Siemens D2155 Pegelmesser
 

A Selective Level Meter is basically a Spectrum Analyzer without the swept display and is used for signal level measurements at spot frequencies in a defined bandwidth. The Siemens D2155 Pegelmesser is a Classic rather than Vintage instrument, dating from the 70s, and is one of the series where the SLM was paired with a signal source having accurate level calibration.
The D2155 was paired with W3155, covering 200Hz to 620kHz
The D2019 was paired with W3109, covering 200Hz to 6MHz
The D2108 was paired with W2108, covering 200Hz to 30MHz
The preceding series included the D2006 and W2006, covering 10kHz to 17MHz

Other makes of SLM were available, as discussed in the thread Wandel & Goltermann manuals. but I have a particular fondness for the Siemens models.

I have at last found das Handbuch für mein Pegelmesser, which continues to work well, so now I will be able to maintain and calibrate it.

Re: Siemens D2155 Pegelmesser
 

They were well-built instruments and can be used for LF and VLF radio reception EXCEPT there is no useable AGC as SLMs either have manual range switches or autorange in big steps.

The connectors on it are known as Siemens 3-pole being a balanced pair and ground. I still use them for 13.8v distribution in my shack. Each pole is a normal 4mm banana. You probably have a few switched impedance levels and maybe a high-Z bridging mode.

But remember, das gerate ist nicht für gefingerpoken!

David

Re: Siemens D2155 Pegelmesser
 

These sets are used in Carrier Telephony.
They have a too small bandwidth to be useful to act as radio.
I spent many years working with them in Philips Telecom Industries
The pictures show my (ex) work spot with W&G sets
Jard N.

Re: Siemens D2155 Pegelmesser
 

Don't they have a 3kHz channel filter?

I was thinking in terms of SSB and CW transmissions.

I was involved in SLMS and the Baseband Analyser development at HP.

David

Re: Siemens D2155 Pegelmesser
 

As I recall ...,

The lower featured SLMs for FDM testing had narrow, (typically 20 Hz) and wideband BW selectivity.
The more featured test sets had narrow, 3.1 KHz, 50 KHz, (normally 48 KHz to be precise) and wideband.

You could carry out most baseband maintenance and fault clearance on smaller links up to say 120 or 240 channels with just the lower featured SLMs, as you are normally testing and checking single pilots and test tones of 1000Hz injected into single channels.


The narrow band selection wss used for "pilots" and single test tones within a channel, or anywhere in the baseband.
It was also used for testing the 3825 Hz inband E&M signalling within a single channel.

The 3.1 KHz selectivity was used for tech monitoring of speech within one channel.
It was 3.1 KHz or so, to avoid any influence from inband signalling tones, and normally had reduced response up to about 250 Hz.

The 50 KHz selectivity was used sometimes for the "Busy Hour Loading" average level across a Group.

The wideband had multiple uses, and extended to low AF frequencies.

The demodulation for the 3.1 KHz channel usually could be inverted to allow for both LSB and USB as found in the various secttons of the Baseband, and depending on manufacturer's configuration.

Re: Siemens D2155 Pegelmesser
 

3.1kHz filtering was also used for power measurement of individual channels. There was a big thing about 'Hot talkers' gobbling up unfair amounts of the system dynamic range and increasing intermods and noise floor for everyone else.

David

Re: Siemens D2155 Pegelmesser
 

Thanks for the description of their use in carrier telephony systems. They tend to be quite unsuitable for use a domestic or Dx receivers. The bandwidth figures are quoted for 0.5, 3, and 50dB attenuation, quite the opposite of the 'brick wall' you need for good quality listening or dx. The quoted figures are ~20Hz or 3.1kHz at 3dB. The audio output is provided to help to find and confirm a carrier, and is mixed down to a beat tone of 1kHz, so CW reception is possible.

The co-ax input connector is a MUSA video type, the headphone output is banana sockets. I attach the catalogue page.

Re: Siemens D2155 Pegelmesser
 

There are also WECO connectors which resemble MUSA ones but aren't compatible. You come across them on variants intended for the US (Bell) market They usually get used on wider bandwidth 75 Ohm ports.

David

Re: Siemens D2155 Pegelmesser
 

Catalogue page at better resolution

Re: Siemens D2155 Pegelmesser
 

Hi Julian,

I am using a Siemens D2055 SLM on the bench at present for coms receiver IF troubleshooting.
Very useful devices, and with a large easy to read level meter.

Although it is nominally 75 ohm input (inter alia), the mismatch loss 75 to 50 ohms and vice versa is only 0.19 dB, and can be allowed for if required, which is almost never in practice.

As Wrangler has said, we, over here in Australia, also just referred to the input balanced connector as "Siemens 3 pin".
For normal unbalanced work, I have made up some coaxial adaptors, S3Pin plug to BNC50 socket.

If ever you have a digitised copy of your handbook, may I please have a copy?

Re: Siemens D2155 Pegelmesser
 

@Radio1950 - I don't have any service info for the D2055 but I have the D2006 and its manual. Both models are from the same series with the film-scale dial. They have no modules in common, but several modules must be near identical. If a mod could re-open your earlier thread Siemens D2055 Selective Level Meter Service Manual? we could compare the two and probably identify which modules serve the same functions.

Re: Siemens D2155 Pegelmesser
 

As discussed, SLMs are not very flexible for use as radio receivers, but I recall using spec an's that included a demodulator module and had a speaker. For level measurements you might enjoy to use an EMC Level Meter like this Rhode und Schwarz ESVS 10 which demodulates AM, FM and CW in various bandwidths.

Re: Siemens D2155 Pegelmesser
 

Hi Julian

I was hoping that you might have a Service Manual for your D2155 so as to compare with my D2055, and maybe discover useful similarities. I am doubtful, but it is worth a try.

Thanks

Re: Siemens D2155 Pegelmesser
 

@Radio1950 - the D2155 has absolutely nothing in common with the D2055. I do have the manual for the D2006 which is from the same period as the D2055 with film-scale dials (there are separate dials for MHz and kHz). They have no modules with the same type numbers, but they both have IFs of 2.4MHz and 100kHz, the 2nd conversion osc are at 2.3MHz so my guess is the designs are very close for these modules and possibly also the two mixers.
If you care to email me with photos of the 3 or 5 boards I can check if they look the same as mine before I start scanning the manual.

Re: Siemens D2155 Pegelmesser
 

The D2019 uses a connector I don't recognise, probably not a WECO? It takes a 4mm banana for the inner, but it is recessed 24.5mm into the 12.5mm dia. outer

Re: Siemens D2155 Pegelmesser
 

Hi again

I had a look for an online manual for a D2155.
I found that it uses different boards and a somewhat different design to my D2055, so I think we can forget about it now, but thanks anyway.

That mystery connector is vaguely familiar, but I cannot remember anything else.
Metrix used a similar coax connector on early RF Sig Gens but the centre pin gender was reversed.

It was a good thing that most manufacturers started to use 1.6/5.6 connectors for "sync" etc with SLMs

Re: Siemens D2155 Pegelmesser
 

That's not a WECO. Reminds me of the one Bruel & Kjaer test gear used.

David

Re: Siemens D2155 Pegelmesser
 

Curious about the WECO conns, I was pleased to see that jeffpeletz posted on the hparchive group today that he has just uploaded some very artistic high-definition photos of "653A test oscillator with Weco outputs for telcos and video testing" at ***********
These are of course different from the Siemens conns