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The one I have, that's blown, has tiny toggle switches.
Bruce Hawkins AC6DN
On Saturday, July 13, 2024 at 07:29:25 AM CDT, Martin via groups.io <martin_ehrenfried@...> wrote:
On Fri, Jul 12, 2024 at 03:13 PM, Tom Twist wrote: It's been many years since I tried to get it repaired,
but as far as I remember, these are custom switches, where a gold plated
slider is pressed onto the PCB. Ah OK, that explains how they managed to get the performance up to 1GHz. It's a variation of the construction method used in the push button types. Regards, Martin
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I have a blown Kay attenuator. So I assume the schismatic in in the linked service manual. This should be very helpful. When I get unpacked from moving.
Bruce Hawkins AC6DN
On Thursday, July 11, 2024 at 08:22:35 AM CDT, Zack Widup <w9sz.zack@...> wrote:
Thanks Martin. I have had the unit open and I knew they had more than just resistors in each stage. I saw a lot of capacitors, too. I figured they went to some trouble to provide frequency compensation to give it the 1 GHz range.
Zack W9SZ
On Thu, Jul 11, 2024 at 2:48?AM Martin via <martin_ehrenfried= [email protected]> wrote: Hi Zak,
You may be able to obtain some SMA's with a larger mounting flange and swap out the connectors.
I have attached a Kay service handbook, so that you can see the internal construction, and also how much effort is required to provide effective screening and frequency compensation, if you want to build something similar.
Regards,
Martin
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On Fri, Jul 12, 2024 at 03:13 PM, Tom Twist wrote:
It's been many years since I tried to get it repaired,
but as far as I remember, these are custom switches, where a gold plated
slider is pressed onto the PCB.
Ah OK, that explains how they managed to get the performance up to 1GHz. It's a variation of the construction method used in the push button types. Regards, Martin
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Hi Martin
Thanks for your reply.
I'm afraid it's not that easy. It's been many years since I tried to get it repaired,
but as far as I remember, these are custom switches, where a gold plated
slider is pressed onto the PCB.
The broken parts are the handles, so I think the electrical parts are ok.
I suppose I could machine new ones, but that is a job I'm not looking forward
to. In the mean time, I have aquired several other attenuators, so I'll probably
let it rest.
Tom, LB8X
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On Thu, Jul 11, 2024 at 07:01 PM, Tom Twist wrote:
Do you know of a way to get spare parts?
Hi Tom, Sorry no. I'm amazed that Kay didn't respond, maybe try phoning them instead ? But in most cases, the actual switches will have markings on them that indicate the original manufacturer. If you can't get the original types, then you should be able to substitute with a similar looking item. Either way it will disturb the characteristics, but if you perform the work carefully it shouldn't mess? it up too much. If you don't have any luck, send me a PM with some photographs of a switch, and I'll see if I can identify it for you. Regards, Martin
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Martin
I have a damaged Kay attenuator, looking like the 460, where some
of the switches are broken.
I have approched Kay Electric Co by email, asking for spare parts,
but I never got an answer.
It's a pity, because they are nice units.
Do you know of a way to get spare parts?
regards
Tom, LB8X
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Thanks Martin. I have had the unit open and I knew they had more than just resistors in each stage. I saw a lot of capacitors, too. I figured they went to some trouble to provide frequency compensation to give it the 1 GHz range.
Zack W9SZ
On Thu, Jul 11, 2024 at 2:48?AM Martin via <martin_ehrenfried= [email protected]> wrote: Hi Zak,
You may be able to obtain some SMA's with a larger mounting flange and swap out the connectors.
I have attached a Kay service handbook, so that you can see the internal construction, and also how much effort is required to provide effective screening and frequency compensation, if you want to build something similar.
Regards,
Martin
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On Wed, Jul 10, 2024 at 10:50 PM, W0LEV wrote:
Push buttons get pretty cranky over time and use.? Real toggle switches are more reliable.?
