Re: 25 years of the SIERRA - Mainboard, Band Module and critical parts are available
Hi Mike,
as we started the project in 2017 all PCBs are made 2018/19. They all have plated through holes!
The vari caps (C54) are also made by the original manufacturer in 2018.
So don't worry... give it a try!
- is a non commercial pcb service for the ham radio amateur experimenter.
SIERRA files @ ARRL:
72/3 de DM5TU - sTef (STEFAN)
... -.-
DM5TU / VY1QRP - DL-QRP-AG *GM* - GQRP #8769 - CalQRP #034 - NAP #1607 - twitter.com/DM5TU
|
Re: 25 years of the SIERRA - Mainboard, Band Module and critical parts are available
Thanks Stefan - that's pretty amazing. Does "...industry quality pcbs ..." mean Industry Quality from the mid 90s where sometimes, plated through holes were not a thing? Not being critical, just curious. And very impressed that you are doing this excellent work. -- MC VK1MC
|
Hi gents, I have posted the detailed information in a new thread. /g/qrp-tech/topic/25_years_of_the_sierra/32456807?p=,,,50,0,0,0::recentpostdate%2Fsticky,,,50,2,0,32456807 72/3 de DM5TU - sTef ... -.- DM5TU / VY1QRP - DL-QRP-AG *GM* - GQRP #8769 - CalQRP #034 - NAP #1607 twitter.com/DM5TU
|
25 years of the SIERRA - Mainboard, Band Module and critical parts are available
HAPPY BIRTHDAY SIERRA!
Hi all,
with permission of Wayne Burdick, N6KR, OM Dirk, DH4YM and me - sTef DM5TU / VY1QRP are able to provide industry quality pcbs for your SIERRA project build.
The SIERRA Mainboard pcb is based on the Rev. B from 1994 as shown e.g. in the ARRL Handbook 1996/7/8. The band module pcb is good for all SIERRA versions, the original 1996 ARRL Handbook version as well as for the later version sold commercially by WILDERNESS RADIO.
Altogether we provide the following parts for your retro NorCal SIERRA build:
+ PCB of the SIERRA mainboard in Rev. B 1994. In first class quality with modifications on the interface connections pads
+ PCB for the band modules
+ VFO vari cap C54 from the original manufacturer from an new production run 2018
+ Original edge connector for the band modules pcb which fits 100% into the mainboard
For all part orders please contact Dirk DH4YM via email -> DH4YM (at) t-online (dot) de or me via our arp-tech group.
www.dh4ym.de - is a non commercial pcb service for the ham radio amateur experimenter.
SIERRA files @ ARRL:
72/3 de DM5TU - sTef (STEFAN)
... -.-
DM5TU / VY1QRP - DL-QRP-AG *GM* - GQRP #8769 - CalQRP #034 - NAP #1607 - twitter.com/DM5TU
|
Re: 4.096MHz matched crystal sets (6pcs) NC40A 40m IF#2 project
VXOs, the ability to vary the rock is directly tied to the fixed C (holder and crystal)
and can be expressed by PPM so naturally higher you go the more you can pull
a rock expressed in Khz.
The big problem is for 100 crystals from 100 lots even from the same vendor
that variability will be individual to the each crystal. That's never minding how
close they are to the nominal frequency.
Since the SI570 and SI5351 I stopped bothering with rocks for variable oscillators.
For filters The criteria is different and matched is the first factor. The frequency
for a given bandwidth broadly determines the termination impedance as well
as widest attainable bandwidth with good shape factor. I've found for SSB
work 5 crystals are at the low end of acceptable and shave several radios
where the filter is a cascade of 7 or as many as 10 to get decent RX skirts
at SSB widths. CW 4 will do for a 500hz filter. Lots of Superhet radios
over the years so lots of filters built.
The yabut is that using Tayloe base band converter and SI5351 an analog
phasing design works well and solved the crystal question totally. Opamps
are cheap and a 3rd order all-pass is cheaper and easily reproduced.
