THE WOBBLER

A Mystery Radio Signal

Observations

This page last updated at:
4:00 pm EDT(GMT-4) - October 6, 2007

Latest Wobbler Observations
1100 Strong - 930 Medium - 820, 870 Very weak.

Wobbler Loggings Chart

The Loggings Chart reflects an effort I have made from southeast Florida to check each frequency on which the Wobbler has been heard or reported. The frequencies are checked at least once during the Day and again at Night. When the Wobbler is heard during one of those periods, it is marked accordingly in the Chart.

More frequencies are checked than appear on the chart. Those frequencies which have shown no activity for an extended period are removed from the chart to make it easier to read, but the frequencies are still checked. The current list of frequencies that have been reported and/or are checked is:

560, 570, 590, 610, 620, 640, 680, 730, 750, 770, 810, 820,
870, 910, 930, 950, 960, 1020, 1100, 1110, 1120, 1180, 1220

For more details on these frequencies, check the Reference Materials page.

The relative strength of the Wobbler signal is also indicated in the Chart. The strength is of the Wobbler itself, how widely it varies and how frequently, not necessarily the strength of the broadcast signal with which it is or seemes to be associated. An Xtreme Wobbler could be audible barely above the background noise but wildly oscillating. The range of these strength indications is from barely noticeable and infrequent, to wild excursions that are nearly continuous.

Those loggings marked as Very weak and Weak would require using the special tuning Procedures and some patience to be heard. Very weak means the Wobbler may barely wobble and occur only infrequently. Moderate signals could be heard without special effort only under ideal listening conditions, but would be easily heard using the tuning procedures, though wobbling may be intermittent in nature. Strong indicates the Wobbler is active and could be heard fairly easily along with any other signals on standard table or portable radios. Those occasions where the Wobbler is designated as Xtreme, it is strong and can overwhelm normal signals on the channel with near continuous wobbling activity. Multiple strength entries for a given D or N period represents a trend or anomaly. A Quiet entry indicates a signal that was present during a day or night period, was later found to be there no longer. If no entry appears for a given frequency when there are entries for other frequencies on a given day, there was no Wobbler found on that frequency during the latest checking period logged. If no Wobblers have been heard on any frequency for a given day, the date will be marked with a Q.

Starting on 7/5/05, I began recording the S-Meter reading of the received signal strength according to the NRD-535D receiver, along with the apparent strength of the associated Wobbler as described above.

Checks made with the RX-320D receiver have no signal strength data. Also, there is no phasing for weak signals, which means some Wobblers on occupied channels may have been missed.

This data produces a daily entry that might look something like this:

Dm2v5Nx7s+5

This entry would translate as two daytime checks and two nighttime checks as follows:

Daytime medium Wobbler with signal strength of S-2
Daytime very weak Wobbler with signal strength of S-5
Nighttime extreme Wobbler with signal strength of S-7
Nighttime strong Wobbler with signal strength of S-9+5

The signal strength reading is a best estimate since tuning to hear a Wobbler sometimes does not yeild an obvious peak signal reading. For stations that are under local stations -- such as on 750 which is buried in noise from local 740 IBOC during the day -- the strength can not be determined and is left unspecified. Strength may also not be specified during periods of heavy QRN when readings might be impossible. The strength is offered for whatever possible future value it may prove to hold.

All of these strength observations are subjective and while unintentional, underlying signal strength can affect the ability to evaluate the Wobbler strength. It is difficult to assign an Xtreme Wobbler strength to any signal that can barely be heard by virtue of the very definition of Xtreme.

Additional reports of Wobbler activity can be found on the Comments page, where DXFlorida, IRCA, and NRC member postings are included.

WOBBLER LOGGINGS CHART
FREQ	570	590	620	680	730	750	770	820	870	910	930	950	960	1020	1100	1120	1220
01/03/07	Nw	Nv							Nw		Ns				Nw	Nm
01/08/07		Nw		Nw		Nm	Nm				Nx				Nw
01/11/07			Nw	Nv		Ns			Nm		Ns				Nw	Nv
01/17/07				Dm			Dm		Dm		Dx
01/21/07		Nw						Nw	Nw		Ns				Nm
01/29/07		Nm				Nw					Nx	Nm			Nm	Nm
01/31/07									Dw		Dm				Dm	Dm
02/01/07		Dm		Dw		Dx			Dv		Ds				Dm
02/12/07															Nx²
02/13/07															Nx²
02/14/07						Nm		Nw	Nw		Ns					Nm
02/15/07															Nx²
02/16/07															Nx²
02/17/07															Nx²
02/18/07						Nm			Nw		Nm	Nw			DxNx
02/19/07																	Nv
02/21/07		Dm		Dw	Dv	Dm			Dw		Ds				Dx		Dv
03/07/07				Dm			Dv		Dv		Ds				Dw
03/14/07		Nm		Nw					Nv						Nm
03/24/07		Nw				Nm			Nv						Nv
04/09/07								Nm							Nm
04/21/07						Nv	Nw		Nm			Nw
04/25/07						Nw	Nw					Nm			Nm
05/10/07						Dm						Dw			Dv
05/14/07						Nm		Nv	Nv		Nv				Nm
05/20/07		Nw				Nm					Nv	Nw			Nx
05/23/07	Dw					Dw						Dw			Dm
05/27/07						Dm		Dm	Dw						Dx
05/28/07				Nv		Ns		Nm	Nw						Nx
05/29/07						Ds			Dm		Dm
05/30/07															Ns
06/19/07				Dm		Dw		Ds						Dv	Ds
07/07/07				Nw		Nm		Nw							Ns
07/12/07				Nm		Nm		Nm			Nm	Nm			Ns
08/08/07	Dv			Dm		Dw		Ds			Dw
08/24/07		Nw		Nw	Nw	Nw	Nw	Nv	Nv		Nv				Ns
09/20/07															Ds²
10/02/07				Dw					Dw	Dw	Ds				Dx
10/04/07											Dm				Dx
10/06/07								Dv	Dv		Dm				Ds

FREQ	570	590	620	680	730	750	770	820	870	910	930	950	960	1020	1100	1120	1220

Legend: D-Day / N-Night / Qq-quiet / v-very weak / w-weak / m-moderate / s-strong / x-xtremely strong

º Thunderstorms and/or static (QRN) may have prevented checking some Wobbler stations.
¹ No checks made. Also, skipped dates were not checked.
² Special monitoring, other frequencies not checked. A 'q' here means the station went silent.
³ Extreme local noise prevents hearing some stations.

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© W. Curt Deegan, 2007