Locked
Re: Questions about ferrites
Amadon is the worst place to go, their prices are very high, they have a high minimum order and their shipping cost are outrages.
?
The link I gave for Kit-Parts is the best place to go. All of his Ferrite is from Fair-Rite. He has no minimum, his ferrite prices are lower than Amadon's and his shipping cost are reasonable.
?
Everett N4CY
In a message dated 1/13/2022 2:34:44 PM Central Standard Time, richard@... writes:
?
Amidon re-sells Fair-Rite cores.? It is an "unauthorized" distributor.? They copy the material designation (EG, 31) but have their own numbering system for the shape.
However, Fair-Rite's material designations are not applicable to other manufacturers.
Fair-Rite DOES sell toroids in 31 material, but in that material they
are called "Round Cable EMI Suppression Cores".
Yes, this is confusing.? But it is what it is.
Regarding pricing:? the best pricing is from Fair-Rite authorized distributors, which sell to businesses.? The "hobby" sellers like Amidon are MUCH more expensive.
?
On 2022-01-13 11:16, Tomasz Lemiech wrote:
?
Hi,
?
You guys often use terms like FTxxx-yy or BNxxx-yy to refer to various ferrite products - like "use x turns on a FT240-31 for this application". By that, do you have any particular manufacturer / brand / product number in mind? Or do you mean that any product of 2.4" diameter made of 31 material will do, even when it's a no-name brand?
?
I guess this scheme might have come from Amidon's product lineup, which seems to use these markings (). That would make sense. But then I see things like which is allegedly made by Fair-Rite. However "FT240-31" string is nowhere to be found on their webpage - they have their own numbering scheme. What's more, according to they don't make toroids out of 31.
?
Another thing is mix type numbers. For some reason, Amidon's numbers seem to coincide with Fair-Rite's. Is there any standard or industrial norm that these numbers come from? Is it safe to assume that, for example, a toroid made of 31 is mostly the same thing performance-wise, regardless of the brand stamped on the product?
?
Apparently Amidon has FT240-31 in their product line () but there is no specs for this mix on their page (). But they are currently updating it, so fingers crossed! ;-)
?
Have you encountered any gotchas during your prior purchases? Like two toroids with the same FT or BN number from two different brands, having completely different characteristics?
?
Regards,
--
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Locked
Re: Questions about ferrites
Amidon re-sells Fair-Rite cores.? It is an "unauthorized" distributor.? They copy the material designation (EG, 31) but have their own numbering system for the shape.
However, Fair-Rite's material designations are not applicable to other manufacturers.
Fair-Rite DOES sell toroids in 31 material, but in that material they
are called "Round Cable EMI Suppression Cores".
Yes, this is confusing.? But it is what it is.
Regarding pricing:? the best pricing is from Fair-Rite authorized distributors, which sell to businesses.? The "hobby" sellers like Amidon are MUCH more expensive.
toggle quoted message
Show quoted text
On 2022-01-13 11:16, Tomasz Lemiech wrote:
?
Hi,
?
You guys often use terms like FTxxx-yy or BNxxx-yy to refer to various ferrite products - like "use x turns on a FT240-31 for this application". By that, do you have any particular manufacturer / brand / product number in mind? Or do you mean that any product of 2.4" diameter made of 31 material will do, even when it's a no-name brand?
?
I guess this scheme might have come from Amidon's product lineup, which seems to use these markings (). That would make sense. But then I see things like which is allegedly made by Fair-Rite. However "FT240-31" string is nowhere to be found on their webpage - they have their own numbering scheme. What's more, according to they don't make toroids out of 31.
?
Another thing is mix type numbers. For some reason, Amidon's numbers seem to coincide with Fair-Rite's. Is there any standard or industrial norm that these numbers come from? Is it safe to assume that, for example, a toroid made of 31 is mostly the same thing performance-wise, regardless of the brand stamped on the product?
?
Apparently Amidon has FT240-31 in their product line () but there is no specs for this mix on their page (). But they are currently updating it, so fingers crossed! ;-)
?
Have you encountered any gotchas during your prior purchases? Like two toroids with the same FT or BN number from two different brands, having completely different characteristics?
?
Regards,
--
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Locked
Re: Questions about ferrites
The best place to go for small orders is
?
Everett N4CY
In a message dated 1/13/2022 2:03:09 PM Central Standard Time, davearea51a@... writes:
?
