Topics

16

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)

17

Equipment / What's all this regenerative loop stuff?

« on: April 20, 2018, 1311 UTC »

I have just verified the operation of a resonant NDB loop which uses positive feedback to enhance the Q which can be attained with commonly available real world components, namely, tuning diodes and Litz-wound ferrite rods.  A working prototype is up and running in the basement here and is showing great promise.

I have re-tooled my ferrite loop so that it is now tuned remotely by a pair of back to back NTE618 tuning diodes (4 diodes total) via a control signal of 0 - 15 VDC.  These diodes resonate a wound ferrite rod (160 turns of Litz) over the NDB band.  The loop output is amplified by a balanced JFET differential amp.  Tuning diodes work great with one caveat: they have a Q which increases with frequency, and vicey-versey.  At the top end of the band (around 400 kHz) they have enough Q to produce a reasonable but not great loaded Q of around 180.  I would really like this to be higher; Q = 250 would be acceptable .  At the low end of the band (around 200 kHz) the loaded Q is only around 90, and the loop, well, the loop sucks.  There is just too much loss due to series resistance in the loop tank, and this needs to be reduced for the loop to perform as desired.  One could use lower loss components in the tank, but this is not practical.  Instead, one can trick the loop into believing that it has lower losses.  If one replaces some of the energy burned up in the lossy tuning diodes and ferrite rod with some energy derived from the loop amp output, then the loop Q should increase.  The loop now becomes a regenerative loop which employs positive feedback for Q augmentation.

The best way to see this is through an understanding of what Q represents.  We have all probably seen that the Q of a resonant loop is the ratio of the loop's resonant frequency to the width of the response curve between its -3 dB points.  As the Q is increased, the loop tunes more sharply, and its -3 dB points move in towards the center frequency.  This is really a result of Q and is not a formal definition of Q.  In electrical engineering, the Q of an LC circuit is defined as the ratio of the energy stored in the L and the C per cycle to the energy dissipated in losses per cycles.   If one can replace some or all of the losses dissipated as heat, then the loop Q must increase.   As one adds controlled positive feedback to the LC tank, one is in effect adding negative resistance to the loss elements in the LC tank.

In practice, I take the output of the loop amp and split it using a toroidal splitter.  One port goes to the coax back to the SDR.  The other port is attenuated in a 75 ohm 20 dB attenuator and passed to a variable attenuator comprised of a PIN diode and load resistor.  This voltage is then applied to a one turn tickler winding on the ferrite rod.  The biasing of the PIN diode is set up so that a 0.7 - 5V control signal will cause a current of 0 to 150 uA to flow through the PIN diode, thus changing its effective AC series resistance.

I have observed 3 regions of operation.  Below a PIN diode current of 1 uA, the loop behaves like the underlying loop without regeneration, and has a generally depressed Q due to the Q of the NTE618 diodes.  If the PIN diode current is increased to a value of typically 100 uA, the loop breaks into oscillation (as it should) and the SDR waterfall goes bat-guano crazy.  Between these 2 points, one can observe the loop Q increasing smoothly above the default level with increasing PIN diode current.  The response in the spectrum pane of the SDR begins to peak higher, and the response skirts narrow.  The object viewed near the resonant peak (carrier or offset) in the waterfall begins to brighten with increasing PIN diode current.  I can typically see an increase of up to 20 dBm in this middle region with increasing PIN diode current before it breaks into oscillation.

The regeneration process seems to be well behaved and stable as the Q operating point is varied, and this bodes well for the future. I am not anticipating running the loop at insanely high Qs such as 10000; I simply would like to enhance the Q of a deficient loop to around 250 which experience has shown is about what is required to make the loop competitive with the amplified whip which I also employ.

Interesting sidebar: if the sense of the tickler winding is reversed - negative feedback - then the regeneration will produce increasing attenuation of received signals as the PIN diode current is increased.

What I now have is a resonant NDB loop with software programmable (and knobless) control of:
    - The loop azimuthal position, with an accuracy of better than 1 degree.
    - The loop resonant frequency with a resolution of typically 100 Hz.
    - The loop Q and thus its Effective Height.

Further details will be posted after it is sited outdoors and fully shaken down.

18

Longwave Loggings / Spring NDB Logs

« on: March 14, 2018, 1740 UTC »

I begrudgingly accept the fact the the NDB season is just about over.