Allison
--
Please reply on the group, no private emails we as a group share info that way.
|
Re: 4.096MHz matched crystal sets (6pcs) NC40A 40m IF#2 project
Chuck is correct. I did all the matching of crystals for all NorCal kits.
|
4.096MHz matched crystal sets (6pcs) NC40A 40m IF#2 project
One of the purposes of experimenting with various IF frequencies and as a
side project was to measure the pulling ability of -U vs -S as a function
of the frequency as the crystal frequencies chosen vary from 4.0MHz to
13.5MHz in both form factors.? I've always posted that the -U should be
able to be pulled a larger range in a VXO than a -S.? -U operates in
a shear mode and the -U operates in a flex mode.
Instead of using up a lot of plastic, which I probably should do to
preserve the data for each of the crystals, I use a vector board with
M3 stand offs as shown in the attached photograph with 100 9.000MHz
HC-49S crystal units.? In groups of 10 and I did add some numbers
using a labeling machine so as not to get confused.? I carefully store
the setup in a plastic box ($1 store) for duration of the testing and
use of the crystals.? You can number them with a sharpie and later erase
the markings with an alcohol pad found at restaurants or in large
quantities in the medicine sections of stores.? Or just a plain bottle
of alcohol with a cloth.
This group is going to benefit with an ebay find of mine over a decade
ago.? I bought over a thousand 4.096MHz HC-49U crystals for a cheap
price with free shipping.? You just use another 1MHz addition to the
LO frequency for 40m.? I will match them in groups of 6 each to within
20Hz in a Colpitts oscillator board that is in the groups file section.
Mail me offline and I'll start a list and post the final winning solution
to get the lowest cost of shipping and you can have a matched set for
my costs.
But, I need those of you that ship free parts to others to tell me
what packaging do you use and what is the cheapest postage rate you
get.? I see WA5BDU ships a uP chip for $4 including the postage.
Don't know how he does.? Inquiring minds want to know.
50 free matched crystals to the guy who comes up with the best idea posted
to the list.
I will match crystals in groups of 6 and give them away for my
cost of postage and $1 for the envelope, if the winner above comes
up with a cheap supply of same.
In matching, I use a NorCal FCC-1, since it is good to 1Hz calibrated
with a GPSDO at 10 000 000 MHz (ISO number format).? I was wondering
why no one in this group has not done the Gerber files as the hex
code is available from the ARRL.? I just love the critter.
I was going to the lab to prototype an oscillator and WA5BDU AFA as
a possible board project for the group to have a lab frequency counter
for cheap cheap.? He has the output to 1Hz for 1sec sample rate.
I did get the A/C fixed.? Can you believe $381 for two caps for two
motors, one outside and one inside?? I know.? We can go to a electrical
supply and get the caps, if I had known what the problem was.
To keep me on track.? I'm leaving the desk here for 6 hours to go to
the lab to get the NC40A built at IF of 4.096MHz for 40m and the frequency
counter project.? I will not be documenting the build as usual to save
a whole lot of time.
I'll do a 9.000MHz version sometime this weekend and then I will do a
video showing a comparison using a neat procedure that is reproduced with
same set of signals on both bands in my lab.
Film at 11 as I'm guessing around 10pm to get back to the terminal.
chuck, k7qo
OH.? And for the matching, I will do 100 at a time using the
board shown in the photo and after writing down the freq for each,
I just pick 6 at a time that match within 20Hz.? You can adjust some caps in the
BFO? and transmit mixer to pull the resulting band into the filter
band pass.? The original NorCal came with all in 20Hz and I assume that
Doug did all the work in matching for the original kit or he got volunteers.
Added photograph of six Pringles potato chip recycled containers showing
full or almost full except for can #3 from left to right.? Some 9.0MHz
on the left for later.
toggle quoted message
Show quoted text
On 7/12/19 1:39 PM, Michael Babineau wrote: On Fri, Jul 12, 2019 at 11:40 AM, chuck adams wrote:
I will, in the next week, build another NC40A, but I found some
9.000MHz crystals for a nickel each and I wanted to do an
article of HC-49U vs HC-49S using the same IF frequency doing
a detailed matching procedure two ways and investigate the
results.