Do not use the "no-name" ferrites, especially from China.? They typically are not mixed well before firing, are not properly fired, many are cracked, and they are not deburred.? Worst of all, they likely will not conform to the published specifications for any given material as a result of these shortcomings.? Stick with Amidon, FairRite, TDK, and MicroMetals (there may be others, but these are the suppliers I've used over the decades).?
?
An excellent and economic source of ferrites (and many other "goodies") is the following:
?
????
?
He carries all the "good" brands and the cost is considerably less than Amidon and others.? He is an excellent supplier and quite prompt - in the SLC area.? The ferrites are toward the bottom of his www page.
?
Dave - W?LEV?
?
On Thu, Jan 13, 2022 at 7:17 PM Tomasz Lemiech < szpajder@...> wrote:
?
Hi,
?
You guys often use terms like FTxxx-yy or BNxxx-yy to refer to various ferrite products - like "use x turns on a FT240-31 for this application". By that, do you have any particular manufacturer / brand / product number in mind? Or do you mean that any product of 2.4" diameter made of 31 material will do, even when it's a no-name brand?
?
I guess this scheme might have come from Amidon's product lineup, which seems to use these markings (). That would make sense. But then I see things like which is allegedly made by Fair-Rite. However "FT240-31" string is nowhere to be found on their webpage - they have their own numbering scheme. What's more, according to they don't make toroids out of 31.
?
Another thing is mix type numbers. For some reason, Amidon's numbers seem to coincide with Fair-Rite's. Is there any standard or industrial norm that these numbers come from? Is it safe to assume that, for example, a toroid made of 31 is mostly the same thing performance-wise, regardless of the brand stamped on the product?
?
Apparently Amidon has FT240-31 in their product line () but there is no specs for this mix on their page (). But they are currently updating it, so fingers crossed! ;-)
?
Have you encountered any gotchas during your prior purchases? Like two toroids with the same FT or BN number from two different brands, having completely different characteristics?
?
Regards,
--
?
?
--
Dave - W?LEV
Just Let Darwin Work
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Locked
Re: Questions about ferrites
Do not use the "no-name" ferrites, especially from China.? They typically are not mixed well before firing, are not properly fired, many are cracked, and they are not deburred.? Worst of all, they likely will not conform to the published specifications for any given material as a result of these shortcomings.? Stick with Amidon, FairRite, TDK, and MicroMetals (there may be others, but these are the suppliers I've used over the decades).?
An excellent and economic source of ferrites (and many other "goodies") is the following:
????
He carries all the "good" brands and the cost is considerably less than Amidon and others.? He is an excellent supplier and quite prompt - in the SLC area.? The ferrites are toward the bottom of his www page.
Dave - W?LEV?
On Thu, Jan 13, 2022 at 7:17 PM Tomasz Lemiech < szpajder@...> wrote:
Hi,
You guys often use terms like FTxxx-yy or BNxxx-yy to refer to various ferrite products - like "use x turns on a FT240-31 for this application". By that, do you have any particular manufacturer / brand / product number in mind? Or do you mean that any product of 2.4" diameter made of 31 material will do, even when it's a no-name brand?
I guess this scheme might have come from Amidon's product lineup, which seems to use these markings (). That would make sense. But then I see things like which is allegedly made by Fair-Rite. However "FT240-31" string is nowhere to be found on their webpage - they have their own numbering scheme. What's more, according to they don't make toroids out of 31.
Another thing is mix type numbers. For some reason, Amidon's numbers seem to coincide with Fair-Rite's. Is there any standard or industrial norm that these numbers come from? Is it safe to assume that, for example, a toroid made of 31 is mostly the same thing performance-wise, regardless of the brand stamped on the product?
Apparently Amidon has FT240-31 in their product line () but there is no specs for this mix on their page (). But they are currently updating it, so fingers crossed! ;-)
Have you encountered any gotchas during your prior purchases? Like two toroids with the same FT or BN number from two different brands, having completely different characteristics?
Regards,
--
-- Dave - W?LEV
Just Let Darwin Work
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Locked
Re: LZ1AQ choke and feeder length questions please.
Cable protection or even burying in gnd via suitable conduit is good..stops the bloody foxes here in London..( fcukers are everywhere!)
Saying on gnd or below because qro transmissions will ingress said cable if close/ up high/ or cable length just happens to be 1/4w or multiples of..
Ask how i know!!
I ran my rx loop cables fence height at first..easy..now in/ on gnd. ( not easy) MASSIVE difference in cm pickup and opps cables re radiating rf.( causing all sorts of grief.) lesson learned.
