Shortwave Capture

[sarma]

Duplicate post by accident --deleted
Sarma

[steveg]

Hi there Sarma
Yes I am still enjoying the SW Capture radio. I find it to be one of the most stable receivers I have ever used, but I still use the dream software for all types of signal reception. You say that you prefer to use a 4.7 instead of 100nf output capacitor. Please confirm is this for the SW capture circuit, and which part number. I shall then try it.
I have found that using the aerial gain instead of the rf gain also reduces the strength of the internally generated false signals that appear after the first mixer. I have also duplicated the bandpass filter after the vfo which further reduces the strength of the internally generated false signals.
The SD radio is very good, but I have also found that the DRM signal is not strong enough for Dream to decode. I prefer to use the SW capture. I have received many dx drm stations, but they are mostly in europe and russia. I do not know what you may be able to hear in your country. The active loop aerial I use is made by Wellbrook. They have a good website. Ref the 45m15b1, have you tried Barend in Holland. They supplied most of my components.(www.barendh.com)
best wishes
steveg

[sarma]

Thanks Steveg,
please see page four of the pdf under link indicated below. this is a normal version with internal transistor osc, - you can see 12KHz output taken out using 4.7uF(C6&R3 in the attached link)

http://www.drmrx.org/mods/AOR_7030_german_high_res3.pdf

the referred component in our sw capture is C53 and the series connected L12(10uH) inductor.

the other schematic i had (- link i will convey) uses a seperate Transistor as external osc, but the NE602 output is like the one above.

Regards
Sarma

PS: referred pdf attached

[jcastano]

Hi all!

I ma new to this forum. I started the SW Rx, but soon i found the first stopper. After fix and solve the broke track and the swap of inductor, the controller and the fron panel PCb are finish. I have to restart the circuit some times to have the LEd working, so i need to include some capacitors and filters to solve the false peak signals. On the other hand the 30 Mhz are working, but on the scope it gives a bad signal (something like a sinusoidal defromed).
and there is no output from DDS CI. some ideas?

The scope is a 200Mhz bandwidth (so no amplifier distorsion).
Regards
JORGE EC3AEL

[kruisb_h]

Hi All,

I just finished my SW capture. This forum was realy helpful for all the gotchas (specifically the keypad and missing MAX7219 wire issue).

I'm trying to attach some pictures

Notice the USB connector on the front. I have designed a replacement module for the controller with a PIC 18F4550 (I didn't like it that the source code was not available due to some copyright or IP issue).

This will be a pull out the controller, drop in the module replacement.

Pity the PIC 18F4550 didn't have an ethernet interface, Microchip have included an integrated ethernet interface on the roadmap for future PIC32 variants, I might develop a new module with the PIC32 with ethernet interface in the future.

The software is not yet complete, but it will allow you to (you guessed it correct) to have full control of the SW Capture from a PC


Cheers,
Henk
UK

[sarma]

Hi Kruisb_h,
Congratulations. The cabinet and mounting plan appears NICE. Lovely to know that you are going to implement PIC based DDS and radio interface.

Thanks for such NICE photographs, I await further developments.

In fact I happened to see the post just now, and liked your approach to it.

Sarma