Hi Dave, It depends on the construction, but the cheap ones can be problematic. The advantage of the push button designs is that the "switch" mechanism can be the actual PCB with a sliding contact moving across it. If gold-plated it can be very reliable, as the "swiping" action cleans the contacts. Most step attenuators in older test kit end to use the equivalent construction, with an electromagnet operating the switch mechanism. This is an example from a 1970's Marconi signal generator.  However, more recent designs use either the very small (TO5 transistor can) Teledyne signal relays, or fully electronic devices, the latter can introduce other problems.  The Teledyne relays are now becoming ridiculously expensive, close on the $100 mark each when new. A related anecdote. A digital microwave link project, I once worked on, used these types of relays to switch over 2MB circuits between main and reserve equipment. Unfortunately, it developed a fault during the commissioning phase, which resulted in all the channels, at all the sites, rapidly switching between main and reserve. This wasn't spotted when it occurred, and after about a week of buzzing away, they all started to fail, as they had reached the end of their specified life of switching cycles. The poor technician who was tasked with the job, spent two weeks on the various sites, replacing more than 500 of them. We kept the dud ones in the office, in a large glass jar, and it was used as a "wooden spoon" award, that was presented to however had "messed up" on a project, until it could be passed on to the next "winner". Regards, Martin
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SMA with large mounting flange, currently on ebay
Regards,
Martin
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Hi Zak,
You may be able to obtain some SMA's with a larger mounting flange and swap out the connectors.
I have attached a Kay service handbook, so that you can see the internal construction, and also how much effort is required to provide effective screening and frequency compensation, if you want to build something similar.
Regards,
Martin
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I have a Kay 475 attenuator I bought on eBay. It has toggle switches and a 0 to 100 dB attenuation range. The frequency range listed on it is 0 to 1000 MHz. It seems to be pretty accurate. It has TNC connectors, so I had to get some TNC to BNC and TNC to SMA adaptors.
Zack W9SZ
Push buttons get pretty cranky over time and use.? Real toggle switches are more reliable.?
Dave - W?LEV
On Wed, Jul 10, 2024 at 8:52?PM Martin via <martin_ehrenfried= [email protected]> wrote: On Wed, Jul 10, 2024 at 04:27 PM, Dean Kiefer wrote:
Pacific Antenna has a 41db in 1 db steps kit
Hi Dean,
I think it's fine for HF use, they claim up to 200MHz, but I'd suggest 30MHz is more reasonable before the performance tails off.
Ideally, it needs to be in a metal box, otherwise you will get signals leaking in (and out), and I suspect it wouldn't achieve 40dB isolation whilst in a plastic case.
You can obtain push button binary value step attenuators, in various power ratings and step sizes, rated up to a few GHz from AliExpress, with prices starting at around $25 USD for a 2w 0-30dB version.
Search for "0-90db/60/30 button adjustable / step attenuator"
Regards,
Martin
--
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Dave:
I have a somewhat different view of the issue.? I've watched this
and previous threads on this same topic where the answer always
seems to be fixed attenuator, fixed attenuator, fixed attenuator,
as if some form of step/variable attenuator did not exist.? Fixed
attenuators seemed to be the only thing mentioned here.
I believe this is the first time someone has ventured something
other than a fixed attenuator.? I've been around long enough
(maybe too long), where I have step attenuators and barrel
attenuators (Texscan) to handle these needs.? You hook it up once
and make the measurements.? No more beating those SMA connectors
to death as you attempt to change values.
Ok, back in my corner...
Regards
Charlie, k1xx
On 7/10/2024 6:50 PM, W0LEV wrote:
toggle quoted message
Show quoted text
Push
buttons get pretty cranky over time and use.? Real toggle
switches are more reliable.?
Dave
- W?LEV
On Wed, Jul 10, 2024 at
8:52?PM Martin via <martin_ehrenfried= [email protected]>
wrote:
On
Wed, Jul 10, 2024 at 04:27 PM, Dean Kiefer wrote:
Pacific Antenna has a 41db in 1 db steps kit
Hi Dean,
I think it's fine for HF use, they claim up to 200MHz, but I'd
suggest 30MHz is more reasonable before the performance tails
off.
Ideally, it needs to be in a metal box, otherwise you will get
signals leaking in (and out), and I suspect it wouldn't
achieve 40dB isolation whilst in a plastic case.
You can obtain push button binary value step attenuators, in
various power ratings and step sizes, rated up to a few GHz
from AliExpress, with prices starting at around $25 USD for a
2w 0-30dB version.
Search for "0-90db/60/30 button adjustable / step attenuator"
Regards,
Martin
--
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Push buttons get pretty cranky over time and use.? Real toggle switches are more reliable.?
Dave - W?LEV
On Wed, Jul 10, 2024 at 8:52?PM Martin via <martin_ehrenfried= [email protected]> wrote: On Wed, Jul 10, 2024 at 04:27 PM, Dean Kiefer wrote:
Pacific Antenna has a 41db in 1 db steps kit
Hi Dean,
I think it's fine for HF use, they claim up to 200MHz, but I'd suggest 30MHz is more reasonable before the performance tails off.