Cable protection sleeving comes in 25m rolls, cheap, easy to use.( corrigated slit stuff…spelt that wrong.) used in automotive industry mainly on hgv’s ( trucks) really good strong stuff, wears out metal if rubbing it. Gives the foxes a good run for their money! Not lost another cable..
Why the hell do foxes want to eat cables and antenna support ropes???
Simon g0zen
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Locked
Questions about ferrites
Hi,
You guys often use terms like FTxxx-yy or BNxxx-yy to refer to various ferrite products - like "use x turns on a FT240-31 for this application". By that, do you have any particular manufacturer / brand / product number in mind? Or do you mean that any product of 2.4" diameter made of 31 material will do, even when it's a no-name brand?
I guess this scheme might have come from Amidon's product lineup, which seems to use these markings (). That would make sense. But then I see things like which is allegedly made by Fair-Rite. However "FT240-31" string is nowhere to be found on their webpage - they have their own numbering scheme. What's more, according to they don't make toroids out of 31.
Another thing is mix type numbers. For some reason, Amidon's numbers seem to coincide with Fair-Rite's. Is there any standard or industrial norm that these numbers come from? Is it safe to assume that, for example, a toroid made of 31 is mostly the same thing performance-wise, regardless of the brand stamped on the product?
Apparently Amidon has FT240-31 in their product line () but there is no specs for this mix on their page (). But they are currently updating it, so fingers crossed! ;-)
Have you encountered any gotchas during your prior purchases? Like two toroids with the same FT or BN number from two different brands, having completely different characteristics?
Regards,
--
|
On Wed, Jan 12, 2022 at 01:40 PM, чавдар левков wrote:
?
? I think that there is misunderstanding :???? -30 dBm is the maximal signal level at the SDR input when 100 w TRX at full power is used.??? 100 W = +50 dBm so the insulation is? 80 dB.? This is at the highest frequency. For example at 1.8 MHz the insulation is above 90 dB. ?I will change the documentation to make that clear.
Thank you for the clarification on TX-SDR isolation. It would have been nice if you has a hybrid splitter (for receive) in the design instead of using a T connector and a 3 .7 db pad on the receive (for impedance isolation). MFJ uses one in their MFJ-1708BSDR and it provides isolation between the SDR and the transceiver during receive operation.? Some comments on the use of a T-connector during receive. A T-connector is a poor way to parallel two receiver inputs together. Doing it this way can lead to a number of problems including:
- The input impedances of the two receivers are rarely 50 ohms and the signal will not be split equally between the receivers. If they are both 50 ohms there will be a 3 dB drop in signal power into each. If one is 50 ohms and the other is less than 50 ohms the lower one will get more power and the 50 ohm input receiver will have much more than 3 dB loss.? This is? particularly evident when the two radios are on different bands and the front-end filters are not operating in their passband.
- Even when both receivers are 50 ohm input impedance they are 25 ohms in parallel and this will result in a mismatch with the circuit or antenna providing the receive input signal and result in less than maximum signal power transfer.
- Spurious signals present on the antenna input port of one receiver (like local oscillator feedthrough) will directly couple into the other receiver and degrade it's performance.
- If a bias-t port is used on the SDR and the bias T is accidentally enabled approximately 5 volts will be injected into the front end of an expensive ham transceiver. This can cause considerable damage if it does not have DC blocking at the antenna input.?
The best approach is to use an RF splitter to split the signal between the receivers. This is a passive device which has about 3.8 dB of power loss and at least 20 dB of isolation between ports. This loss is not significant on HF (below 15 MHz.) because the signal and noise are both lowered by the same amount so the SNR stays the same. Roger
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Locked
Re: LZ1AQ choke and feeder length questions please.
From my experience as a former cellphone base station engineer in
Southern England, I found that the most common culprits in rural
sites were small woodmice. They even managed to get inside the
cabins occasionally and could be found happily nesting in the
cable trays.
Ian Brooks, Verwood, Dorset, UK.
On 13/01/2022 15:51, Martin via
groups.io wrote:
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Show quoted text
On Thu, Jan 13, 2022 at 03:07 PM, Simon wrote:
On the ground would be better..
Maybe, but in woodland it's likely to get chewed by various
animals, unless you run it in some hose pipe or similar
protection. Even if it is a few feet up in the sky, squirrels will
be tempted to have a go at it.
Regards,
Martin
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Locked
Re: LZ1AQ choke and feeder length questions please.
