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Re: Attenuator needed for my purpose?
No, it does not specifically address ESD.? However, I will be effective for low level ESD.? The best insurance against ESD if care......CARE......? Further, when working with this sort of equipment, its always a good idea to touch the chassis before anything else like connecting cables.? That way you and the unit will be at the same potential. Dave - W?LEV On Tue, Jun 4, 2024 at 11:00?PM Robin via <dulca=[email protected]> wrote:
-- Dave - W?LEV |
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Re: Attenuator needed for my purpose?
On Tue, Jun 4, 2024 at 10:10 PM, Martin wrote:
That's the dilemma with a lot of kit these days, it was a lot easier back in the day when a $50 attenuator could help save a $50K SA, and a fair amount of embarrassment from the operator's perspective, especially when paying the repair bill. It was also when such expensive instruments were only available to folks who had some training prior to being let loose on one. Hi Martin, I know that dilema all too well. Gladly I was always so scared that I would damage this piece of equipment that cost more than twice my yearly wages that I would always start with twice the attenuation that back of a cigarette packet maths predicted that I would need. My advice to anyone starting out would be to invest in a set of attenuators so that you can stack any attenuator value needed from 1dB to at least 100dB in 1dB steps. This can easily and faily cheaply done with just 8 attenuators which would give you 112dB of attenuation in 1dB steps. Just a simple set of 1, 2, 3, 6, 10, 20, 30 and 40dB attenuators will provide you with 1dB-112dB of attenuation in 1dB steps. A small investment that WILL save you time and time again from accidental misscalculations or the occaisional brain fart. Forgive my spelling as sent from my phone. Paul |
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Re: Attenuator needed for my purpose?
¿ªÔÆÌåÓýDave,Odds are I misunderstood what you wrote (said)? Here's the link/URL for the MiniCircuits model VLM-33W-2w-S%2B spec sheet: In part it states: Mini-Circuits¡¯ VLM-33-2W+ is a coaxial RF limiter ideal for protecting sensitive receiver circuitry from high-power signals, while allowing low-scattered signals to be receivedNo where in - on the site do I see a (any) info - data about "ESD" charge, discharge, etc.? Did I miss something? Remain WELL & be SAFE! Robin - - - - - - - - - - - - - - - - - - - - - - - - - - - - - On 6/4/2024 10:05 AM, W0LEV wrote:
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Re: Attenuator needed for my purpose?
Yes, addition of the limiter from MCL will add an additional 1.4-inches to your connector (I just measured mine).? But it's good insurance. I don't know where Eric placed the inline attenuators in the functional flow.? But certainly far enough "inside" that if fields are conducted inside the assembly, damage is likely to occur.? LECTRONICS:? I designed their first UHF wireless mic.? The main requirement was that the standard 9 volt "transistor" battery last a full movie shoot, that being 8-hours.? I was reminded that these microphones are tucked in some unmentionable places on actors where the "sun don't shine".? Replacing batteries during a shoot can cost quite a bit of time (translated: $$$$).? I struggled a bit, but managed by using a parametric trippler in the driver stage to the output.? I had experience with that technology when I designed and built my home brew 1296 MHz transverter which was published in the 1985 ARRL Handbook for the Radio Amateur.? I also designed the front end of the complementary UHF receiver.? Oh, yes, and I was also responsible for hiring a couple of additional engineers and one tech.? Our main test of any of our top end systems was to take a trip to Sandia Peak on the east side of Albuquerque.? If you're not aware, that is officially the third most RF polluted peak in the lower 48.? Mt. Wilson in S. Cal. is #1 and Mt. Washington back east is #2.? None of our competitors' wireless mics would pass the "Sandia Peak Test".? Our top end products passed with flying colors.? The secret was the 6-cavity helical filters in the front ends.? For marketing and pizzazz (maybe a parallel would be "Monster Cable".....snake oil), the cap to the helicals was a highly polished piece of aluminum with "ULTRA LINEAR" engraved in it.? Only our top end products had them. When Lectronics first hung out their shingle, their sole product was a "talking whiteboard".? It would read and enunciate what was written on the board to a large crowd (PA style).? Well, that didn't go over too well.? So they decided to get into the wireless mic business.? Pricing was set rather low but truly reflected the design, sourcing, building, marketing, and operating costs.?? Original pricing of our offerings was so low that it was viewed as "junk", far lower than Nady "lack of quality"!? So we got real with pricing and gave ourselves a horrendous profit margin.? That and the quality got us noticed in the industry. ?