Chuck, I for one will be interested in the results. I used the HC-49S for my Norcal 40a and
it seems to work well, but I keep wondering if it would work even better with HC-49U crystals.
One thing I do know, thanks to NA5N, is that you can't "pull" HC-49S crystals as much as HC-49U.
Paul's suggestion of picking a BFO crystal for the Norcal 40a that was higher in frequency than
the filter crystals was a good idea, as I was just able to adjust the BFO so that signals were just in the
middle of the filter passband, with very little wiggle room to spare.
I ordered 100 X 4.9152 Mhz HC-49S crystals from China and the trick that I used to match them for the NC40a worked very
well (I was able to get a few sets matched to within 2 Hz of each other). I used little resealable clear plastic bags from the dollar-store
(one per crystal) and a sequential numbering system (1-100) written on each bag with a Sharpie to correlate the crystal to its
measured frequency in a spreadsheet. Once I was done all of the measurements I then sorted the spreadsheet on frequency (lowest to highest)
and then it was simple to make groupings of adjacent crystal bag numbers. The actual matching was just a matter of physically locating the numbered crystal bags
that corresponded to the numbers in the spreadsheet making up a set of 4 (actually I used 5 as I discovered that the TX mixer crystal wants to be really
close to filter crystal values). I then took NA5Ns advice and picked a crystal for the BFO from the bottom of the my sorted list. This worked like a charm.
I labelled each crystal bag so I would know which crystals were which (i.e BFO/TXO/Filter) and put the 6 of them into a slightly larger resealable bag.
I found crystal matching to be oddly relaxing (Chuck you are apparently not the only one with OCD-tendencies ;-) ).
Cheers
Michael
P.S. I am still waffling on whether to order an Organic 5-Watter. I have such a backlog of building to do and I already have a partially built QCX40 on the bench at the moment.
I think that it is just a matter of time though before I cave. The big question is always what band? I got around that problem with the One Watter by building one for 40m/30m and 20m
(why buy one when you can get three for 3 times the price ;-) ).
|
Re: 4.9152MHz HC-49U crystals
On Fri, Jul 12, 2019 at 11:40 AM, chuck adams wrote:
I will, in the next week, build another NC40A, but I found some
9.000MHz crystals for a nickel each and I wanted to do an
article of HC-49U vs HC-49S using the same IF frequency doing
a detailed matching procedure two ways and investigate the
results.
Chuck, I for one will be interested in the results. I used the HC-49S for my Norcal 40a and it seems to work well, but I keep wondering if it would work even better with HC-49U crystals. One thing I do know, thanks to NA5N, is that you can't "pull" HC-49S crystals as much as HC-49U. Paul's suggestion of picking a BFO crystal for the Norcal 40a that was higher in frequency than the filter crystals was a good idea, as I was just able to adjust the BFO so that signals were just in the middle of the filter passband, with very little wiggle room to spare. I ordered 100 X 4.9152 Mhz HC-49S crystals from China and the trick that I used to match them for the NC40a worked very well (I was able to get a few sets matched to within 2 Hz of each other). I used little resealable clear plastic bags from the dollar-store (one per crystal) and a sequential numbering system (1-100) written on each bag with a Sharpie to correlate the crystal to its measured frequency in a spreadsheet. Once I was done all of the measurements I then sorted the spreadsheet on frequency (lowest to highest) and then it was simple to make groupings of adjacent crystal bag numbers. The actual matching was just a matter of physically locating the numbered crystal bags that corresponded to the numbers in the spreadsheet making up a set of 4 (actually I used 5 as I discovered that the TX mixer crystal wants to be really close to filter crystal values). I then took NA5Ns advice and picked a crystal for the BFO from the bottom of the my sorted list. This worked like a charm. I labelled each crystal bag so I would know which crystals were which (i.e BFO/TXO/Filter) and put the 6 of them into a slightly larger resealable bag. I found crystal matching to be oddly relaxing (Chuck you are apparently not the only one with OCD-tendencies ;-) ). Cheers Michael P.S. I am still waffling on whether to order an Organic 5-Watter. I have such a backlog of building to do and I already have a partially built QCX40 on the bench at the moment. I think that it is just a matter of time though before I cave. The big question is always what band? I got around that problem with the One Watter by building one for 40m/30m and 20m (why buy one when you can get three for 3 times the price ;-) ). -- Michael VE3WMB / VA2NB
|
Re: 4.9152MHz HC-49U crystals
At the same link, in the upper right side of the web page, you can get 50 pcs 10.245 MHz, 9 MHz, 10 MHz for $7.50 and for $13.58, you can get 100 pcs of 9 MHz in HC-49U!
