Although it is not my primary area of interest, I would be grateful to anyone who could offer a suggestion as to why this may be the case.
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I wonder if you have a high noise level? My noise level has recently taken a turn for the worse and even my Wellbrook loop sometimes struggles to hear the beacons because of it. Noise from TV's, computers, phone chargers and anything that uses a SMPS is always worse at the LF end of the spectrum.
How is your wire antenna connected to the Hi-z port? Does the wire come straight into the shack or do you have some kind of coax feeder? If it comes straight in, that may be the problem, as the wire will pick up all the rubbish generated by the stuff in your home. It's also worth checking that you have wired the Hi-z connector as shown in the diagram. Sorry, I can't recall which user guide/cookbook the diagram is in!
Finally, in my experience mini-whips are just as bad as wires when it comes to picking up local noise, which is why I chose the Wellbrook loop. Nine times out of ten, it makes a signal audible when a wire (or my homebrew mini whip) just sees noise.
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Thanks for your responses - I am in a rural location and apart from some "frying" that I believe emanates from overhead three-phase power lines, probably about 50M from my qth, things aren't that bad (I think) and unless ndb's are particularly weak signals, I would have expected to be able to find at least one.
Perhaps my setup isn't as good as I think or would wish it to be, but in general everything seems to work pretty well.
Just for the record, the mini-whip on port A can equal or often exceed the 20M longwire on occasion as conditions vary.
Port B is a h/v/uhf discone, primarily used for v/uhf, but does perform fairly reasonably on HF, with the anticipated roll-off around 3-4MHz.
The longwire is orientated NNW/SSE (my best option) and attached according to the detailed instructions of the supplier and SDRPlay directly to the Hi-z terminal, being brought in via a >5M length of coax.
I did experiment with a 9:1 balun but wasn't sold on it.
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Just one final question, and I hope you won't feel insulted by it. Are all other signals on their expected frequencies? I ask this because a new user on one of the forums was bemoaning 'no signals and images all over the place', and to cut a long story short he had inadvertantly reversed the I and Q channels, putting everything out, plonking stations where they shouldn't be and silence where they should!
Sorry to have to ask, but sometimes it's easy to overlook these things.
The only other thing that springs to mind is de-sensitisation from big sigs in the MW band. Do you have any huge MW sigs there? The LF filter on the RSP2 reaches all the way up to 12 MHz, so everything gets in! It's also worth looking at the LNA gain level and reducing it (or increasing the 'gain reduction' setting).
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I will persevere - all taken aboard - and no you would have to work harder than that to make me feel insulted...
I'm always grateful for any constructive comment.Best Wishes
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Thanks for all the useful advice re NDB reception.
Did a bit of antenna "fettleing," replacing the RAS0Ms mini-whip on port A with another version from the Ukraine (I doubt my ability to make my own) and using it on Port A, I am now able to get pretty good NDB reception (mainly using your preferred AM mode for most) in the 320 - 430 KHZ area.
Generally receiving beacons out to about 200NM from my QTH, with the single exception of Horta in the Azores.
Apart from finding this little antenna a great deal more sensitive in this area, your advice was invaluable.
I recognise that using the HI-Z port would be a better option, but I've dedicated that to the simple end-fed long-wire, which works well, so there I'll leave it (I think).
It was an interesting exercise and ultimately satisfying, but I'll try not to get "hooked."
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Here's a comparison of VLF and NDB reception with a dipole vs. a loop of the same wire length. Actually it's the very same antenna, which is a rather odd contraption I made (by accident) specifically for the RSP, meant to give both good SNR, good wideband capabilities and some built-in attenuation to keep the RSP overloading in check. It's basically a 2x10m dipole with a deliberately not matching balun (the infamous NooElec 9:1 balun) used on both sides of the coax. Putting that thing at the very same spot (in some trees in my case) into a delta (or whatever kind of) loop configuration by simply connecting the wire ends is fundamentally changing its properties of course, to the benefit of low frequency reception.
Here are some animated GIFs to demonstrate:
This shows the impact of the configuration on VLF reception. As you can see, the difference is quite noticeable, spurious signals tend to disappear and actual on-frequency signals get a much better SNR. You can clearly see (and hear of course) the 60 and 77kHz time signals, that were much in the noise before in the dipole configuration.