2018-03-14  1153  332.0  VT  Buffalo Narrows, SK, CAN  2152 Km

NDBs this report 1  New NDBs 0

19

Longwave Loggings / Winter NDB Logs

« on: November 11, 2017, 1615 UTC »

All the leaves are brown, and the sky is gray, so time to change threads.

Recent logs from Downers Grove, Illinois

2017-11-09  1131  212.0  LIU  Littlefield, TX, USA  1529 Km
2017-11-09  1126  221.0  HYE  Fort Rucker (Ozark), AL, USA  1179 Km
2017-11-11  0211  227.0  AB   Albany, GA, USA  1198 Km
2017-11-09  0154  233.0  AG   Augusta, GA, USA  1087 Km
2017-11-11  0526  240.0  MJL  Mejillones (Antofagasta), , CHL  7446 Km    New
2017-11-09  0202  245.0  LUA  Luray, VA, USA  883 Km
2017-11-11  0130  269.0  GN   Gainesville, FL, USA  1444 Km
2017-11-10  0231  315.0  IMPEX  UNID, , XUN   New  poss SAC testing, +/- 400 offsets
2017-11-10  0038  335.0  CK   Clarksville, TN, USA  587 Km
2017-11-10  0025  341.0  OW   Owensboro, KY, USA  466 Km

NDBs this report 10  New NDBs 2

20

Longwave Loggings / Fall NDB Logs

« on: August 30, 2017, 1538 UTC »

Logs from Downers Grove, Illinois submitted for a recent Coordinated Listening Event which was looking for logs from your home state and DX logs greater than 2000 kM.  A surprise was the re-activation of ZSJ 281 in BAH which returned after a 10 year hiatus.

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HOME
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2017-08-25  1830  218.0  AL    Alton (St Louis MO), IL, USA  363 Km
2017-08-25  1830  240.0  CJ    Springfield, IL, USA  256 Km
2017-08-25  1831  251.0  JZY   Macomb, IL, USA  252 Km
2017-08-25  1831  254.0  BOZ  Sterling / Rock Falls, IL, USA  145 Km
2017-08-25  1831  257.0  FWC  Fairfield, IL, USA  377 Km
2017-08-25  1831  263.0  CVM  Alton, IL, USA  362 Km
2017-08-25  1832  272.0  IK     Kankakee, IL, USA  85 Km
2017-08-25  1832  272.0  OLY  Olney-Noble, IL, USA  339 Km
2017-08-25  1832  275.0  DE    Decatur, IL, USA  236 Km
2017-08-25  1832  275.0  RF    Rockford, IL, USA  97 Km
2017-08-25  1832  293.0  UI    Quincy, IL, USA  344 Km
2017-08-25  1832  329.0  AAA  Lincoln, IL, USA  213 Km
2017-08-25  1833  332.0  DN   Danville, IL, USA  172 Km
2017-08-25  1834  350.0  CP   Cahokia / St Louis, IL, USA  400 Km
2017-08-25  1834  356.0  PI     Peoria, IL, USA  186 Km
2017-08-25  1834  365.0  SYZ  Shelbyville, IL, USA  274 Km
2017-08-25  1835  375.0  LQ   Springfield, IL, USA  248 Km
2017-08-25  1835  379.0  UG   Waukegan (Chicago), IL, USA  82 Km
2017-08-25  1937  382.0  MW   Marion, IL, USA  443 Km
2017-08-25  1836  382.0  SP   Springfield, IL, USA  267 Km
2017-08-25  1836  385.0  JD    Belleville, IL, USA  393 Km
2017-08-25  1836  391.0  PLX  Robinson, IL, USA  308 Km
2017-08-26  0206  397.0  CIR  Cairo, IL, USA  534 Km
2017-08-25  1837  400.0  SLO  Salem, IL, USA  356 Km
2017-08-25  1837  407.0  CM   Champaign / Urbana, IL, USA  200 Km