On Thu, Jan 13, 2022 at 03:07 PM, Simon wrote:
On the ground would be better..
Maybe, but in woodland it's likely to get chewed by various animals, unless you run it in some hose pipe or similar protection. Even if it is a few feet up in the sky, squirrels will be tempted to have a go at it. Regards, Martin
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Locked
Re: LZ1AQ choke and feeder length questions please.
On the ground would be better..
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Locked
Re: LZ1AQ choke and feeder length questions please.
Best person to ask is LZ1AQ. Great guy and always responds. I have about a 50 foot run and it works fine. I have no?choke on it.?
Mike AB4KJ
On Thu, Jan 13, 2022 at 6:12 AM Chris Wilson < chris@...> wrote: 13 January 2022
I bought an LZ1AQ? active antenna amplifier to try. The performance of my Wellbrook wide aperture loop has been excellent since moving it further from the house, so I would like to try a loop as far from my house and other prorties as possible. What is the maximum realistic length of CAT5e cable I can run please? It will be suspended above head height off trees in a big wood. As a maybe very nueve aside questiomn, can such a signal be "boosted
As for a choke or pair of chokes for the CAT5e, my main interests are the amateur bands at LF, MF and 160 meters. What would people recommend as a ferrite material to use?
Many thanks
--
Best regards,
?Chris? ? ? ? ? ? ? ? ? ? ? ? ? ? mailto:chris@...
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Re: LZ1AQ choke and feeder length questions please.
On Thu, Jan 13, 2022 at 12:11 PM, Chris Wilson wrote:
What is the maximum realistic length of CAT5e cable I can run please? It will be suspended above head height off trees in a big wood. As a maybe very nueve aside questiomn, can such a signal be "boosted
As for a choke or pair of chokes for the CAT5e, my main interests are the amateur bands at LF, MF and 160 meters. What would people recommend as a ferrite material to use?
A 30m (100ft) length of Cat 5 has typically 3 dB of attenuation at 30MHz, 2dB at 10MHz and <1dB at 1MHz. If your receiver noise floor rises by >6dB when the antenna is connected, you won't have a problem. 20 turns on an FT240-31 core for 160m & 80m. Try type 77 material for lower frequencies, but you would need about 40 turns for the 300-500KHz NDB band which is not really practical. Regards, Martin
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Locked
LZ1AQ choke and feeder length questions please.
13 January 2022
I bought an LZ1AQ active antenna amplifier to try. The performance of my Wellbrook wide aperture loop has been excellent since moving it further from the house, so I would like to try a loop as far from my house and other prorties as possible. What is the maximum realistic length of CAT5e cable I can run please? It will be suspended above head height off trees in a big wood. As a maybe very nueve aside questiomn, can such a signal be "boosted
As for a choke or pair of chokes for the CAT5e, my main interests are the amateur bands at LF, MF and 160 meters. What would people recommend as a ferrite material to use?
Many thanks
--
Best regards,
Chris mailto:chris@...
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Just some answers:
1.? >>The isolation between transmit and SDR receive is not good enough on this product.? It will work OK for QRP but not with a transmitter using more than 10 watts.?
1.?????
? I think that there is misunderstanding :???? -30 dBm is the maximal signal level at the SDR input when 100 w TRX at full power is used.??? 100 W = +50 dBm so the insulation is? 80 dB.? This is at the highest frequency. For example at 1.8 MHz the insulation is above 90 dB. ?I will change the documentation to make that clear.
2. ? A separate RX antenna can be used just do not insert the TX antenna cable into Antenna switch module. In this case the Antenna switch will act as an extremely reliable RX protector with double protection.? The relay is grounding the input + ?heavy duty limiter which can withstand even 100 W for hundreds of milliseconds. But normally ?I have additional small relay which can switch the input of the SDR either to Antenna switch (to use TX antenna for receiving) or to RX antennas. Our active antennas have ?protection limiters (2 levels) ?. They limit the level at the SDR input to 6 V pp – no limiter, 4.2 V pp (limter 1)? 2 V pp (=10dBm limiter2). So in this case the SDR is protected both from TRX and RX antennas.
73 lz1aq
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On Tue, Jan 11, 2022 at 04:40 PM, Bob Benedict, KD8CGH wrote:
The isolation between transmit and SDR receive is not good enough on this product.? It will work OK for QRP but not with a transmitter using more than 10 watts.?
