VACUUM TUBE 350B

QRO questions

under construction ...

S-points for frequencies below 30 MHz:

Signal strength	Relative intensity	Received voltage		Received power (Zc = 50 Ω)
S1	–48 dB	0.20 μV	–14 dBμV	790 aW	–121 dBm
S2	–42 dB	0.40 μV	–8 dBμV	3.2 fW	–115 dBm
S3	–36 dB	0.79 μV	–2 dBμV	13 fW	–109 dBm
S4	–30 dB	1.6 μV	4 dBμV	50 fW	–103 dBm
S5	–24 dB	3.2 μV	10 dBμV	200 fW	–97 dBm
S6	–18 dB	6.3 μV	16 dBμV	790 fW	–91 dBm
S7	–12 dB	13 μV	22 dBμV	3.2 pW	–85 dBm
S8	–6 dB	25 μV	28 dBμV	13 pW	–79 dBm
S9	0 dB	50 μV	34 dBμV	50 pW	–73 dBm
S9+10	10 dB	160 μV	44 dBμV	500 pW	–63 dBm
S9+20	20 dB	500 μV	54 dBμV	5.0 nW	–53 dBm
S9+30	30 dB	1.6 mV	64 dBμV	50 nW	–43 dBm
S9+40	40 dB	5.0 mV	74 dBμV	500 nW	–33 dBm
S9+50	50 dB	16 mV	84 dBμV	5.0 μW	–23 dBm
S9+60	60 dB	50 mV	94 dBμV	50 μW	–13 dBm

Collins Radio 51S-1

                                                       COLLINS  RADIO 51S-1 HF Receiver


Large Round Emblem 1972  S/N 8435 ANAMOSA MADE

There were two types of meters  used it the 51S-1, one is made by Bartlett, and the other one, is made by Honeywell. 

The Bartlett does not have any brand printed on it but the Honeywell has the Honeywell name stamped in the lower left side

There were a few early 51S-1s with a Simpson Meter face but very few had this meter which is slightly different than the two mentioned . 
Mine is the Bartlett's prod.

This is not an S-meter, this is RF input level meter, but this is good for communications receivers.

 Listening N. America

Listening Uruguay from Greece  16 Sept 19