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DX
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2017-08-29  1046  266.0  XD    Edmonton, AB, CAN  2303 Km
2017-08-26  0732  281.0  ZSJ   San Salvador (San Salvador Island), , BAH  2334 Km    New
2017-08-28  1041  290.0  YYF   Penticton, BC, CAN  2583 Km
2017-08-26  1007  299.0  TV    Turner Valley, AB, CAN  2245 Km
2017-08-26  0621  309.0  GPI  Guapi, , CLM  4481 Km
2017-08-29  1001  311.0  9Y    Pincher Creek, AB, CAN  2180 Km
2017-08-26  1011  320.0  YQF  Red Deer, AB, CAN  2260 Km
2017-08-26  0957  329.0  YEK  Arviat, NU, CAN  2190 Km
2017-08-29  0402  332.0  FIS   Key West, FL, USA  2001 Km
2017-08-29  1051  332.0  YTE  Cape Dorset, NU, CAN  2607 Km
2017-08-29  0904  338.0  YPX  Puvirnituq, QC, CAN  2165 Km
2017-08-28  1046  344.0  YC   Calgary, AB, CAN  2221 Km
2017-08-26  0619  344.0  YGV  Havre St Pierre, QC, CAN  2099 Km
2017-08-26  0622  350.0  DF    Deer Lake, NL, CAN  2506 Km
2017-08-26  1001  350.0  NY    Enderby, BC, CAN  2556 Km
2017-08-29  0602  350.0  RB    Resolute Bay, NU, CAN  3686 Km
2017-08-29  1006  359.0  YQZ  Quesnel, BC, CAN  2844 Km
2017-08-26  0229  360.0  PN    Port-Menier / Ile Anticosti, QC, CAN  2034 Km
2017-08-29  0951  362.0  YZS  Coral Harbour, NU, CAN  2509 Km
2017-08-29  1051  368.0  SX    Skookum (Cranbrook), BC, CAN  2319 Km
2017-08-28  0937  368.0  ZP    Sandspit, BC, CAN  3465 Km
2017-08-26  0811  369.0  ZDX  Coolidge Saint Johns, , ATG  3710 Km
2017-08-29  0812  378.0  UX    Hall Beach, NU, CAN  3032 Km
2017-08-26  0619  385.0  TKL  Santa Elena Y Flores (Peten), , GTM  2775 Km
2017-08-26  0954  385.0  WL   Williams Lake, BC, CAN  2792 Km
2017-08-28  0249  390.0  JT     Stephenville, NL, CAN  2401 Km
2017-08-26  0158  391.0  DDP  San Juan / Dorado / Luiz Munoz Marin Intl, PR, PTR  3308 Km
2017-08-26  1005  400.0  QQ   Comox, BC, CAN  2969 Km
2017-08-26  1007  406.0  YLJ   Meadow Lake, SK, CAN  2049 Km
2017-08-26  0158  415.0  CBC  West End (Cayman Brac), , CYM  2576 Km

NDBs this report 55  New NDBs 1

21

Longwave Loggings / Summer NDB Logs

« on: July 31, 2017, 2352 UTC »

Logs from Downers Grove, Illinois acquired during a recent Coordinated Listening Event.


2017-07-29  0452  370.0  YBV    Berens River, MB, CAN  1359 Km
2017-07-28  1803  371.0  AZ     Austn' Vicksburg, MI, USA  211 Km
2017-07-29  0500  371.0  FQW  Walter Hill' Murfreesboro, TN, USA  661 Km
2017-07-29  0446  371.0  GW    Jarpik Kuujjuarapik, QC, CAN  1678 Km
2017-07-28  1803  371.0  RYV    Rock River' Watertown, WI, USA  167 Km
2017-07-31  0551  372.0  UQN   Onyun' Vidalia, GA, USA  1178 Km
2017-07-29  0501  373.0  2Q     Mont-Laurier, QC, CAN  1138 Km
2017-07-29  0505  373.0  YXK    Rimouski, QC, CAN  1698 Km
2017-07-30  0323  374.0  EE     Tamie' Alexandria, MN, USA  736 Km
2017-07-29  0120  375.0  7B     St Thomas, ON, CAN  581 Km
2017-07-28  1804  375.0  LQ     Licol' Springfield, IL, USA  248 Km
2017-07-29  0515  375.0  OGM  Ontonagon, MI, USA  576 Km
2017-07-30  0522  375.0  SPH   Springhill, LA, USA  1090 Km
2017-07-29  0521  376.0  BHC   Baxley, GA, USA  1226 Km
2017-07-28  1843  376.0  LC     Pickl' Columbus, OH, USA  483 Km
2017-07-29  0448  376.0  YAG    Fort Frances, ON, CAN  882 Km
2017-07-31  0501  377.0  EHA    Elkhart, KS, USA  1301 Km
2017-07-29  0511  377.0  YRR    Greely (Ottawa), ON, CAN  1081 Km
2017-07-29  0141  378.0  RJ      Roberval, QC, CAN  1445 Km
2017-07-29  0453  379.0  BRA   Broad River' Asheville, NC, USA  871 Km
2017-07-29  1002  379.0  DL     Pykla' Duluth, MN, USA  663 Km
2017-07-30  0507  379.0  LRR    Allen Parish' Oakdale, LA, USA  1307 Km
2017-07-29  0159  379.0  MDE   Madeira' Cincinnati, OH, USA  420 Km
2017-07-28  1921  379.0  OW    Tonna' Owatonna, MN, USA  487 Km
2017-07-28  1805  379.0  UG     Wauke' Waukegan (Chicago), IL, USA  82 Km
2017-07-31  0541  380.0  GC     Deryk' Gillette, WY, USA  1449 Km
2017-07-31  0542  380.0  OEL   Oakley, KS, USA  1119 Km
2017-07-31  0547  381.0  MNI   Manning, SC, USA  1140 Km
2017-07-28  1805  381.5  SJX    St James' Beaver Island, MI, USA  480 Km
2017-07-30  0354  382.0  7P     Iroquois Falls, ON, CAN  964 Km
2017-07-28  1805  382.0  IRS    Sturgis, MI, USA  215 Km
2017-07-29  0451  382.0  MW    Jonny' Marion, IL, USA  443 Km
2017-07-30  0316  382.0  XU     London, ON, CAN  581 Km
2017-07-29  0449  382.0  YPL    Pickle Lake, ON, CAN  1089 Km
2017-07-30  0337  383.0  CNP   Chappell, NE, USA  1205 Km