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I have the DX Engineering switch that adds a antenna port for receiving. It works super but is a pricey bugger. ?I am using a simple 2 position coax switch to use 2 different radios.? (Yaesu FTDX-3000 & Icom IC-7300) I use N4PY’s version of the LZ1AQ and it is my understanding that unlike the Pro1B and some other preamps it does not need to be powered down or grounded. I do not run big power which “may “ be another issue. NK 9G. ?Rick
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On Jan 12, 2022, at 7:29 AM, Mike Irizarry <michael.irizarry29@...> wrote:
? MFJ has one. I have used it for 5 years and it is small and works well. You can see it on the MFJ web site. DX engineering used to source it too.? On Tue, Jan 11, 2022 at 5:53 PM Steve Brodie VK4SJB < stevebrodie@...> wrote: Hi is there a tx/rx switch for the?lz1aq amp so I can use my EFHW for tx and the?lz1aq loop antenna for rx on a HF radio that doesn't support a separate rx input.
Kind regards?
Steve
VK4SJB?
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Or you could easy make one..relay..transistor, cap or 2, resistor or 2.. little metal box, 3 so239’s and 12v in.oh and a phono socket.
Would need to go in non 12v powered rx line…
Simon
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MFJ has one. I have used it for 5 years and it is small and works well. You can see it on the MFJ web site. DX engineering used to source it too.?
On Tue, Jan 11, 2022 at 5:53 PM Steve Brodie VK4SJB < stevebrodie@...> wrote: Hi is there a tx/rx switch for the?lz1aq amp so I can use my EFHW for tx and the?lz1aq loop antenna for rx on a HF radio that doesn't support a separate rx input.
Kind regards?
Steve
VK4SJB?
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Locked
Re: Proximity of Wellbrook loops to transmitting antenna
I have the DX engineering loop (formally Pixel), which is an active loop similar to yours. I have mine located about 50 feet from my TX antennas. I run anywhere from 100w to 1kw. The DX loop has a PTT disconnect input so power is removed from the electronics on transmission. The necessary distance is a function of the frequency of transmission. I mainly operate 160, 80, 40, and 20. I think a good rule of thumb is 1/2 wavelength of separation between TX and RX antennas. If you can't achieve this spacing, I would recommend disconnecting the power to the RX electronics during transmission. Hope that helps.
Mike AB4KJ
On Wed, Jan 12, 2022 at 6:43 AM Steven, M0OYR < steve@...> wrote: Hiya
Hope this is suitable for this group.
I've been using a couple of Wellbrook 1530 active receiving loops for the past 20+ years for shortwave listening with FRG100 and AR3030 receivers.
Finally got my full license and now transmitting - looking forward to building a transmitting loop!! ( I certainly have a beast of a variable capacitor for it.)
I've got a small garden with currently a W330S 10m long folded dipole and a sigma eurocomm XF-80 vertical, currently up to 100W but soon
will have antenna suitable for UK 400W once I have finished building my valve amplifier.
How resistant to damage will the wellbrook loops be when in close proximity to my transmissions? The furthest I can put them is at ground level about 3m from the dipole.
Do I have to disconnect their power supplies??? I'm worried about the pre-amps within the base of the loops. Additionally will my receivers front-ends be blown??
Cheers
Steve
M0OYR
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Locked
Re: Proximity of Wellbrook loops to transmitting antenna
?
Steve, M0OYR wrote on Jan 12 2022
?
“
I've been using a couple of Wellbrook 1530 active
receiving loops for the past 20+ years for shortwave listening with FRG100 and
AR3030 receivers.
Finally got my full license and now transmitting -
looking forward to building a transmitting loop!! ( I certainly have a beast of
a variable capacitor for it.)
I've got a small garden with currently a
W330S 10m long folded dipole and a sigma eurocomm XF-80 vertical, currently up
to 100W but soon
will have antenna suitable for UK 400W once I have finished
building my valve amplifier.
How resistant to damage will the wellbrook
loops be when in close proximity to my transmissions? The furthest I can put
them is at ground level about 3m from the dipole.
Do I have to disconnect
their power supplies??? I'm worried about the pre-amps within the base of
the loops. Additionally will my receivers front-ends be
blown??”
?
The loops are designed to withstand a
peak Field Strength F/S? of 400V/m or 1A/m
You are not likely to be able to
achieve this F/S in a Ham radio environment. I would advise that you use a relay
to disconnect the loop power to protect the Rx front end as the loops amps. can
push out a Watt or so? on the onset of clipping,
The other option is to use a
Dxengineering front end protector or similar.
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Everett N4CY
Roger Need
Ian Brooks