-Steve K1RF
toggle quoted message
Show quoted text
-----Original Message----- From: chuck adams Sent: Friday, July 12, 2019 11:40 AM To: [email protected]Subject: [qrp-tech] 4.9152MHz HC-49U crystals In a quick search I found the following. 50pcs 4.9152MHz HC-49U crystals for $7.20 USD with free shipping to the US. They have 296,991 lots available at the time, but that includes the same deal for 5.000MHz and 6.000MHz. I calculate that is $0.144/crystal unit. Let me know if you find a better deal other than buying a 1,000 units per frequency. It looks like to me that there is interest in a number of people doing the NC40A. A number of us have boards that were done in China from the layout that is in the files section and documentation is also in the directory. As member of the group go to the groups.io web page and log in and access the files section. Directory is on the 5th page and has the name /g/qrp-tech/files/Winter%202018%20Project%20%231%20--%20%20NorCal40A%20qrp-tech%20PCBand hopefully the link will be clickable. The Gerber zip file is second from the bottom. Old pricing was $5.49 for 10 boards. It's now $5 but you have to add on DHL shipping for another $17 or so. I will, in the next week, build another NC40A, but I found some 9.000MHz crystals for a nickel each and I wanted to do an article of HC-49U vs HC-49S using the same IF frequency doing a detailed matching procedure two ways and investigate the results. You may have already done this. 9.000MHz used to be the standard IF back in the day as you could do multiband radios with the same IF frequency. It's the reason for the LSB and USB standards for the ham bands, which you are free to ignore at your own choosing. Using the 9.000MHz IF frequency means raising the VFO by an additional 2.0MHz for the NC40A, but that doesn't bother me. FYI chuck, k7qo, shopping the Internet for deals
|
Re: 4.9152MHz HC-49U crystals
My 6M DDB phasing rig uses a 14mhz VFO. IF one uses good NPO and N750 caps
and tested it can be remarkably stable.
Allison
--
Please reply on the group, no private emails we as a group share info that way.
|
Re: Crystal Filter research beginnings
1.? Look at the web page for Jim, K8IQY.? Must read and look at his table (on a separate page
??? that he links to.? Also note his research on grounding the crystal case.? Diz in the 5W
??? and 1W grounds the crystal cases.? I don't, but that his my own OCD problem.
Oooops.? Typo.? I'm the one with OCD problems, not Diz. chuck, k7qo
|
Crystal Filter research beginnings
I apologize for the rash of postings.
Here is a quick list of URLs to see some online material
on crystals and matching methodology.
~
1.? Look at the web page for Jim, K8IQY.? Must read and look at his table (on a separate page
??? that he links to.? Also note his research on grounding the crystal case.? Diz in the 5W
??? and 1W grounds the crystal cases.? I don't, but that his my own OCD problem.
2.? The last link by Murata.? Section 3.? Note the effect of a 1pF error in the interstage
??? capacitors and the effect of the shape and bandwidth.? How many of us match the caps.
??? Looks like it is more important than matching the crystals at first glance.
3.? Giangandi has an online calculator with choices of the number of poles for the filter.
FYI
chuck, k7qo
|
Re: 4.9152MHz HC-49U crystals
If one takes extra care in using NP0 parts where specified and using
the -7 ferrite core you should not have any problems.? There are a
large number of designs that use 4MHz and higher local oscillators.
