I was wondering if there's a way without using test equipment to find out approximately what the sensitivity (in millivolts per meter / microvolts per meter, and dB above noise floor) of my Panasonic RQ-SW20 is, and the selectivity (in dB attenuation at +/- multiples of 10 (or 9) kHz? Also, I'd like to know how to figure out how the Select-A-Tenna (I have one) changes the results, numerically. Problem is I don't have a field strength meter, and really don't want to take the radio apart. It has no antenna input terminals.
A few examples:
near 34°46'N and 116°57'W (all at or close to high noon to minimize skywave):
980 KFWB is barely readable.
640 KFI has some static, but is fairly easily listenable, barely lighting the tuning indicator. At +/- 10 kHz it's barely detectable.
760 KFMB has pretty much full quieting on channel, lights tuning indicator +/- 10 kHz, and is weak, but still quite audible +/- 20 kHz.
using a select-a-tenna, 760 KFMB will light the tuning indicator up to 820 kHz, then is audible up to somewhere in the 900s or so, before returning around 1520kHz as a somewhat weak second harmonic. Selectivity on the bottom side is markedly superior, as by 720 the tuning indicator is extinguished, and when going past XETRA 690, 760 makes no more appearances.
Without the select-a-tenna, 600 KOGO is strong on channel, and would be full quieting if it weren't for IBOC interference. On 610, the IBOC sideband completely wipes out 600's program audio. On 620, there's still a hint of IBOC, but by 630 everything's gone. With the SAT tuned to the IBOC, the hash goes up to about 630 or so, and with the sat tuned to 600, KOGO's audio is on top of the iboc even on 610, and is audible into the upper 600s.
At night without the select-a-tenna, 760 KFMB is lit up to 780.
Before the Santee transmitter was taken down, in the daytime 1170 KCBQ would light the indicator to 1200, and be fairly easily audible up to 1230, and maybe 1250 or 1260 or so.
Anyone know how I could figure out the sensitivity/selectivity rating(s) of my RQ-SW20?
One reason I ask, is because how well of a signal I want to put in a part 15 station in a given area is based on how it would be received using only the internal ferrite bar loopstick on the SW20, assuming I'm transmitting the same (band)width signal that a commercial C-Quam station using a 10kHz response usually uses.
For example, if I'm in a moderately sized building, or outdoors in a fairly small area in a semi-public gathering, using a portable AMS transmitter without much of an antenna (thereby operating under the field strength rule instead of the antenna+power rule), within all parts of the building and/or within a few hundred feet of the transmitter (especially if outdoors, or if the TX is in a building and there are listeners outside the building), I want to have full receiver quieting on-channel, and have the tuning indicator lit about 1 or 2 channels off frequency, which would make for a fairly strong signal, hopefully with enough signal to noise ratio to make a CD quality recording from a receiver.
For a main part 15 operation in which I have an antenna/ground system, I want full quieting and +/- 10kHz tuning indicator lit at least a mile from the antenna, if possible, and within my 1/2 acre back yard, well, I'm quite sure it would be a VERY strong signal.
A few examples:
near 34°46'N and 116°57'W (all at or close to high noon to minimize skywave):
980 KFWB is barely readable.
640 KFI has some static, but is fairly easily listenable, barely lighting the tuning indicator. At +/- 10 kHz it's barely detectable.
760 KFMB has pretty much full quieting on channel, lights tuning indicator +/- 10 kHz, and is weak, but still quite audible +/- 20 kHz.
using a select-a-tenna, 760 KFMB will light the tuning indicator up to 820 kHz, then is audible up to somewhere in the 900s or so, before returning around 1520kHz as a somewhat weak second harmonic. Selectivity on the bottom side is markedly superior, as by 720 the tuning indicator is extinguished, and when going past XETRA 690, 760 makes no more appearances.
Without the select-a-tenna, 600 KOGO is strong on channel, and would be full quieting if it weren't for IBOC interference. On 610, the IBOC sideband completely wipes out 600's program audio. On 620, there's still a hint of IBOC, but by 630 everything's gone. With the SAT tuned to the IBOC, the hash goes up to about 630 or so, and with the sat tuned to 600, KOGO's audio is on top of the iboc even on 610, and is audible into the upper 600s.
At night without the select-a-tenna, 760 KFMB is lit up to 780.
Before the Santee transmitter was taken down, in the daytime 1170 KCBQ would light the indicator to 1200, and be fairly easily audible up to 1230, and maybe 1250 or 1260 or so.
Anyone know how I could figure out the sensitivity/selectivity rating(s) of my RQ-SW20?
One reason I ask, is because how well of a signal I want to put in a part 15 station in a given area is based on how it would be received using only the internal ferrite bar loopstick on the SW20, assuming I'm transmitting the same (band)width signal that a commercial C-Quam station using a 10kHz response usually uses.
For example, if I'm in a moderately sized building, or outdoors in a fairly small area in a semi-public gathering, using a portable AMS transmitter without much of an antenna (thereby operating under the field strength rule instead of the antenna+power rule), within all parts of the building and/or within a few hundred feet of the transmitter (especially if outdoors, or if the TX is in a building and there are listeners outside the building), I want to have full receiver quieting on-channel, and have the tuning indicator lit about 1 or 2 channels off frequency, which would make for a fairly strong signal, hopefully with enough signal to noise ratio to make a CD quality recording from a receiver.
For a main part 15 operation in which I have an antenna/ground system, I want full quieting and +/- 10kHz tuning indicator lit at least a mile from the antenna, if possible, and within my 1/2 acre back yard, well, I'm quite sure it would be a VERY strong signal.