Radio direction finder, Samos

[bracer]

Hi!

I have some troubles understanding the german RDF-equipment like the Samos.
My question is what is the difference between "Suchen" and "Peilen"?

Here's the Samos:


The switch I am wondering about:


The indicator shows different values depending on if your in "Suchen"-mode or "Peilen"-mode.


Photos are from this page: https://www.kriegsfunker.com/radios/samos.php

Thanks for any insights!!
Cheers!

[Thorsten Wahl]

Suchen = finding a frequency in use
Peilen = direction finding

[bracer]

Hi Thorsten!

Thank you! That makes sense.
Do you happen to know what the numbers on Suchen mode means?
10^1, 10^2, 10^3, 10^4, 10^5?

Is it the frequency range 10-100000hz?

All the best!
/Daniel

[Steve Crandell]

I think it's just signal strength. To determine frequency they would need a tuning knob, and if it was tunable they wouldn't pick up a signal unless they happened to be on the correct frequency. I suspect this device simply uses a diode detector and while it is much less sensitive than a tunable radio receiver it has the advantage of picking up a large band of signals.

Just my two cents. I used to maintain radio intercept equipment in the USN, but that was many years ago and I could be wrong. I wonder what the other screen is in the bottom center along with what could be a volume or even a tuning knob. I really don't know how they did the job in those early days.

[marcelo_malara]

Yes, the powers of 10 should be decibels, a measure of signal power. The peilen scale should be related to bearing, but I can not imagine what the numbers are. A scale in any instrument should tell the physical magnitude it measures, in the case of the decibels they are not a magnitude in itself, because it is just the relationship received power/transmitted power, or the relation received power/reference power. The only angular magnitude not named is the radian, where 2 * 3.14 radians = 360°, the word radian is omitted in physics, but I would no dare say the scale is actually radians.

[bracer]

I think it's just signal strength. To determine frequency they would need a tuning knob, and if it was tunable they wouldn't pick up a signal unless they happened to be on the correct frequency. I suspect this device simply uses a diode detector and while it is much less sensitive than a tunable radio receiver it has the advantage of picking up a large band of signals.

Yes, the powers of 10 should be decibels, a measure of signal power. The peilen scale should be related to bearing, but I can not imagine what the numbers are. A scale in any instrument should tell the physical magnitude it measures, in the case of the decibels they are not a magnitude in itself, because it is just the relationship received power/transmitted power, or the relation received power/reference power. The only angular magnitude not named is the radian, where 2 * 3.14 radians = 360°, the word radian is omitted in physics, but I would no dare say the scale is actually radians.

Yes, it might be signal power both of the scales. Here's what the manual says + a google translation:

"Ist das zu suchende Zeichen in seiner Amplitude unbekannt oder stark schwankend, so wird der Kippschalter "Peilen - Suchen" auf "Suchen" geschaltet. Der Skalenverlauf des instrumentes ist in diesem Fall annähernd logaruthmisch und umfabt 5 dekaden. Ist das Zeichen verhältnismäBig konstant, so wird der Schalter auf "Peilen" geschaltet. Der Verlauf der Instrumentskala ist dann annähernd linear und umfabt eine dekade."

Translated to:
"If the amplitude of the character to be searched for is unknown or fluctuates strongly, the toggle switch "Peilen - Search" is switched to "Search". In this case, the scale of the instrument is approximately logarithmic and spanned 5 decades. If the symbol is relatively constant, the switch is switched to "peilen". The course of the instrument scale is then approximately linear and spans a decade."

I wonder what the other screen is in the bottom center along with what could be a volume or even a tuning knob. I really don't know how they did the job in those early days.

That seems to be the frequency range and bands according to the caption on the webpage.


But still I don't understand if you still have to choose a frequency to scan when using "Peilen".
Maybe the above makes more sense to some of you.

[Steve Crandell]

Sure, now it's perfectly clear. The big square display is the frequency being tuned to, with the large knob controlling the receiver's frequency. It's basically just a radio receiver like you might have at home or in your car. Once the frequency is tuned to, you rotate the antenna to the strongest signal and the bearing the antenna points to is your target bearing.