transphorm GaN. All fets should be that way.

Pages: 1 2 [3] 4 5 ... 9