Ideally, it needs to be in a metal box, otherwise you will get signals leaking in (and out), and I suspect it wouldn't achieve 40dB isolation whilst in a plastic case.
You can obtain push button binary value step attenuators, in various power ratings and step sizes, rated up to a few GHz from AliExpress, with prices starting at around $25 USD for a 2w 0-30dB version.
Search for "0-90db/60/30 button adjustable / step attenuator"
Regards,
Martin
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On Wed, Jul 10, 2024 at 04:27 PM, Dean Kiefer wrote:
Pacific Antenna has a 41db in 1 db steps kit
Hi Dean, I think it's fine for HF use, they claim up to 200MHz, but I'd suggest 30MHz is more reasonable before the performance tails off. Ideally, it needs to be in a metal box, otherwise you will get signals leaking in (and out), and I suspect it wouldn't achieve 40dB isolation whilst in a plastic case. You can obtain push button binary value step attenuators, in various power ratings and step sizes, rated up to a few GHz from AliExpress, with prices starting at around $25 USD for a 2w 0-30dB version.  Search for "0-90db/60/30 button adjustable / step attenuator" Regards, Martin
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Pacific Antenna has a 41db in 1 db steps kit for $25. It's rated at 5w continuous and 10 watt intermittent signals. You can use free software from Thingverse to 3d print a case. It took me less than two hours to build the kit.
Dean Kiefer
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Gregg, if you would, could you post a link to that video please??
I just searched for 'AG0AG' and usually the content provider shows
up but I am getting nothing.? I would appreciate it!
Thanks,
Bob Ruth
On 7/7/24 12:16, Gregg Lebovitz (kd1mu)
wrote:
toggle quoted message
Show quoted text
I
am following a video on YouTube by AG0AG to build a tap
attenuator out of 2 watt resistors. As it is a tap, it gets 60DB
attenuation while running the bulk of the signal to a dummy
load. I have a 100 watt and a 1500 watt dummy load.
?
All
the parts came from Ali and totaled $12.
?
I
will construct it next week, but I am expecting good results. I
also bought a ceramic 50 ohm attenuator and a heat sink to mount
it on. This is to attenuate the signal from the rig to the amp.
It seems to do the job.
?
The
alternative was $90 for a 100 watt attenuator and $15 for a 10
watt one.
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GR connectors have been obsolete for years, better to stick with things like the APC7 etx.
73
Jeff G8HUL
toggle quoted message
Show quoted text
-----Original Message----- From: [email protected] < [email protected]> On Behalf Of Zack Widup Sent: 08 July 2024 15:02 To: [email protected]Subject: Re: [tinysa] Attenuators How many attentaturs are available with GR connectors? It looks like GR connectors are only rated to 9 GHz. I do a lot of work up to 18 GHz and need attenuators rated to 18 GHz. Also, are there GR to SMA adaptors? All my microwave equipment has SMA or 3.5 mm connectors. Zack W9SZ On Thu, Jun 13, 2024 at 11:40?AM Martin via groups.io <> <martin_ehrenfried@... <mailto: [email protected]> > wrote: On Thu, Jun 13, 2024 at 03:23 PM, Prawlin wrote: Aha, but is that the male centre pin end, or the male thread end? This gender description always gets me! Better stick with hermaphroditic connectors, such as the General Radio Type 874, but they are a bit bulky. Otherwise, this may (genuinely) help Regards, Martin <> Virus-free.www.avast.com <>
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I'm surprised GR connectors are rated to 9 GHz!? The geometry is large and the insulator is clear plastic of some sort.? They are just physically too large to serve 9 GHz.?
Yes, I have seen a few GR to SMA / BNC / SO-239 / whatever.? These days they are hard to find.? Here are a few sources I found with a quick Startpage www search:
????
????
????
Dave - W?LEV
How many attentaturs are available with GR connectors? It looks like GR connectors are only rated to 9 GHz. I do a lot of work up to 18 GHz and need attenuators rated to 18 GHz. Also, are there GR to SMA adaptors? All my microwave equipment has SMA or 3.5 mm connectors.
Zack W9SZ
On Thu, Jun 13, 2024 at 11:40?AM Martin via <martin_ehrenfried= [email protected]> wrote: On Thu, Jun 13, 2024 at 03:23 PM, Prawlin wrote:
Aha, but is that the male centre pin end, or the male thread end? This gender description always gets me!
Better stick with hermaphroditic connectors, such as the General Radio Type 874, but they are a bit bulky.
Otherwise, this may (genuinely) help
Regards,
Martin
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