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Messages - jFarley

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Equipment / Re: What's all this regenerative loop stuff?
« on: July 16, 2018, 1344 UTC »
A few comments about how the loop Q is controlled...


The above image is a cap of the main form of the app which controls the loop and rotator.  This app has a number of tab pages to organize common tasks, and the RNA tab page is currently displayed below a collapsible pane.  This pane can be collapsed to display the current loop resonant frequency and rotator bearing only, or can be expanded to expose some controls to directly manipulate the resonant frequency and loop Q.  The control with the black background is the Q control and its functionality somewhat resembles a scroll bar.  Clicking anywhere within the bar will send a value (  0 to 255 ) to adjust the loop Q.  This control will also respond to mouse wheel events.  At any level, the current value is displayed in the text box to the right of the Q control.  The vertical yellow bar represents the value above which there is actually a regenerative state in the loop.

The bottom part of the screen displays the current RNA database in a ListView control.  This is an owner drawn control, and colors are used to add extra info to enhance the DXperience.  In this scenario, domestic NDBs are rendered with a white background, Canadians with a red BG, and Foreign with a green BG.  The selected item is rendered with a blue BG. Double clicking on any item in the database will tune the loop to that frequency,  and spin the rotator to the proper bearing.  Note that in the info panel that the bearing for the currently selected NDB is ~270 degrees relative to Chicago, whereas the rotator has been spun to 88 degrees.  This app can use "Smart Rotation" and employs the fact that the loop response pattern is a symetrical Figure 8 pattern.  This minimizes the amount of work (and rotation delay) required to get to the assumed proper azimuth.

Equipment / Re: What's all this regenerative loop stuff?
« on: July 16, 2018, 1236 UTC »
Doing some testing with the loop deployed outdoors.  I grabbed a couple of screen shots which exhibit how the loop Q can be modified remotely to enhance reception characteristics.  The first shows the loop Q with very little regeneration, and this is more or less the native Q of the antenna at this particular frequency.


The 2nd image represents a moderate amount of Q, and is the Q with which I would most likely find most useful.


The 3rd image represents a rather extreme Q level.  Whether of not this is useful remains to be seen when things quiet down and propagation returns on the LW band.


I have added a a wideband noise genny to the loop head, and all 3 images were capped with the noise genny enabled.  The response peaking is clearly seen in the FFT panel, as well as a brightening of the response in the waterfall.

Early indications seem to suggest that the regen loop can usually be adjusted to give greater sensitivity than the amplified whip which is being used for comparison.  This whip has been the workhorse for me as I have used it extensively for SDR recordings and has produced NDB logs from 30 countries in the past 2 seasons.


Longwave Loggings / Re: Michigan NDB logs
« on: July 15, 2018, 1913 UTC »
I acquired these MI logs while antenna testing last week

2018-07-06  1439  254.0  MB   Manistee, MI, USA  319 Km
2018-07-06  1442  257.0  MB   Saginaw, MI, USA  367 Km
2018-07-06  2212  263.0  GR   Grand Rapids, MI, USA  253 Km
2018-07-06  1558  344.0  ES    Escanaba, MI, USA  446 Km

Sat on the rx last night with no luck.  Left the recorder going, but only a trace of carrier around 6876.2.

Quoting Lex: "Dadgum Swiss cheese ionosphere."

Gotta be some major hardware fail somewhere.

Ran an SDR recording, but JBA for the most part.   :(

Happy 4oJ Poet!

Longwave Loggings / Why we don't DX LW NDBs in the summer
« on: June 30, 2018, 1423 UTC »
Logs from Downers Grove, Illinois acquired during a Coordinated Listening Event covering 335 - 349.9 kHz over the period 22Jun to 25Jun18.

