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HomeBrew / CraneFly LPAM Transmitter

« on: March 29, 2025, 07:35:19 am »

Below is a now obsolete PCB design for a simple AM Medium Wave Transmitter, ideally design to work at the upper region of MW in the LPAM section of the band. Below attached includes all the PCB design files, EasyEDA project and Manual. Enjoy

Download

CraneFly-LPAM-Transmitter.zip (1146.45 kB - downloaded 7 times.)

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DX Signal Reports & Range Testing / MDR 1575KHz LPAM MW Pirate

« on: March 21, 2025, 05:30:13 am »

Been listening to Maxx Dance Radio on 1575KHz a lot and their signal is doing very well in some areas around Kent. The audio quality isn't bad either. It's surprising how well an AM signal (even with low power) can propagate.

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CB Radio Discussion Board / Re: Magnum S9 Backlight Fault

« on: August 30, 2024, 10:31:52 am »

magnum_s9_echo_sch.pdf (104.08 kB - downloaded 19 times.)

magnum_s980_control_sch.pdf (586.72 kB - downloaded 20 times.)

magnum_s9_sch.pdf (192.76 kB - downloaded 19 times.)

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CB Radio Discussion Board / Magnum S9 Backlight Fault

« on: August 30, 2024, 10:29:58 am »

I'm currently trying to fault find an issue with a Magnum S9 backlight. Its a very intermitant fault, sometime it will work fine all the time its on until a power cycle, and other times it will not work from cold; sometime just a small flash from the meter backlight will be the only indication that it wants to work.

My suspicion is it has something to do with the dimmer circuit which works accross all backlights for frequency counter, signal meter and channel number display.

I have all the schematics, which I'll post here.

Has anyone else has this issue, and being able to isolate the nature of the fault?

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Technical Corner / Re: nrg 40 amp

« on: July 05, 2024, 07:50:38 am »

I'd probably recommend checking the condition of the yellow trimmer caps, even better would be to replace them if they have been subjected to many turns. Also they seem to attract dust and dirty easily which can be dragged inside and damage the thin Polymer film separating the plates and cause a short.

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Linear Amplifiers / Re: BLF245 30W Broadcast Amplifier

« on: June 16, 2024, 10:49:49 am »

Here's the coax transformer cutting lengths for the above board. The total length is the most critical part, other lengths have room for discrepancy.

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Linear Amplifiers / BLF245 30W Broadcast Amplifier

« on: June 16, 2024, 10:09:54 am »

Hi everyone, heres a FM Broadcast amplifier board designed a few years ago now. Its now a discountinued project, so free for everyone to download a use. (see gerber download under image).

All components are marked on the PCB. the LPF is the same as the NRG Pro boards or recent RB LPF in the Technical section on this forum http://www.radiobuilders.co.uk/technical-corner/500w-lpf/

Z30-MK1.rar (26.13 kB - downloaded 56 times.)

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Technical Corner / 500W LPF

« on: June 15, 2024, 09:23:48 pm »

Been busy working the RadioBuilders own version of a 500W FM Broadcast LPF.

Here's a sneak preview of the PCB

More details about this to follow.

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WebSDR's / Re: Hack Green

« on: June 11, 2024, 07:31:25 am »

Anyone know whats happened to Hackgreen SDR. The waterfull has been empty for days, almost like they've lost all their antennas?

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UK Pirate Radio / Re: Playback UK

« on: June 11, 2024, 07:22:07 am »

Sadly nothing heard over my neck of the woods. But Ill keep checking while out and about in the car. Ordered myself a new Tecsun so I give that a try at the weekend.

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HomeBrew / AM Valve Transmitter.

« on: June 07, 2024, 08:51:32 am »

Video of an AM valve transmitter, which has been modified regarding its modulation technique. The video talks about the change from screengrid / clamp tube modulation to series cathode modulation.

Since the video its finally been upgraded to "Heising" modulation, which is very similar in some regards to conventional technique of plate & screen modulation.

https://www.youtube.com/watch?v=I2uganmvI_U

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