We had our own assembly line and eventually installed our own pick-and-place facility.? The rest is history. Gosh, it's been some 35+ years since I left Lectronics.? We left Albuquerque in 1995 for N. Colorado where we presently reside about 50-miles north of Denver and about 50-miles south of Cheyenne, Wy. in the country for radio astronomy and amateur radio.? I'm retired and enjoying every moment home brewing and helping others mostly online and with the STEM program at the local high school. Dave - W?LEV On Tue, Jun 4, 2024 at 9:08?PM Derek H via <hansonsoundcorp=[email protected]> wrote: While it is a little painful to add on another $100 worth of parts to a device that only cost me $150 maybe that's the price of reliability and longevity for this thing.. The other bummer about this is adding a two inch metal pry-bar to the SMA input which I'm sure is just a board mounted connector.. That might kill the unit faster than RF overloads.? -- Dave - W?LEV |
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Re: Attenuator needed for my purpose?
On Tue, Jun 4, 2024 at 07:11 PM, Bruce Hawkins wrote:
That's pretty pricey for our units... That's the dilemma with a lot of kit these days, it was a lot easier back in the day when a $50 attenuator could help save a $50K SA, and a fair amount of embarrassment from the operator's perspective, especially when paying the repair bill. It was also when such expensive instruments were only available to folks who had some training prior to being let loose on one. This has now changed, and hobbyists tend to learn just by using one, which means that it's much easier to make a mistake, and why I think it's still a good habit to learn. Regards, Martin |
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Re: Attenuator needed for my purpose?
While it is a little painful to add on another $100 worth of parts to a device that only cost me $150 maybe that's the price of reliability and longevity for this thing.. The other bummer about this is adding a two inch metal pry-bar to the SMA input which I'm sure is just a board mounted connector.. That might kill the unit faster than RF overloads.?
Dave, you worked for Lectrosonics? Which products did you work on?? They're very much alive and well and has been the first choice for professional sound mixers in my field for a long time. That said I think they're struggling a bit to transition to digital wireless. Shure, Zaxcom, and now Sound Devices are all trying to give them a run for their money. If you're bored check out their current website they have quite a nice product line. Back to the topic... So if you're using an inline attenuator do you set that value in the menu somewhere so that your readings stay true? Also, why is the built-in attenuation of the tinySA inadequate? Is that only a software adjustment or something? |
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Re: Attenuator needed for my purpose?
Well, yes, there is something more cost effective: buy yourself a low-capacitance snubber diode (not a TVSS, Transorb, or Zener - far too much capacitance!!!).? They're made for the purpose and likely inside the MiniCircuit unit.? Then build it into a conector(s) of your choice. Dave - W?LEV ? On Tue, Jun 4, 2024 at 6:41?PM Richard B. Emerson via <pavilion=[email protected]> wrote: Er, nice thought but not particularly cost effective at about 50% the cost of an Ultra (or 2/3 of an Ultra via DigiKey - are they nuts??). Surely there's something a little more cost effective.? -- Dave - W?LEV |
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Re: Attenuator needed for my purpose?