2018-06-22  2355  335.0  LUK  Cincinnati, OH, USA  426 Km
2018-06-23  0241  335.0  YLD  Chapleau, ON, CAN  763 Km
2018-06-23  0703  336.0  BV    Champlain, QC, CAN  1446 Km
2018-06-23  0707  336.0  MA   Cadillac, MI, USA  341 Km
2018-06-22  1703  338.0  LM    St Louis, MO, USA  388 Km
2018-06-22  1704  338.0  UMP  Indianapolis, IN, USA  265 Km
2018-06-23  0713  338.0  YPX   Puvirnituq, QC, CAN  2165 Km
2018-06-23  0657  338.0  ZEM  Eastmain, QC, CAN  1367 Km
2018-06-23  0239  340.0  YY     Mont Joli, QC, CAN  1718 Km
2018-06-22  1705  341.0  DB    Dubuque, IA, USA  222 Km
2018-06-22  1705  341.0  SB    South Bend, IN, USA  153 Km
2018-06-23  0659  341.0  YYU   Kapuskasing, ON, CAN  958 Km
2018-06-23  0717  342.0  PFT   Pinecreek, MN, USA  1012 Km
2018-06-23  0721  344.0  BKU   Baker, MT, USA  1394 Km
2018-06-23  0711  344.0  JA     Jacksonville, FL, USA  1376 Km
2018-06-22  1706  344.0  UNU  Juneau, WI, USA  193 Km
2018-06-23  0725  344.0  YGV    Havre St Pierre, QC, CAN  2099 Km
2018-06-23  0650  346.0  YXL    Sioux Lookout, ON, CAN  974 Km

NDBs this report 18  New NDBs 0 (out of the 102 NDBs logged in this freq span this last season)

Longwave Loggings / Re: Take Off to the Great White North
« on: June 15, 2018, 1539 UTC »
Yes; YPL is correct, and is also on 382 kHz.  7B has an offset of ~1015 Hz, while YPL (the dominant Canadian on this freq) has offsets of approx +/- 400 Hz.

The best most up to date NDB listing can be found at: https://www.classaxe.com/dx/ndb/rna/signal_list

Here there are very good search capabilities to help you ID what you hear, and this is an invaluable resource for the NDB DXer.

If you are interested in being a part of the global NDB community, I suggest subscribing to the NDB list group, which can be found at: https://groups.io/g/ndblist


SDR Recording and a very late log due to being in/out of town.

I could generally see the carrier throughout the entire show, with trace audio being the norm.  Signal peaked up to about an S4 with nice audio around 0110 during "Hungry Like the Wolf", but it subsided back to JBA after a short time.

Thanks Poet!

Best of luck, Looking-Glass. Just twiddling thumbs amid very high summer storm noise here.

Longwave Loggings / Re: Take Off to the Great White North
« on: May 21, 2018, 1812 UTC »
MM is a nice log for this time of year, pv!

Equipment / Re: LW 150-500KHz Loop, need help...
« on: April 28, 2018, 1508 UTC »
A couple of questions.

1) Is the tuning control a SINGLE turn pot or a MULTIPLE turn pot?

2) How sharply does the loop tune?  Is the tuning extremely sharp (as it should be for a loop of this size) or is it relatively broad?

3) Does the tuning extend beyond the 150-500 kHz range?

Will be thinking about this thru the day.

Equipment / Re: What's all this regenerative loop stuff?
« on: April 20, 2018, 1750 UTC »
I'm sure it's spewing all kinds of junk when it oscillates!

Equipment / Re: What's all this regenerative loop stuff?
« on: April 20, 2018, 1523 UTC »
This is working out better than anticipated, and I am shocked how well the regen loop seems to behave.  I really expected the worst, that being an unstable hard to control beast.  Not so, apparently.  I am also happy to have most of this work done by January 110th, leaving a lot of time for summer testing.

So far, testing has been done in the noisy confines of my basement, but reception of a couple of NDB locals and the Mequon DGPS has been very promising. 

I have been thinking about other uses.  The resonant loop I use for SW tends to have a Q of around 270 in the funny band.  A couple of years ago I built a higher Q version from copper tubing and a small gap silver plated cap which was giving me a Q of around 600: a BW of around 11 kHz.  Not enough to split close stations, but a very good effective height.  I had planned to try regen on that guy but never got around to it.  Now I am wondering if regeneration would work on the loop I use currently.


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