Here's the NDB band:
The difference is obviously even more pronounced here. The NDB band more or less doesn't exist in the dipole configuration, in the loop configuration I get some additional muck but also a lot of NDBs. Here's what the band typically looks like then:
As you can see, there's quite a lot of them to see clearly, and a lot more of them to pick up in much noise using narrow CW filters and a lot of patience (since they're often fading in and out slowly, interfering with others on a nearby frequency and so on). To my own surprise, I found hunting NDBs a fun challenge, at least for a few days and I'll most likely do it again!
Here's a typical log of 3 days of NDB hunting, they're from all over Europe:
Code: Select all
517 JBR Jaszbereny (Budapest) HU 1069km 514 GO Amari Airbase EST 1093km 492 TBV Trebova CZ 723km 490 WAK Vakarel BG 1684km 488 ILM Illesheim D 528km 485 IA Indija SRB (Belgrad) 1330km 484 HOF Hof D 473km 478 MF Larionovo RUS 1854km* 468 FTZ Fritzlar D 335km 458 LP ? 452 ANS Ansbach D 550km 448 HLV Holesov CZ 803km 448 LQ Landsberg D 698km 438 KO Kozala CRO 1057km 434 MV Melun-Villar. F 755km 433 VNS Castor Platform ESP 1650km 433 CRE Cres CRO 1095km 432 PK Pardubice CZ 656km 431 KBA Karlsruhe D 571km 430 SN St. Yan F 924km 429 LOS Losinj CRO 1123km 428 MUS Nice Cote d'Azur F 1165km 428 CTX Chateauroux F 958km 427 RY Royan F 1179km 426.5 MIQ Mike Ingolstadt D 623km 426 GBG Gleichenberg A 948km 424 PIS Pisarovina CRO 1074km 424 PHG Phalsbourg F 606km 423 ZO Nis SRB 1532km 423 FE Odense DK 421 BL Borlange S 809km 421 MF Halmstad S 379km 419 EMT Epinal F 683km 419 RD Vasteras S 767km 418 MK Mark Calais F 590km 417 AX Auxerre Branches F 792km 417 AH Angelholm S 346km 416 BCS Bacchus S 1052km 415 OL Linkoping Saab S 633km 415 RTB Rothenbach D 542km 414 HD Hestad NOR 818km 414 BRI Bristol GB 824km 414 BOA Bologna I 1069km 412 SE Strasbourg F 622km 410 ETN Etain F 590km 409 SG Satenas S 534km 406.5 BOT Bottrop D 404 Y Kemi FIN 1378km 404 LW Luxembourg LX 404 MRV Merville F 572km 403 OJ Jonkoping S 523km 402 LX Ekilstuna S 745km 401 COD Codogno I 999km 400.5 EJ Esbjerg DK 400 EN Orebro S 690km 400 ONO Oostende BEL 514km 396 YG Enge NOR 1386km 395 GE Billund DK 394 NB Bromma (Stockholm) S 801km 394 NV Nevers F 890km 392.5 TOP Torino I 392 RAN Lappeenranta FIN 388 BR Lyon F 973km 388 COR Corner (Stockholm) S 388 KRU Kruunu FIN 1412km 387 SLT Sylt (aua) D 387 SLV Spa BEL 453km 387 ING Saint-Inglevert BEL 601km 386 O Kardla EST 1005km 386 LNE Linate I 966km 384 TY Torsby S 712km 383.5 GUL Gulpen NL 383 ERK Erken S 865km 382 SBG Salzburg A 762km 381 RG Rygge NOR 596km 380 FLR Trondheim NOR 1038km 380 HO Colmar/Houssen F 681km 379 VEN Venezia I 999km 379 EB Saint Etienne/Boutheon F 1018km 378 RSY Rennesøy (Stavanger) NOR 583km 378 OS Sundsvall S 1041km 377 KN Norkoping S 670km 377 SM Siljan/Mora S 576km 377 ORI Orio Al Serio I 942km 376 HAN Hahn D 478km 376 HP Esbjerg DK 375 RB Orebro S 690km 375 GLA Gland CH 876km 375 CV Calvi/Corsica F 1286km 374.5 ANC Ancona I 1218km 374 BGC Bergerac F 1194km 373 NW Maastricht NL 423km 371 HAA Hamar NOR 753km 371 ODR Odderoy NOR 448km 371 LEV Levaldigi I 1070km 370.5 LB Angelholm S 346km 370 PSA Spessart D 370 BSV Besancon F 792km 369 NL Landvetter S 446km 369 ELU Luxembourg LX 515km 368 RK Roskilde DK 367 BYC Bueckeburg D 367 VAT Vatry F 671km 366 UTH Uthaug NOR 1067km 366 KM Kalmar S 551km 365 VS Vesilahti FIN 1181km 365 LJ Koeln/Bonn D 364 NW Stockholm