Bruce Hawkins
My comment are regarding the below attached... The, MiniCurcuits: the VLM-33W-2W-S+, is ~$97 That's pretty pricey for our units... ___________________________________________________________ https://www.minicircuits.com/WebStore/dashboard.html?model=VLM-33W-2W-S%2B That should be installed directly and permanently on the input of the TinySA. Since you do this professionally, I'd strongly advise you permanently (in addition to any attenuators) attach a limiter to snub any ESD. The unit is quite sensitive to damage from exposure to ESD discharges, especially with the supplied antenna attached directly. I'd recommend a small unit from MiniCurcuits: the VLM-33W-2W-S+ https://www.minicircuits.com/WebStore/dashboard.html?model=VLM-33W-2W-S%2B That should be installed directly and permanently on the input of the TinySA. Bruce Hawkins AC6DN On Tuesday, June 4, 2024 at 10:05:25 AM CDT, W0LEV <davearea51a@...> wrote: QUOTE:? I'm a sound engineer not an RF engineer let's just start there.. Wondering if I should be always using an attenuator on the input of my TinySA Ultra to protect it or only if I observe a signal that's nearing 0dB? Will the TinySA warn you somehow of an overload? The TinySA does not issue any warning of overload.? If the input exceeds nominally -25 dBm, you may notice additional internally generated spurs that are not part of the measurement.? These become more and stronger as the input level(s) is exceeded.? Eventually, the unit will cease functioning and considered "bricked". ? A little background.. I'm using the TinySA to scan mostly VHF and UHF but sometimes 2.4GHz and 5GHz to help coordinate and troubleshoot our wireless mics and wireless video equipment. Generally the power levels we deal with are well under 1W but some video transmitters go higher... I am often wearing an active wireless mic myself (100mW transmitter) for coms purposes. Does operating the TinySA very close to the a transmitter like that run the risk of overloading or damaging it? Yes, at 1-watt, +30 dBm, or more the unit will be damaged.? Can I connect the output of a transmitter directly to the tinySA with a piece of coax without an attenuator or is this bad for both devices? NO!? Do not connect anything much more than 0 dBm, 1-mW, directly to the TinySA.? A bit more, only "a bit" may work OK, but will display internally generated spurs on the display.? Sorry for the basic questions. Just looking for some best practice basics. If I'm just going to buy one attenuator for this purpose what's a good value? 10/20/30 dB? Since you are involved professionally with audio, you are likely familiar with the dB.? Dealing with RF energy, we usually refer to power in dBm, dB referenced to 1-mW in a non-reactive 50-ohm system.? Every 10 dB of attenuation yields 0.10 times the input power.? To obtain a "safe" level to input to the TinySA, you need to reduce your 1-watt transmitters to 0 dBm.? That would require a 30-dB attenuator that is able to handle 1-watt.? With that, you could safely connect your 1-watt transmitters directly to the TinySA.? However, at that level, you will experience internally generated spurs.? You would prefer an additional 25 to 30 dB of attenuation to view a faithful rendition of your signal without additional internally generated spurs.? Since you do this professionally, I'd strongly advise you permanently (in addition to any attenuators) attach a limiter to snub any ESD.? The unit is quite sensitive to damage from exposure to ESD discharges, especially with the supplied antenna attached directly.? I'd recommend a small unit from MiniCurcuits:? the VLM-33W-2W-S+ ???? That should be installed directly and permanently on the input of the TinySA. Long ago and far away, I used to be one of the design engineers for a wireless mic. company, Lectronics.? I don't believe they are around anymore, but some good experiences with wireless mics. Dave - W?LEV ??? On Tue, Jun 4, 2024 at 2:38?PM Derek H via <hansonsoundcorp=[email protected]> wrote: Hello, -- Dave - W?LEV |
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Re: Attenuator needed for my purpose?
The 3 dB attenuator likely has a shunt resistive element at the input.? Yes, this will help, but is not enough if the external antenna comes in contact with a "charged" surface, especially during dry winter days.? The MiniCircuit unit I referred to
(they're only $64)
is pretty much a "standard" for protecting the input port of any SA (or VNA) against ESD and other invasive high-power sources.? I would not rely on the 3 dB pad.? Dave - W?LEV On Tue, Jun 4, 2024 at 3:48?PM Richard B. Emerson via <pavilion=[email protected]> wrote: Please explain the use of a simple attenuator for ESD protection.? -- Dave - W?LEV |
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Re: Attenuator needed for my purpose?
