EEVblog® Electronics Community Forum
Electronics => RF, Microwave, Ham Radio => Topic started by: Martin.M on November 26, 2016, 07:32:41 pm
-
what a nice idea, to make a little walk in the garden with a 90 lbs heavy machine, loop antenna and a car battery...
to do some field strengt measurements of not existing radio stations.
let`s do at first a restoration :popcorn:
-
HFH is a extremly sensitive radio system with a defined amplification to readout the field strenght on the large instrument. There is a attenuator switch.
Like the most Rohde + Schwarz test gears of the old time it is inside a silverplated highlight of old engineering, featuring a family of 14 tubes.
The restoration is to do in 3 parts.
Part 1: the instrument self.
The pre owner, may be a HAM, made a manipulation of the wiering to use it as a radio. The most of that I have repaired to get the original functions back, but not complete, still missing 2 of the special coaxial plugs to continue. The function of the socket for the loop antennas is back to life. There was a bad tube, a second was missing, both in the loop system preamplification. This is repaired. Actually the HFH is in a working condition to do measurement (or listening radio...) using it`s loop socket :) To repair is: 60 ohms antenna input with overlay of DC 12V, IF out and some little things to do..
Part 2: missing the Loops.
HFH needs a set of 3 loops and a rotating feet socket plate to come in a working condition. I have to rebuild that complete.
Part 3: external Ground plane antenna missing.
The external ground plane antenna is to rebuild complete. It contains in the socket a germanium driven DC DC converter to feed a tube with stabilized 110V, and a tube as kathode follower to connect the antenna to the 60 ohms cable connection.
A lot of work, also a lot of fun.
greetings
Martin
-
The radio is missing 2 internal connection cables with coaxial plugs , see last picture above.
I am searching for the name of this plugs to buy spareparts. ( 60 ohms)
greetings
Martin
-
Hard to guess dimensions, but are they not a TNC connector, around the same dimensions as a BNC connector but threaded.
-
The radio is missing 2 internal connection cables with coaxial plugs , see last picture above.
I am searching for the name of this plugs to buy spareparts. ( 60 ohms)
greetings
Martin
Martin .. do you know if any other R&S equipment uses these connectors? I have a Polyskop SWOB which I might be able to dismantle and recover some connectors from.
-
Hard to guess dimensions, but are they not a TNC connector, around the same dimensions as a BNC connector but threaded.
Nope!
I did have a few in the shed---not sure if they are still there.
When my old work scrapped the 1970s Siemens TV Transmitters,I remember salvaging them.
From memory they are crimp connectors so may not be reusable.
It seems that some years back German Electronics companies had a rush of blood to the head & decided to cease making older coax connector types.
I guessed they were "Siemens connectors" & Googled,but none of the images that came up looked like these ones.
I can't quite get to the shed at the moment,will have a look ASAP & get back to you.
-
hello Dave,
I don`t like the parting out of old test equipments, that is one of my strictly NoGo`s.
A SWOB is a wonderful working sweeper test place. Bring it back to life please.
Martin
-
I have one of these systems in complete order, but I would like to get documentation to complete the set.
I might fire it up tomorrow and see if its still going.
-
Hi Harb,
I have an English translation (Instruction Book - Edition R 9460/864) of the original German edition R8875/564 scanned in pdf. The english version is without drawings, diagrams and tables of replaceable parts. R&S refer to the German version if such information is needed.
I also happen to have the original German documentation in paper version ( Beschreibung - Ausgabe R10553/1265) which came with my fully functional unit - only missing the antennas.
If interested I can send you the pdf
Rolf
-
That would be fantastic Rolf.......I have zero paperwork, so anything will help when I get back onto it.......I did have a quick look at it and it is pulling a lot of current when I bring it up on the variac and dim bulb, so I guess its going to need some attention for sure.......I will PM you my Email address !
-
about SWOB:
there are 5:
SWOB, SWOBII, III, IV, V
1+2 are identical except 2 have additional UHF, this are tubes SWOB, warm
3 , I use that self, and have the complete manual.
4+5 I don`t know them, no papers or datas.
greetings
Martin
-
Got the Email Rolf........I have printed it out in 2 copies and one lives with the unit itself and the other in the library ! thank you again !!
-
Hi, I have been searching on the web for R&S HFH manuals (english preferrable but can work with German ones if theire is no other option) and I noticed in the blog that you had PDF versions at one point in time. If you still have the files would it be possible to get the files from you? It would be very much appreciated as I just obtained and HFH and would like manuals/schematics so I can more easily troubleshoot a power supply issue.
many thanks in advance,
regards, Peter ?