I plan to be at the Bay Cafe for lunch and ops at the Baylands around 1:30
Dave W6VYC
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Re: IC 7300 Clock Battery
Thanks Dave, I don't think the clock in my 7300 has ever been correct. Thanks for passing this fix on. I will forward to my engineering department, my husband.?
?
Joy
N6GO
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Very? interesting postings.? But are we using a cannon to kill a fly?? These filters are all good and do the job I am sure.? But they are expensive,? and handle hundreds of? Watts.
?
Joy runs qrp. A KX2 I believe,? and she is running? 10 W at the most.? I don't think I have ever seen anyone out at Baylands who wasn't running qrp. Correct me if I? am wrong.? So we have one qrp station on 20 meters who wants to avoid interference from? other stations on other bands who are also running qrp.? Why does she need a filter that will hand hundreds of Watts and is very expensive?
?
One of the things that attracted me to qrp was that you don't need a lot of money for equipment? ((at least you didn't? before Elecraft came on the scene) and I love and have their gear).
?
It's easy to build a band pass filter in an altoids tin.? Hiroki how about you and I build one and see how it works.? ?Build it and test it empirically.? ?Is the challenge accepted?? The rest of you are welcome to try too.
?
I love this group because they actually do ham radio.
?
Doug
?
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How many of us have a 7300 with the clock battery run down and time constantly needs setting.
Here is a nice solution by installing a rechargeable battery LR 2032 and a 1K resistor.
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This is the original source of the S Tuner design that was in the FARS homebrew contest. The unit at FARS was nicely built in a non-conductive wooden/plexiglass box. He claimed this tuner architecture was more efficient than the Palsar tuner.
Dave W6VYC
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Christopher,
Nice looking products with very good adjacent band rejection. The low power toroid versions are reasonably priced.
Dave W6VYC
On Monday, October 7, 2024 at 01:47:12 PM PDT, Christopher AI6KG <ch@...> wrote:
We (AB6RF and me) have been pretty happy with K6WX's filters and diplexers at Pacificon.? ? We rarely run more than 500W on any station (due to AC power limitations).? They run cool; we have never plugged in the fans.
VA6AM also has some good designs as well.? ? We have used some of these too at the station.
73 de AI6KG
These are the bandpass filters that have been used for years. Don't know if you can find them anymore. They are coupled resonator type filters using air core inductors. If you really want, you can make your own. See attached.
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We (AB6RF and me) have been pretty happy with K6WX's filters and diplexers at Pacificon.? ? We rarely run more than 500W on any station (due to AC power limitations).? They run cool; we have never plugged in the fans.
VA6AM also has some good designs as well.? ? We have used some of these too at the station.
73 de AI6KG
These are the bandpass filters that have been used for years. Don't know if you can find them anymore. They are coupled resonator type filters using air core inductors. If you really want, you can make your own. See attached.
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Interesting article in the recent issue of of RadCom Plus which like QEX.
Dave W6VYC
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If you have one built, let's put it in a VNA.? Either a nanoVNA, or my Rigol.? Cliff
On October 7, 2024 12:38:27 PM PDT, "David W Crocker via groups.io" <dwcae@...> wrote:
The values can be scaled by the ratio of the frequencies. ie: 21/28 for the multiplier for the inductors and capacitors to scale to 10 meters. if you want to see the response of various filters, use a program like Elsie. Take a look at the filters used by Rick and Joanna which are the one used by PAARA at Field Day and Pacificon.
Dave W6VYC
On Monday, October 7, 2024 at 11:43:22 AM PDT, Hiroki Kato <hiroki@...> wrote:
Dave,
Do you have any data in re how sharp/effective this filter is? I'd like to try building one (or more for other bands besides 21MHz).
Hiroki AH6CY On Oct 7, 2024, at 11:34 AM, David W Crocker via < dwcae@...> wrote: These are the bandpass filters that have been used for years. Don't know if you can find them anymore. They are coupled resonator type filters using air core inductors. If you really want, you can make your own. See attached.
|
The values can be scaled by the ratio of the frequencies. ie: 21/28 for the multiplier for the inductors and capacitors to scale to 10 meters. if you want to see the response of various filters, use a program like Elsie. Take a look at the filters used by Rick and Joanna which are the one used by PAARA at Field Day and Pacificon.
Dave W6VYC
On Monday, October 7, 2024 at 11:43:22 AM PDT, Hiroki Kato <hiroki@...> wrote:
Dave,
Do you have any data in re how sharp/effective this filter is? I'd like to try building one (or more for other bands besides 21MHz).
On Oct 7, 2024, at 11:34 AM, David W Crocker via < dwcae@...> wrote: These are the bandpass filters that have been used for years. Don't know if you can find them anymore. They are coupled resonator type filters using air core inductors. If you really want, you can make your own. See attached.
|
Dave,
Do you have any data in re how sharp/effective this filter is? I'd like to try building one (or more for other bands besides 21MHz).
toggle quoted message
Show quoted text
On Oct 7, 2024, at 11:34 AM, David W Crocker via < dwcae@...> wrote:
These are the bandpass filters that have been used for years. Don't know if you can find them anymore. They are coupled resonator type filters using air core inductors. If you really want, you can make your own. See attached.
|
These are the bandpass filters that have been used for years. Don't know if you can find them anymore. They are coupled resonator type filters using air core inductors. If you really want, you can make your own. See attached.
|
I meant Oct 2024, not Sept 2024.
toggle quoted message
Show quoted text
?