Please explain the use of a simple attenuator for ESD protection.?
It?was my understanding something like? a simple 2 or 3 db attenuator on the input side of an Ultra was sufficient for dealing with inadvertent ESD snaps. At the moment, my Ultra is reporting what appears around 319.5 MHz, as received by the simple whip antenna. The presentation is in line with my expectations. I added a simple 3 db attenuator between the antenna and Ultra "just in case".? Question: is the 3 db pad doing anything as far as ESD protection? If not, what should I use?? 73 Rick KC3DOO |
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Re: TinySA Ultra generates signals while sweeping
Bruce Hawkins
Regarding other interesting things one could measured/ listen to with our devices... Before the big earthquake in 1989 in the bay area/ Santa Cruz (1989 Loma Prieta earthquake), there was a big radio noises heard coming from Earth. It was theorized that it was the piezoelectric effect of the ground getting squeezed. I can't find the original story but this is what I could find for any one interested: https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2012GL052123 Bruce Hawkins AC6DN On Tuesday, June 4, 2024 at 08:19:41 AM CDT, Matt Harris <kd4pbs@...> wrote: Apparently the subliminal sarcasm font I used did not make it through the Groups.io interface. ;) |
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Re: Attenuator needed for my purpose?
QUOTE:?
I'm a sound engineer not an RF engineer let's just start there..
Wondering if I should be always using an attenuator on the input of my
TinySA Ultra to protect it or only if I observe a signal that's nearing
0dB? Will the TinySA warn you somehow of an overload? The TinySA does not issue any warning of overload.? If the input exceeds nominally -25 dBm, you may notice additional internally generated spurs that are not part of the measurement.? These become more and stronger as the input level(s) is exceeded.? Eventually, the unit will cease functioning and considered "bricked". ? A little
background.. I'm using the TinySA to scan mostly VHF and UHF but
sometimes 2.4GHz and 5GHz to help coordinate and troubleshoot our
wireless mics and wireless video equipment. Generally the power levels
we deal with are well under 1W but some video transmitters go higher... I
am often wearing an active wireless mic myself (100mW transmitter) for
coms purposes. Does operating the TinySA very close to the a transmitter
like that run the risk of overloading or damaging it? Yes, at 1-watt, +30 dBm, or more the unit will be damaged.? Can I
connect the output of a transmitter directly to the tinySA with a piece
of coax without an attenuator or is this bad for both devices? NO!? Do not connect anything much more than 0 dBm, 1-mW, directly to the TinySA.? A bit more, only "a bit" may work OK, but will display internally generated spurs on the display.? Sorry for the basic questions. Just looking for some best practice basics. If I'm just going to buy one attenuator for this purpose what's a good value? 10/20/30 dB? Since you are involved professionally with audio, you are likely familiar with the dB.? Dealing with RF energy, we usually refer to power in dBm, dB referenced to 1-mW in a non-reactive 50-ohm system.? Every 10 dB of attenuation yields 0.10 times the input power.? To obtain a "safe" level to input to the TinySA, you need to reduce your 1-watt transmitters to 0 dBm.? That would require a 30-dB attenuator that is able to handle 1-watt.? With that, you could safely connect your 1-watt transmitters directly to the TinySA.? However, at that level, you will experience internally generated spurs.? You would prefer an additional 25 to 30 dB of attenuation to view a faithful rendition of your signal without additional internally generated spurs.? Since you do this professionally, I'd strongly advise you permanently (in addition to any attenuators) attach a limiter to snub any ESD.? The unit is quite sensitive to damage from exposure to ESD discharges, especially with the supplied antenna attached directly.? I'd recommend a small unit from MiniCurcuits:? the VLM-33W-2W-S+ ???? That should be installed directly and permanently on the input of the TinySA. Long ago and far away, I used to be one of the design engineers for a wireless mic. company, Lectronics.? I don't believe they are around anymore, but some good experiences with wireless mics. Dave - W?LEV ??? On Tue, Jun 4, 2024 at 2:38?PM Derek H via <hansonsoundcorp=[email protected]> wrote: Hello, -- Dave - W?LEV |
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Re: Attenuator needed for my purpose?
