Kokusai mechanical filter question - UK Vintage Radio Repair and Restoration Discussion Forum

PA3DAF, Erwin · 27th Jan 2023, 6:23 pm

Hello to all,

I tried to find info about a Kokusai mechanical filter type "MF-455-12GZ". There is a lot of info about the MF-455-10GZ but nothing about the 12GZ. Who can help me?

TIA

Erwin, PA3DAF

HamishBoxer · 27th Jan 2023, 6:39 pm

MF-455K Series Specifications Min. Band- width at 6 dB Attenuation (kHz) 2.0 3.0 Max. band- Standard Gain width at 60 dB at 4 Millimhos Working Temperature Range (QC) O to +70 O to +70 TYPE MF-455-10CK MF-455-15CK Center Max.

All I could find, they all sound a bit similar.

G6Tanuki · 27th Jan 2023, 6:39 pm

I wonder if the "10" or "12" defines the bandwidth?

Restoration73 · 27th Jan 2023, 6:57 pm

On Radiomuseum 10 = 2kHz BW, and 15 = 3kHz, so I wonder if 12 is the very popular
2.7kHz BW.

Terry_VK5TM · 27th Jan 2023, 11:08 pm

This is as much as I have been able to find so far "12-element mechanical filter called MF-455-12GZ is also listed in the standard table" from here https://ala1530s.blogspot.com/2013/05/blog-post_22.html

It's in Japanese so you will need to translate it.

27th Jan 2023, 6:23 pm	#1
PA3DAF, Erwin Diode Join Date: Mar 2022 Location: Huissen, The Netherlands Posts: 7	Kokusai mechanical filter question Hello to all, I tried to find info about a Kokusai mechanical filter type "MF-455-12GZ". There is a lot of info about the MF-455-10GZ but nothing about the 12GZ. Who can help me? TIA Erwin, PA3DAF

27th Jan 2023, 6:39 pm	#2
HamishBoxer Dekatron Join Date: Aug 2007 Location: W.Butterwick, near Doncaster UK. Posts: 8,712	Re: Kokusai mechanical filter question MF-455K Series Specifications Min. Band- width at 6 dB Attenuation (kHz) 2.0 3.0 Max. band- Standard Gain width at 60 dB at 4 Millimhos Working Temperature Range (QC) O to +70 O to +70 TYPE MF-455-10CK MF-455-15CK Center Max. All I could find, they all sound a bit similar. __________________ G8JET BVWS Archivist and Member V.M.A.R.S Last edited by HamishBoxer; 27th Jan 2023 at 6:44 pm.

27th Jan 2023, 6:39 pm	#3
G6Tanuki Dekatron Join Date: Apr 2012 Location: Wiltshire, UK. Posts: 12,410	Re: Kokusai mechanical filter question I wonder if the "10" or "12" defines the bandwidth? __________________ "Acht Nul Noyyun Zwo Funnuf" -Magdeburg Annie.

27th Jan 2023, 6:57 pm	#4
Restoration73 Nonode Join Date: Jun 2013 Location: Surbiton, SW London, UK. Posts: 2,765	Re: Kokusai mechanical filter question On Radiomuseum 10 = 2kHz BW, and 15 = 3kHz, so I wonder if 12 is the very popular 2.7kHz BW.

27th Jan 2023, 11:08 pm	#5
Terry_VK5TM Nonode Join Date: Oct 2010 Location: Tintinara, South Australia, Australia Posts: 2,117	Re: Kokusai mechanical filter question This is as much as I have been able to find so far "12-element mechanical filter called MF-455-12GZ is also listed in the standard table" from here https://ala1530s.blogspot.com/2013/05/blog-post_22.html It's in Japanese so you will need to translate it. __________________ Terry VK5TM https://www.vk5tm.com/