The SWL-20 series from Dave Benson, K1SWL, used used a 9.00MHz IF
frequency and the LO ran at 5.0XXMHz with no problems.? Dave used
some polystyrene caps in the Colpitts LO and if you go and look at the electrical
properties of the material you can see why he used them.? Of course
they are getting much harder to find and probably pricey now. Take
up some real estate on the PCB also.
I'll let you know how much I luck I have with the project.? Film at
11.
First thing I did was screw up the math again.
7.030MHz?? 4.915MHz IF?? gives a LO of 2.115MHz
7.030MHz?? 9.000MHz IF?? gives a LO of 1.970MHz
so going to a lower LO frequency.? Yes, should be more stable.
Bad news.? Smaller tuning BW, if my intuition is correct and it's
not always right when using the same varactor diode in the circuit.
But, Dave had another cap that you could change to effect the range.
For 20m version of the NC40A
14.060MHz?? 9.000MHz IF? gives a LO of 5.060MHz
which is doable as noted at start.? Hoping for a larger tuning
range.
Or go to a choice of 11.059MHz, 11.289MHz, 12.000MHz or 12.084MHz
IF for which I have some crystals on hand to try.
See, these options will take some time, money and energy to get
around to.? One of these days.? I love the quote from the
movie 'Knight and Day' about one of these days never getting here.
Film at 11
chuck, k7qo
toggle quoted message
Show quoted text
On 7/12/19 9:53 AM, Peter Filiberti wrote: Hi Chuck, will raising the frequency of the VFO alter it's stability? I'm super impressed with the norcal I built's vfo stability and I read somewhere that the lower frequency vfo's are more temp stable.????
Peter
|
Re: 4.9152MHz HC-49U crystals
Hi Chuck, will raising the frequency of the VFO alter it's stability? I'm super impressed with the norcal I built's vfo stability and I read somewhere that the lower frequency vfo's are more temp stable.????
Peter
|
Re: 4.9152MHz HC-49U crystals
The original requirement was matched within 25Hz.
Bob Macklin
K5MYJ
Seattle, Wa.
"Real Radios Glow In The Dark"
toggle quoted message
Show quoted text
----- Original Message ----- From: "Mark G?NMY" <mark.g0nmy@...> To: < [email protected]> Sent: Friday, July 12, 2019 9:01 AM Subject: Re: [qrp-tech] 4.9152MHz HC-49U crystals Hi Chuck I ordered 10 xtals a week ago they are on a slow boat from China. Then I will have to start checking each ones accuracy. How accurate do they need to be for the filter Chuck? Oh and Im in the UK so doubt it would be cheap enough for you to ship here. Cheers Mark G0NMY ================================================================================================== - *May the MORSE be with you!* - *My Ham Radio Blog <>* - G?NMY G-QRP #12875 <> - G-QRP clublog <> - UKSMG club log <> - *???q? ??o p??oq??? ? ?nq ? ???? ?s?? ??? s? s???* - [image: UKSMG.ORG] <> - *UKSMG.ORG <>* On Fri, 12 Jul 2019 at 16:40, chuck adams <chuck.adams.k7qo@...> wrote: In a quick search I found the following.
50pcs 4.9152MHz HC-49U crystals for $7.20 USD with free shipping
to the US.
They have 296,991 lots available at the time, but that includes
the same deal for 5.000MHz and 6.000MHz. I calculate that is
$0.144/crystal unit. Let me know if you find a better deal
other than buying a 1,000 units per frequency.
It looks like to me that there is interest in a number of
people doing the NC40A. A number of us have boards that were
done in China from the layout that is in the files section
and documentation is also in the directory. As member of
the group go to the groups.io web page and log in and access
the files section. Directory is on the 5th page and has the name
/g/qrp-tech/files/Winter%202018%20Project%20%231%20--%20%20NorCal40A%20qrp-tech%20PCB
and hopefully the link will be clickable. The Gerber zip file is
second from the bottom. Old pricing was $5.49 for 10 boards. It's
now $5 but you have to add on DHL shipping for another $17 or so.