See below
toggle quoted message
Show quoted text
On Tue, Jun 4, 2024 at 07:38 AM, Derek H wrote: I'm a sound engineer not an RF engineer let's just start there.. Wondering if I should be always using an attenuator on the input of my TinySA Ultra to protect it or only if I observe a signal that's nearing 0dB?Better always have 10 or 20dB attenuator connected to the input Will the TinySA warn you somehow of an overload?Yes, but the damage could already have happened. A little background.. I'm using the TinySA to scan mostly VHF and UHF but sometimes 2.4GHz and 5GHz to help coordinate and troubleshoot our wireless mics and wireless video equipment. Generally the power levels we deal with are well under 1W but some video transmitters go higher... I am often wearing an active wireless mic myself (100mW transmitter) for coms purposes. Does operating the TinySA very close to the a transmitter like that run the risk of overloading or damaging it?Yes, but with a 20 dB attenuator connected between an antenna and the tinySA you will be mostly safe, Can I connect the output of a transmitter directly to the tinySA with a piece of coax without an attenuator or is this bad for both devices?Yes if the antenna's make direct contact or you connect the transmitter directly to the tinySA you can easily destroy the tinySA.? With transmitters operating at 100mW and a 20dB attenuator connected to the input of the tinySA you are perfectly safe Sorry for the basic questions. Just looking for some best practice basics. If I'm just going to buy one attenuator for this purpose what's a good value? 10/20/30 d20dB, you can buy any cheap 2 W attenuator ? -- Designer of the tinySA For more info go to https://tinysa.org/wiki/ |
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Re: Attenuator needed for my purpose?
Using the antenna in a low power environment (mW), 10db is good. Use the device's LNA. Very helpful... For a direct connect you want to measure---for cleanest signals---something around a 10 MILLIONTH of a watt! If your mic puts out 100 mW, that would require 60db of attenuation?
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Re: Attenuator needed for my purpose?
Personally I always keep an attenuator connected, that's how I was taught, and it has saved me from mishaps on many occasions throughout my working career.
You don't often need the full sensitivity of a SA, so I tend to use a 20dB attenuator, but in your case where you are dealing with relatively low power devices I think a 10dB would be a reasonable compromise. Regards, Martin |
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Re: TinySA Ultra generates signals while sweeping
Yes, indeed.? You just visited the photo-electric effect.? The light from the light saber (flashlight) freed a few electrons from the electrodes inside the NE-2.? Uncontrolled conduction occurs (no resistor) and the little glass bottle of neon explodes.? Neat "experiment"! Dave - W?LEV On Tue, Jun 4, 2024 at 2:31?AM Mike C. via <mg=[email protected]> wrote:
-- Dave - W?LEV |
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Attenuator needed for my purpose?
Hello,
I'm a sound engineer not an RF engineer let's just start there.. Wondering if I should be always using an attenuator on the input of my TinySA Ultra to protect it or only if I observe a signal that's nearing 0dB? Will the TinySA warn you somehow of an overload? A little background.. I'm using the TinySA to scan mostly VHF and UHF but sometimes 2.4GHz and 5GHz to help coordinate and troubleshoot our wireless mics and wireless video equipment. Generally the power levels we deal with are well under 1W but some video transmitters go higher... I am often wearing an active wireless mic myself (100mW transmitter) for coms purposes. Does operating the TinySA very close to the a transmitter like that run the risk of overloading or damaging it? Can I connect the output of a transmitter directly to the tinySA with a piece of coax without an attenuator or is this bad for both devices? Sorry for the basic questions. Just looking for some best practice basics. If I'm just going to buy one attenuator for this purpose what's a good value? 10/20/30 dB? |
Derek H
Richard B. Emerson
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