NDBs this report 35  New NDBs 0

22

HF Beacons / M Beacon 13528.4 1758 UTC 5Jul17

« on: July 05, 2017, 2010 UTC »

Popped up to very solid level for a cupla minutes

23

Longwave Loggings / Spring 2017 NDB Logs

« on: April 25, 2017, 1535 UTC »

Logs acquired during a Coordinated Listening Event this past weekend.  Moderate to high storm noise and very sticky props made this an extremely challenging event.  A very poor showing from our friends to the North.

2017-04-23  0641  335.0  AWS  Columbus, GA, USA  1086 Km
2017-04-22  0532  335.0  BK     Brookings, SD, USA  780 Km
2017-04-22  0421  335.0  BV     Batesville, AR, USA  751 Km
2017-04-21  1843  335.0  LUK   Cincinnati, OH, USA  426 Km
2017-04-24  0802  335.0  MK     Marion, VA, USA  797 Km
2017-04-22  0254  335.0  YLD   Chapleau, ON, CAN  763 Km
2017-04-22  0216  335.0  ZKF    Kitchener (Wellington), ON, CAN  663 Km
2017-04-22  0636  336.0  BV     Champlain, QC, CAN  1446 Km
2017-04-24  0753  336.0  LF     La Salle, MB, CAN  1132 Km
2017-04-22  0351  336.0  MA    Cadillac, MI, USA  341 Km
2017-04-22  1010  337.0  FF     Fergus Falls, MN, USA  810 Km
2017-04-24  0616  338.0  CYR   Cairo, GA, USA  1260 Km
2017-04-22  0224  338.0  DE     Detroit, MI, USA  414 Km
2017-04-22  1031  338.0  HR     Harlingen, TX, USA  1932 Km
2017-04-21  1845  338.0  LM     St Louis, MO, USA  388 Km
2017-04-24  0807  338.0  RYN   Tucson, AZ, USA  2306 Km
2017-04-23  0642  338.0  SHL   Sheldon, IA, USA  663 Km
2017-04-23  0617  338.0  TT     Stuttgart, AR, USA  863 Km
2017-04-21  1845  338.0  UMP   Indianapolis, IN, USA  265 Km
2017-04-22  0233  338.0  ZEM   Eastmain, QC, CAN  1367 Km
2017-04-23  0537  339.0  OP     Thomaston, GA, USA  1040 Km
2017-04-22  0223  340.0  GN     Lexington, KY, USA  506 Km
2017-04-24  0923  340.0  JES    Jessup, GA, USA  1262 Km
2017-04-22  0213  340.0  YY     Mont Joli, QC, CAN  1718 Km
2017-04-22  0237  341.0  CCJ    Springfield, OH, USA  417 Km
2017-04-21  1854  341.0  CQN   Chattanooga, TN, USA  780 Km
2017-04-21  1851  341.0  DB     Dubuque, IA, USA  222 Km
2017-04-24  0532  341.0  DNI    Denison, TX, USA  1168 Km
2017-04-23  0741  341.0  FO     Fort Dodge, IA, USA  523 Km
2017-04-23  0611  341.0  OIN   Oberlin, KS, USA  1075 Km
2017-04-24  0516  341.0  OW   Owensboro, KY, USA  466 Km
2017-04-21  1850  341.0  SB    South Bend, IN, USA  153 Km
2017-04-22  0220  341.0  YYU   Kapuskasing, ON, CAN  958 Km
2017-04-24  0532  342.0  PFT   Pinecreek, MN, USA  1012 Km
2017-04-22  0346  344.0  BKU   Baker, MT, USA  1394 Km
2017-04-23  0602  344.0  IWJ   Blakely, GA, USA  1186 Km
2017-04-22  0332  344.0  JA     Jacksonville, FL, USA  1376 Km
2017-04-23  0722  344.0  SKB   Wichita Falls, TX, USA  1276 Km
2017-04-23  0821  344.0  TKH   Vicksburg, LA, USA  1095 Km
2017-04-21  1859  344.0  UNU   Juneau, WI, USA  193 Km
2017-04-23  0631  346.0  VU     Albemarle, NC, USA  986 Km
2017-04-22  0251  346.0  YXL    Sioux Lookout, ON, CAN  974 Km
2017-04-22  0301  347.0  AFK    Nebraska City, NE, USA  669 Km
2017-04-23  0746  347.0  ATA    Atlanta, TX, USA  1107 Km
2017-04-23  0617  347.0  YK     Yankton, SD, USA  771 Km
2017-04-22  0617  348.0  MC     Mason City, IA, USA  455 Km
2017-04-23  0622  349.0  AAF    Apalachicola, FL, USA  1367 Km
2017-04-23  0606  349.0  GW     Greenwood, MS, USA  927 Km

