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Topics - syfr

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16
Equipment / Interesting Chinesium SI4732 Shortwave/Air/FM
« on: April 01, 2021, 2219 UTC »
https://www.amazon.com/Receiver-Airband-Portable-Handheld-Recorder/dp/B08ZDHT7LY/ref=psdc_172653_t2_B08Z8L9ZYZ

Anyone seen any reviews?

It's cheap enough I might take the gamble. After all:

Application: Si4732 radio receiver suitable for outdoor camping, listening to radio music in the kitchen, it is a necessary condition for participating in the parade and family life

17
HF Beacons / Trifecta
« on: March 29, 2021, 1546 UTC »



Nice image of three beacons in the 4096 area, including DW and a couple dashers.  This is via KFS, but DW and one of the dashers are also audible this morning at 1530 UTC on the degen portable, here in the Ca central coast area.

18
HF Beacons / Power output of MX beacons?
« on: March 08, 2021, 2345 UTC »
I suppose this is information that is beyond obscure, but has anyone ever seen a reference that might define the power output of the various MX beacons?

Hard to imagine they'd intentionally run huge power given their stated purpose.


19
SDR - Software Defined Radio / Kiwi recording/postprocessing
« on: January 13, 2021, 1532 UTC »
Does anyone do bulk recordings of Kiwi specific frequencies (or bands)?  Can you record/replay the IQ data or only the audio stream?  How do you post process it to review the data?

Inquiring minds

John

20
HF Beacons / 5150.4
« on: January 13, 2021, 0225 UTC »
Been hearing this one for a while, as I'm scanning for the MX beacons.  About 2 sec on 1 sec off. Copying on my Kiwi, 0220Z.  Listened on your Kiwis Chris, but no joy.




21
HF Beacons / Saturday night trio-- the 4094 joins the party
« on: January 10, 2021, 0104 UTC »



^^^^^^^^^^^^^^^^^^^^^^^^^^
img tags don't seem to work for me, so:

https://imgur.com/a/L7GE7u5


4094 and DW and The Dasher via the KFS Omni

22
HF Beacons / NYrs ditter/Dasher/whooper
« on: January 01, 2021, 0037 UTC »


Via KFS Kiwi...note that fine ditter signal !

23
22 Meter Band HiFER Beacons / wv
« on: December 22, 2020, 1604 UTC »
WV just pounding in here honest S4 CW

24
For Sale / Wanted / Barter / For Sale: Working HR2510-10M CW/SSB/AM
« on: November 01, 2020, 1649 UTC »
I have a HR2510 10M CW/SSB ham rig I was going to use on 10 M beacon applications, but I built a QRPlabs rig for that.

Comes with mobile mount , copies of manual/documentation, etc.

125$ plus actual shipping cost to your location in my bullet proof packaging)

Paypal please

25
HF Beacons / 4095.8 & 6700
« on: September 10, 2020, 2335 UTC »
Making it into the KFS SDR at 2334 Z....

6700 quite strong into same.

Even with marginal prop today!

26
SDR - Software Defined Radio / Chinesium "msi sdr" (Blue dolphin)
« on: July 01, 2020, 1403 UTC »
I got one of these to compare to the RSP1 they're supposedly similar to.  First thing I noticed is that something was rattling inside the blue anodized case.

I took it apart (4 small screws on each end) and the board slides out of its extruded aluminum case.

That's nifty BUT what it means is there's zero electrical  connection from the board to the case.

I soldered a small piece of solder wick to the ground plane, filed off the anodizing from the mating surfaces of the housing, pinched the solder wick between one end plate and the case and tightened everything down tight. Now there's a good ground connection between the board and the case.


As usual, the Chinese ALMOST get things right.... but....

 Now, to see how it works with openwebrx.

27
22 Meter Band HiFER Beacons / WV vy strong 13553.48
« on: June 18, 2020, 2349 UTC »
Chris's Kiwi has great copy on this station right now.  Easy 5-7 9 signal

28
SDR - Software Defined Radio / Multiple virtual audio cables on one PC. Is it possible?
« on: June 06, 2020, 1435 UTC »
While I'm migrating most of my SDR stuff to Pi's, there's times where it's handier to host them on a PC.  My question is, is there a way to create more than one Virtual Audio Cable (the software I'm using to pipe stuff around a PC between SDR's and software) in Windoze?

Thanks in advance for any advice .

29
The RF Workbench / More beacon simplicity (and economy)
« on: May 28, 2020, 1308 UTC »
I've messed with a fair number of small beacon circuits and am interested in your comments on this.

I've been using the Epson programmable oscillators for a while, in ISM band HIFER use. They're super cheap ($4 , programmed to your 4 digit places of accuracy). 

https://www.digikey.com/product-detail/en/epson/SG-8002DC-MPT/SG-8002DC-PHC-ND/275176

I'll have to re-measure my HIFER into a 50 ohm resistor, but IIRC it's about 4mW output.    Programming takes 2 days and it's at your door in a week.  What a bargain for FOUR BUCKS.

Following up on Stretch's post of an old familiar CMOS inverter transmitter, I'm going to try replacing what's hanging off pins  11 and 9  in this schematic:

http://new-ham-radio.blogspot.com/2010/07/is-it-possible-to-create-qrp.html

With one of the Epson oscillators.

Keying will be handled by an ATTiny 85 stuffed with any of the million keyer software packages available for download. I've not programmed a Tiny but have done so with a Arduino and I think it can use the same IDE. I have one of the dev boards to mess with and a programmer of fine Chinesium quality.

Given that power budgets are where it's at for solar powered beacons,  Class E is the way to go.  The epson oscillator has a chip enable so keying it from an ATTINY should be straightforward, and the AT TINY can be put into super efficient sleep modes. 

Anyone see any major problems with this concept?   Digikey has decent shipping ($5) in US and they're fast at programming (2 days).

First application will be a QRSS transmitter for 40M, but if this works, the possibilities are endless, and the frequency flexibility of these things is handy.


30
SDR - Software Defined Radio / The collected wisdom on SWL antenna selection
« on: May 27, 2020, 1621 UTC »
Hi All,

I have an SDR or two I am going to deploy for HF reception.  I hope to link to them via WiFi to avoid a DC connection to my house.  Power will be a DC feed (yes, a dc connection) but via a  run of "fusible link" thin wire , before connecting to a choke and onward to a DC supply.  The whole arrangement is going to be assumed to be somewhat sacrificial as I live in NC, and lightning  is a way of life.  The idea is that my house is not sacrificial.   

I have a tower and a yagi etc, but that stuff is all disconnected during lightning season except when I'm using it.   I do have about an acre of woods back there with a ton of trees that I can hang things from, though I really don't want to erect something super complicated at this point .

Here's the question.  What recommendations do you have on a broadbandish wire antenna ? Let's assume it's not tunable (so broadband is a poor term!) for HF ?    I've never messed with a loop and I do have one of Chris's  multitap impedance transformers available for this , so those are on the radar screen.  If that's a good solution, what design/dimensions would you recommend?    I guess a G5RV is kind of a loop/folded dipole/squashed loop.

I've got a lot of wire if needed.

Your thoughts appreciated. Chris, what works well for you?

I don't want to put my Kiwi out there, but an MSI SDR might be expendable (I want to stick a RTLSDR dongle out there first just do do a proof of concept on the wireless link, etc).    I know their limitations!

Thanks!



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