S 805km 363 PI Poitiers F 1032km 363 OEM Kristianstad S 398km 362 BVK Baatvik NOR 984km 362 NN Ekilstuna S 745km 361 NB Bordeaux F 1235km 361 MAK Mackel BEL 502km 360 ASK Bergen Askoy NOR 739km 360 SR Ensheim D 483km 360 ULV Ulvingen NOR 1290km 359 LOR Lorient F 1109km 358 GRK Grakallen NOR 1036km 357.5 FAL Falconara I 1214km 357 SME Olbia Costa Sardinia I 1470km 357 KD Kolding DK 357 VZ Eelde NL 356 SGO Sagunto ESP 1747km* 355 ONW Antwerpen NL 441km 354 PAD Paderborn D 352.5 DD Oostende BEL 540km 352 PLA Pula CRO 1090km 352 LAA Laarbruch D 335km 352 PSJ Seinajoki FIN 1255km 351 OV Visby S 704km 351 ROT Rotterdam NL 382km 349.5 SZA Solenzara (COR) I 1368km 349 JX Vaxjo S 483km 349 TAR Tarva/Orland NOR 1075km 348 WA Arlanda S 823km 347 CVT Chalons F 654km 346 AU Stauning DK 346 WLU Luxemburg LX 515km 346 LHO Le Havre F 791km 345.5 CF Caslav CZ 648km 345 BN Birkeland NOR 468km 343 KUS Kaunas LIT 973km 342 SL Landvetter S 342 LL Leirin NOR 766km 341 NKS Karlstad S 648km 341 IS Ajaccio (Corsica) F 1358km 339.5 SD ? 338 OA Jonkoping S 523km 337 MY Myggenes FO 1261km 337 LHR Lahr D 648km 336 LT Halmstad S 379km 335 BER Bern CH 805km 334 POY Paris Orly F 750km 333 LE Vasteras S 767km 332 NV Nieuwkoop NL 332 VOG Voghera I 1016km 331 TUR Tours F 943km 330 SO Eelde NL 330 SKS Karlstad S 648km 330 OB Bratislava SLO 879km 329 NMS Namsos NOR 1158km 329 VX Vaxjo S 483km 329 SB Sonderborg DK 327 LNZ Linz A 749km 326 LM Le Mans F 909km 325 PG Trollhättan S 508km 324 ON Norkoping S 670km 324 DP Diepholz D 323 ONC Charleroi BEL 511km 322 OU Stockholm S 805km 321 VO Val D'Or F 653km 320 VE Chabeuil F 1063km 319 VAR Varhaug NOR 536km 318 LP Ronneby S 469km 318 RW Tegel West D 318 CP Parduc HU 974km 317 OZ Kardla EST 1005km 316 TNJ Tounj CRO 1091km 316 IN Sonderborg DK 314 HOL Villacoublay F 752km 314 OZ Brussels Natl BEL 475km 311 LMA Lima (DUS) D 309 DO Dole Tavaux F 824km 307 DIK Diekirch LX 505km 306.5 AV Avord F 902km 300.5 CMP Compagnano I 1269km 300 SC Linkoping S 633km 299.5 KN Svolvaer NOR 1596km 293 OB Brussels BEL 475km 290 ONL Bieset BEL 450km 285 LCF ? S 284 FSB Fassberg D
As you can see, the most distant ones are 1700-1800km away and I've seen logs with even bigger distances, and I can feel a bit of that urge to improve my rig to get even more distant NDBs myself. It think that is the magic of NDB hunting, you have very weak signals from fixed and known locations on published frequencies that sit there and transmit all night, giving you the ideal counterpart for improving your stuff to receive them and improving your skills to search and identify them, which can be quite some detective work. Utterly nerdy fun.
Well yes, some NDBs have been turned off in the past 10 years but surprisingly it seems VORs are more affected by cost reduction attempts than NDBs, which may have to do with the higher maintenance efforts and the fact that many NDBs are still important waypoints on ILS approaches (such as marking the Initial Approach Fix etc.). Most NDBs I still get are located on or near an airport, rather than "enroute"-style beacons. This does matter in that the co-located beacons usually have much less power output.GM4FDM wrote:Perhaps there are less NDBs about than there used to be - I suppose a great deal depends on your location??
But location is important too of course, as well as antenna orientation (which is probably less of an issue with a miniwhip tho).
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