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 ... 8
1
The RF Workbench / Re: Question about stretchy 350W SiC deck
« on: December 02, 2019, 0833 UTC »
OK, I'll send a PM...

I see, so the match is a lot like this, but with only one core for the transformer:



Interesting they say to omit the L for 40m.

Wonder if it would work at all if you just omit both and just use a 4:1 transformer. Probably not as well, but I'm kinda curious. I will try on mine and see what happens.

I ordered a T200A-2 core for my design. I'll try the match as you suggested and if I still have trouble, then I will order yours.

2
The RF Workbench / Question about stretchy 350W SiC deck
« on: December 02, 2019, 0203 UTC »
Hey stretchy,

I am back at the shortwave transmitter again. I've had it working great below 4 MHz, but now I am back to trying to make it work higher again. I thought I had it at 87% efficiency, but I looked on a spectrum analyzer and it's terrible. When I run it next to the filter, then it's great, but only 76% efficiency @ 6.8 MHz. I am almost 100% sure it has to do with my broadband output match.

Anyway, I'm thinking about buying your SiC RF deck. The 350W one with 4 fets I believe. How much would that cost?

I know you use those T200-2s. What else do you have to match the output beside the transformer?
Yours is not wideband, right? you have to tune it to the band?

3
I don't understand the fixation on using higher frequencies. Just use more power and bandwidth instead. The cost will be lower also because then they won't have to install a base station every couple of feet (I'm exaggerating, but you see the point.) and can use existing infrastructure. Using 400-800 MHz seems the smartest to me because the antenna is about the size of the phone itself and a relatively efficient antenna can be made, but with these crazy high frequencies, it's not going to go very far at all. If they just use the best QAM with wide bandwidth and high compression, they should be able to make it work on the existing frequencies. The government probably regulates the bandwidth on those frequencies though, which could be the reason. Stupid government.

I don't know about toxicity, but I would think it is still below ionizing radiation.

5G could be a good opportunity for replacing the government with blockchain technologies. You need every device to have a copy of the blockchain for security purposes and with the speed of 5G, it could likely be possible. Blockchain is basically like virtual DNA - where each item contains the whole. The government will obviously hate this idea though, but it really needs to happen. All of the government agencies could be paid automatically and directly through the blockchain and eliminate the money getting into the hands of corrupt bureaucrats.

4
Veganism is a cult plain and simple.
My hypothesis is that due to lack of religion in modern society, we have these groups such as SJW and Vegans that treat arbitrary things as their religion. Most vegans don't base their thoughts on facts, but instead on blind belief.

5

Why would you use a linear amplifier for FM service?  LOTS of wasted power.

+-RH

Don't you have to use a linear for VHF band? Confused  :o

I could see what you mean about shortwave though. Using a linear on shortwave is a waste, but on FM...

Maybe I don't know enough about the other classes of amplifiers out there for FM band.

6
There is no mention of this amplifier being used for linear service, certainly not at 70% efficiency.  Tread carefully.

+-RH

Interesting you guys just mentioned this device as I just found out about it myself and I was researching it a couple days ago.

I can be used for linear amplifiers. PCS has done it for FM broadcast band: https://www.pcs-electronics.com/650w-pallet-amplifier-p-3016.html

It's a really good deal for something that can work on the VHF band.

7
The RF Workbench / Re: Pirate Radio antennas
« on: October 30, 2019, 0155 UTC »
The subject of Pirate radio wattage seemed to be an interesting topic. My next question is. What type of antennas are the 'Typical' Pirate stations using. Dipole, Extended Double Zepp, Verticals, Beverage type?

I tend to think inverted V because it's easiest to put up.

8
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?

9
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.

10
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?

11
... 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.

12
Hi,
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 ??
Thanks.
Jean-Pierre Desrochers
Canada

https://www.ebay.com/itm/AM-MW-RADIO-BAND-DIGITAL-LCD-DDS-TRANSMITTER-40-WATT-PEP/323960968980

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.

13
The RF Workbench / C-QUAM stereo on PWM TX
« on: October 29, 2019, 0045 UTC »
Hi,

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?

14
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?

Regards.

Stretchy.

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.

15
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).

Str.

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.

Pages: [1] 2 3 ... 8