Tuning Unit (Aerial) Type 7180 - UK Vintage Radio Repair and Restoration Discussion Forum

rogerggbr · 12th Oct 2021, 9:53 pm

I have one of these, ref 10D/19238, 24-LRU-52B, Serial no. E92. Acquired a long time ago and languishing in my garage for well over 30 years. Probably found at a rally or junk sale, never been used by me.
I did find a thread on here from over 10 years ago with the instruction "don't mess with it".
But it has been messed with before I got it as it has a pair of SO239s on the back. Looks clean inside, otherwise I have not touched it. All the knobs turn, switches switch.
Is it of any real use to anyone rather than me mess with it? I think originally I intended to just use it as a manual tuner (and it was probably sold to me on that basis) but life got in the way....
I don't want to ruin it if it can have a better future, just not sure where other than a museum. The manual is available online (the copy I found is from 1955, 56 and 63).
Comments and suggestions appreciated.

G6Tanuki · 13th Oct 2021, 6:30 pm

It's an intriguing circuit, RF-wise: ignoring the auto-tune part it's basically a high-pass-Pi-filter [L:C:L] as opposed to the more-usual C:L:C variety.

I guess the requirements of feeding electrically-short low-HF-band antennas on the Blackburn Beverley made this a sensible way to go.

[Part of me would like to take it off your hands and use it to tune my 'short' 40-foot end-fed wire I use with my Eddystone 840A bedside radio].

12th Oct 2021, 9:53 pm	#1
rogerggbr Triode Join Date: Apr 2021 Location: Huddersfield, West Yorkshire, UK. Posts: 12	Tuning Unit (Aerial) Type 7180 I have one of these, ref 10D/19238, 24-LRU-52B, Serial no. E92. Acquired a long time ago and languishing in my garage for well over 30 years. Probably found at a rally or junk sale, never been used by me. I did find a thread on here from over 10 years ago with the instruction "don't mess with it". But it has been messed with before I got it as it has a pair of SO239s on the back. Looks clean inside, otherwise I have not touched it. All the knobs turn, switches switch. Is it of any real use to anyone rather than me mess with it? I think originally I intended to just use it as a manual tuner (and it was probably sold to me on that basis) but life got in the way.... I don't want to ruin it if it can have a better future, just not sure where other than a museum. The manual is available online (the copy I found is from 1955, 56 and 63). Comments and suggestions appreciated. Attached Thumbnails

13th Oct 2021, 6:30 pm	#2
G6Tanuki Dekatron Join Date: Apr 2012 Location: Wiltshire, UK. Posts: 13,998	Re: Tuning Unit (Aerial) Type 7180 It's an intriguing circuit, RF-wise: ignoring the auto-tune part it's basically a high-pass-Pi-filter [L:C:L] as opposed to the more-usual C:L:C variety. I guess the requirements of feeding electrically-short low-HF-band antennas on the Blackburn Beverley made this a sensible way to go. [Part of me would like to take it off your hands and use it to tune my 'short' 40-foot end-fed wire I use with my Eddystone 840A bedside radio]. __________________ I'm the Operator of my Pocket Calculator. -Kraftwerk.