I will, in the next week, build another NC40A, but I found some
9.000MHz crystals for a nickel each and I wanted to do an
article of HC-49U vs HC-49S using the same IF frequency doing
a detailed matching procedure two ways and investigate the
results. You may have already done this. 9.000MHz used to
be the standard IF back in the day as you could do multiband
radios with the same IF frequency. It's the reason for
the LSB and USB standards for the ham bands, which you are
free to ignore at your own choosing.
Using the 9.000MHz IF frequency means raising the VFO by an
additional 2.0MHz for the NC40A, but that doesn't bother me.
FYI
chuck, k7qo, shopping the Internet for deals
|
Re: 4.9152MHz HC-49U crystals
I have 50 pcs of 4.915MHz HC-49 crystals on my Mouser order for next month.
I'm going to build a test setup (oscillator/counter) to try matching
crystals.
We will see how that works. There are other old designs out there that use
similar filters.
Do I want to make a career out of matching crystals?
Bob Macklin
K5MYJ
Seattle, Wa.
"Real Radios Glow In The Dark"
toggle quoted message
Show quoted text
----- Original Message ----- From: "chuck adams" <chuck.adams.k7qo@...> To: < [email protected]> Sent: Friday, July 12, 2019 8:40 AM Subject: [qrp-tech] 4.9152MHz HC-49U crystals In a quick search I found the following.
50pcs 4.9152MHz HC-49U crystals for $7.20 USD with free shipping
to the US.
They have 296,991 lots available at the time, but that includes
the same deal for 5.000MHz and 6.000MHz. I calculate that is
$0.144/crystal unit. Let me know if you find a better deal
other than buying a 1,000 units per frequency.
It looks like to me that there is interest in a number of
people doing the NC40A. A number of us have boards that were
done in China from the layout that is in the files section
and documentation is also in the directory. As member of
the group go to the groups.io web page and log in and access
the files section. Directory is on the 5th page and has the name
/g/qrp-tech/files/Winter%202018%20Project%20%231%20--%20%20NorCal40A%20qrp-tech%20PCB
and hopefully the link will be clickable. The Gerber zip file is
second from the bottom. Old pricing was $5.49 for 10 boards. It's
now $5 but you have to add on DHL shipping for another $17 or so.
I will, in the next week, build another NC40A, but I found some
9.000MHz crystals for a nickel each and I wanted to do an
article of HC-49U vs HC-49S using the same IF frequency doing
a detailed matching procedure two ways and investigate the
results. You may have already done this. 9.000MHz used to
be the standard IF back in the day as you could do multiband
radios with the same IF frequency. It's the reason for
the LSB and USB standards for the ham bands, which you are
free to ignore at your own choosing.
Using the 9.000MHz IF frequency means raising the VFO by an
additional 2.0MHz for the NC40A, but that doesn't bother me.
FYI
chuck, k7qo, shopping the Internet for deals
|
Re: 4.9152MHz HC-49U crystals
Hi Chuck I ordered 10 xtals a week ago they are on a slow boat from China. Then I will have to start checking each ones accuracy. How accurate do they need to be for the filter Chuck? Oh and Im in the UK so doubt it would be cheap enough for you to ship here. Cheers Mark G0NMY ================================================================================================== - *May the MORSE be with you!* - *My Ham Radio Blog <>* - G?NMY G-QRP #12875 <> - G-QRP clublog <> - UKSMG club log <> - *???q? ??o p??oq??? ? ?nq ? ???? ?s?? ??? s? s???* - [image: UKSMG.ORG] <> - *UKSMG.ORG <>* On Fri, 12 Jul 2019 at 16:40, chuck adams <chuck.adams.k7qo@...> wrote: In a quick search I found the following.
50pcs 4.9152MHz HC-49U crystals for $7.20 USD with free shipping
to the US.
They have 296,991 lots available at the time, but that includes
the same deal for 5.000MHz and 6.000MHz. I calculate that is
$0.144/crystal unit. Let me know if you find a better deal
other than buying a 1,000 units per frequency.