NDBs this report 48  New NDBs 0

24

QSLs Received / Rave On Radio eQSL

« on: April 25, 2017, 0210 UTC »

Just received from ROR; thanks Rave On!

25

North American Shortwave Pirate / Liquid Radio 6925 AM 0131 UTC 2Apr17

« on: April 02, 2017, 0132 UTC »

w/ mx, JBA

26

MW Loggings / UNID "T" 1650 CW 0431 UTC 17Mar17

« on: March 17, 2017, 1152 UTC »

CW "T" followed by an approx 10 sec DAID heard here with a fair signal in the splatter of a local TIS. 

This is reported as being heard with very strong signals in the FL area.

27

North American Shortwave Pirate / UNID 6925 AM 1840 UTC 31Dec16

« on: December 31, 2016, 1841 UTC »

Very weak here with mx at about +0.110

1847 up to an S1-2 now
1902 off

28

North American Shortwave Pirate / UNID 6925 AM 2315 UTC 17Dec16

« on: December 17, 2016, 2316 UTC »

Have been watching a carrier here for a while.

2315 Now hearing a trace of mx w/ a dance beat.

29

Longwave Loggings / Winter 2016 NDB Logs

« on: December 11, 2016, 1830 UTC »

Recent logs from Downers Grove, Illinois

With 2 significant snows on the ground and frigid temps on the way, it's time to leave Fall behind.

A few from older recordings before they go in the Bit Bucket.  Found a little opening to the
Northeast in last nite's recording and was able to find a couple.  The NH log is USA state #44 here.

2016-12-09  0813  254.0  ZYC   Calgary, AB, CAN  2237 Km
2016-12-06  0951  330.0  2A     South Indian Lake, MB, CAN  1841 Km
2016-12-06  0856  367.0  R5     Pukatawagan, MB, CAN  1823 Km   
2016-12-11  0421  382.0  BT     Burlington, VT, USA  1234 Km
2016-12-11  0414  386.0  GMA   Whitefield, NH, USA  1349 Km    New
2016-12-06  0317  387.0  6E     Grand Manan, NB, CAN  1742 Km
2016-12-11  0441  402.0  LW     Lawrence, MA, USA  1382 Km     
2016-12-11  0344  407.0  CO     Colorado Springs, CO, USA  1462 Km   
2016-12-06  0910  410.0  6Z     La Loche, SK, CAN  2238 Km     

30

North American Shortwave Pirate / Liquid Radio 6925 AM 2143 UTC 19Nov16

« on: November 19, 2016, 2145 UTC »

Been seeing a carrier here - abt S5 - for a while now.  No audio.

And now it's gone at 2148

2202 I do believe that some thumpacious mx has commenced.
2241 still too weak to firmly ID, but shore sounds like LR to me
2338 Still on but very little audio now.

Thanks!