HFH ROHDE & SCHWARZ RECEIVER LOOP antennas - Page 1
Forum section: electronics / rf-microwave

author: py1dkw@yahoo.com
author_rank: Contributor
timestamp: March 12, 2024, 02:08:27 pm
content: Friends, I had bought a wonderful receiver HFH very original, but no power cable and Loop antennas. Need to restore it. Does anybody has an idea how to build a loop for 20 to 30 MHz? I know there was 3 antennas in this set. Thank you for ideas on its restoration too! 73s. Sam

author: RFDx
author_rank: Regular Contributor
timestamp: March 13, 2024, 07:41:22 pm
content: The original loops are part of a resonant input circuit that tunes synchronously with the frequency of the receiver. It's hard if not impossible to build your own loops without knowing the specifications of the original loops. The receiver fortunately has a 60 Ohm input with 12V phantom power supply where a a broadband, active monopole or loop antenna can be connected. The antenna factor of the active monopole/loop has to be known in order to make field strength measurements.

author: py1dkw@yahoo.com
author_rank: Contributor
timestamp: April 16, 2024, 01:10:50 am
content: Well, I was very lucky finding an 8 pin power connector for the HFH, switched it to mains 125 VAC and it is working after 25 years switched off!But the upper bands above 7 MHz are not working. Could be a failure in the the second oscillator ? I could get the diagram from Rohde und Schwarz, the meter in the 20 dB linear and 40 dB log range are not working too. Nice to see it working!

author: coppercone2
author_rank: Super Contributor
timestamp: April 16, 2024, 10:59:50 am
content: would this be empire loop antenna?

author: A.Z.
author_rank: Super Contributor
timestamp: April 16, 2024, 11:15:46 am
content: Quote from: coppercone2 on April 16, 2024, 10:59:50 amare you referring to this one ?https://www.recycledgoods.com/empire-devices-lp-205sc-loop-antenna-12/

author: py1dkw@yahoo.com
author_rank: Contributor
timestamp: April 23, 2024, 11:57:09 pm
content: Unfortunately not. This Empire is a nice loop, but it is not the antenna used by HFH from Rhode & Schwarz. I had a Faraday cage in my Lab and this receiver and another ESH2 were used to measure noise with a Line Stabilization Impedance network, basically a line filter that isolates noise from the mains supply, so you can measure precisely. I had bought some fine Rohde &Schwarz &Schwarz equipment and their support sent me the available manuals. Lots of new capacitors are often needed to restore those equipment!

author: coppercone2
author_rank: Super Contributor
timestamp: April 24, 2024, 01:01:36 am
content: it might work those antenna are used for some kind of official measurements

author: py1dkw@yahoo.com
author_rank: Contributor
timestamp: April 29, 2024, 12:46:03 am
content: Generally the R & S comes with a graph in which the gain in each frequency is given, along with the cable loss discounted too. So HFH is a Field Streght Meter calibrated in dBuV. Very nice!I would like to get in touch with SMDU and SMDU Z1 R &S owners, I will made a specific question, many thnaks, 73s py1DKW

author: py1dkw@yahoo.com
author_rank: Contributor
timestamp: October 05, 2024, 11:40:13 am
content: I would like to contact other hfh owners for exchanging information and diagrams.I could get the 3 antennas loop and base.Nee paint in outside case and had already began exchanging old electrolytic capacitors!Thanks for any reply, regards, 73s, Sam, py1dkw

author: py1dkw@yahoo.com
author_rank: Contributor
timestamp: September 18, 2025, 01:09:13 am
content: Hi Friends and R&S radio fans, I could buy in Germany in my last trip, the 3 loops antennas for my trusty HFH Receiver, exchanged all electrolitics capacitors and many other capacitors as well.Next, one OC28 transistor from the +B power supply was deffective and took one from the. 12v battery inverter and placed in the power supply.yesterday, one Siemens audio output transistor TF28/30 burned, so I replaced both output transistor for AD162, germanium and one of the AD162 is running hotter than the other due to the the different hfe's and different brands.The loop antenna cuts noise even inside home and surprised me. Does anyone has this equipment?