It looks like to me that there is interest in a number of
people doing the NC40A. A number of us have boards that were
done in China from the layout that is in the files section
and documentation is also in the directory. As member of
the group go to the groups.io web page and log in and access
the files section. Directory is on the 5th page and has the name
/g/qrp-tech/files/Winter%202018%20Project%20%231%20--%20%20NorCal40A%20qrp-tech%20PCB
and hopefully the link will be clickable. The Gerber zip file is
second from the bottom. Old pricing was $5.49 for 10 boards. It's
now $5 but you have to add on DHL shipping for another $17 or so.
I will, in the next week, build another NC40A, but I found some
9.000MHz crystals for a nickel each and I wanted to do an
article of HC-49U vs HC-49S using the same IF frequency doing
a detailed matching procedure two ways and investigate the
results. You may have already done this. 9.000MHz used to
be the standard IF back in the day as you could do multiband
radios with the same IF frequency. It's the reason for
the LSB and USB standards for the ham bands, which you are
free to ignore at your own choosing.
Using the 9.000MHz IF frequency means raising the VFO by an
additional 2.0MHz for the NC40A, but that doesn't bother me.
FYI
chuck, k7qo, shopping the Internet for deals
|
4.9152MHz HC-49U crystals
In a quick search I found the following. 50pcs 4.9152MHz HC-49U crystals for $7.20 USD with free shipping to the US. They have 296,991 lots available at the time, but that includes the same deal for 5.000MHz and 6.000MHz.? I calculate that is $0.144/crystal unit.? Let me know if you find a better deal other than buying a 1,000 units per frequency. It looks like to me that there is interest in a number of people doing the NC40A.? A number of us have boards that were done in China from the layout that is in the files section and documentation is also in the directory.? As member of the group go to the groups.io web page and log in and access the files section.? Directory is on the 5th page and has the name /g/qrp-tech/files/Winter%202018%20Project%20%231%20--%20%20NorCal40A%20qrp-tech%20PCBand hopefully the link will be clickable.? The Gerber zip file is second from the bottom.? Old pricing was $5.49 for 10 boards. It's now $5 but you have to add on DHL shipping for another $17 or so. I will, in the next week, build another NC40A, but I found some 9.000MHz crystals for a nickel each and I wanted to do an article of HC-49U vs HC-49S using the same IF frequency doing a detailed matching procedure two ways and investigate the results.? You may have already done this.? 9.000MHz used to be the standard IF back in the day as you could do multiband radios with the same IF frequency.? It's the reason for the LSB and USB standards for the ham bands, which you are free to ignore at your own choosing. Using the 9.000MHz IF frequency means raising the VFO by an additional 2.0MHz for the NC40A, but that doesn't bother me. FYI chuck, k7qo, shopping the Internet for deals
|
Re: mating ferrite - no gaps
I used wet silicon carbide to lap pieces, wet emery works well too. I
found that even the smallest gap will indeed lower the effective mu.
TV yokes that's ok as it also increases the flux saturation point for
the assembly over a solid piece.
For RF work it can be helpful but for applications that require high mu
to live with the result. An example of a built up ferrite stack for a loop.
Laminated with no end to end gaps works very well. However end to
end gaps produce a measurable reduction in effective mu.
If you glue up the assembly use the thinnest bond possible and clamp
it. Avoid epoxy with metal fillers.
Allison
--
Please reply on the group, no private emails we as a group share info that way.
|
Am attempting to join multiple complex-shaped ferrite pieces, namely
TV-yoke cores. Many of these are split into two halves. In any case,
they will be re-wound with copper in a way that will direct magnetic
paths through the join gap. More that a few will be joined.
A gap-free joint is wanted, so magnetic paths are evenly distributed
through the joint and not confined to small regions where mating
surfaces contact while other regions have some air-gap.
Seems to me that ferrite is glass-like, so mating? surfaces might use
lapping techniques. Mirror-like surfaces not required. Wonder if
anyone has experience here (I don't)?
Would wet emery papers work? Aluminum oxide or silicon carbide
powders?
|
sTef - DM5TU/VY1QRP