Jeff’s call sign, AJ6WX, was corrected in the final printed version. The mag loop has been modified to allow 20m operation by adding an additional 50pF butterfly variable capacitor. ?
Hiroki AH6CY
<p42_43_Mag_loop_radcom_Oct23 - pjds edits.pdf.pdf>
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Jeff’s call sign, AJ6WX, was corrected in the final printed version. The mag loop has been modified to allow 20m operation by adding an additional 50pF butterfly variable capacitor. ?
Hiroki AH6CY
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The Wizard of Portola Valley!
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Re: Interstation interference book
I don't sell the filters, Hans Summers does.? ?But my curiosity is? up.? I am going to build a filter and send it to Joy to try.
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Hiroki strikes again this month with an article about his mag loop remote controller.? He credits Jeff Reagan for the dual stepper motor idea.? He also credits 6 others for help preparing the article.? I give Hiroki credit for being a very creative inventor.
?
Bob KF6ABC
?
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Re: Interstation interference book
Clif,
Morgan filters look like the filters I would also recommend.
Thanks for pointing them out.... Dave W6VYC
On Saturday, October 5, 2024 at 05:06:39 PM PDT, Cliff Sojourner K6CLS via groups.io <cls@...> wrote:
my FTdx10 was getting massive front end overload from KNEW, KRE,
etc., on the ROV long wire antenna.
recently I bought a Morgan AM BCB filter.?
it is very high quality construction, very sharp skirts, deep
nulls.? really does the job!!!? handles 100w, passive, so doesn't
need a relay, getting connected to the radio TX line, etc.
They offer band pass filters for all HF ham bands, too.
Cliff-bob sez 2 thumbs up
On 10/5/24 16:58, David W Crocker via
groups.io wrote:
Doug,
Good bandpass filters use air
core inductors in a coupled resonator configuration which
gives lower losses and better skirts. You used to be able to
get these filters for around $100 for each band but don't know
who makes them these days. The reason I did not recommend that
Joy buy the $50 filter was the price. Also, you need to put
filters on the offending transmitters as most of the
interference comes for phase noise which is broadband and
shows up in band. The filters have to be installed with 50
ohms on both sides, so if your antenna isn't 50 ohms you need
to use a tuner between the filter and the antenna.
One of the best tricks is to
get everybody to use Magloops which are really nice bandpass
filters and an antenna.
Joy,? If you want to
experiment with these filters buy them from Doug.
Read the book that I found if
you want to see what the pros think.
Dave W6VYC
On Thursday, October 3, 2024 at 06:19:44 PM PDT, Doug
Hendricks <ki6ds1@...> wrote:
Dave,? I am curious as to why you don't think a
band pass filter can be home brewed.? I have seen
several examples on you tube that seem to work fine.?
And, back in the 90's, I used to go to the Zuni Loop
for field day.? Cam Hartford had homebrew band pass
filters for 80, 40, 20, 15 and 10.? We never had a
problem with interference and they worked great.
?
Having said that I would not advise Joy to build
one of the filters she mentioned either,? but the
reason is that it's way over priced.? I would suggest
that she order one from Qrp Labs.? It's only $4.90,
NOT $40!!!? It can easily be mounted in an Altoids
tin.
|
Re: Interstation interference book
by the way, good catch on this book.? I'm really enjoying reading
it. lotsa good stuff in there.? Cliff K6CLS CM87
On 10/2/24 11:33, David W Crocker via
groups.io wrote:
toggle quoted message
Show quoted text
Joy was asking about how to
use a bandpass filter to limit interference at the Baylands. I
don't recommend that you buy the filter. It is difficult to
build analog filters good enough to limit interference. There
are some good commercial filters that have been used during
field events (InRad triplexer). Check out the filters that are
used at Pacificon.
I found this interesting book
that might help. see attached.
Dave W6VYC
|
Re: Interstation interference book
my FTdx10 was getting massive front end overload from KNEW, KRE,
etc., on the ROV long wire antenna.
recently I bought a Morgan AM BCB filter.?
it is very high quality construction, very sharp skirts, deep
nulls.? really does the job!!!? handles 100w, passive, so doesn't
need a relay, getting connected to the radio TX line, etc.
They offer band pass filters for all HF ham bands, too.
Cliff-bob sez 2 thumbs up
On 10/5/24 16:58, David W Crocker via
groups.io wrote:
toggle quoted message
Show quoted text
Doug,
Good bandpass filters use air
core inductors in a coupled resonator configuration which
gives lower losses and better skirts. You used to be able to
get these filters for around $100 for each band but don't know
who makes them these days. The reason I did not recommend that
Joy buy the $50 filter was the price. Also, you need to put
filters on the offending transmitters as most of the
interference comes for phase noise which is broadband and
shows up in band. The filters have to be installed with 50
ohms on both sides, so if your antenna isn't 50 ohms you need
to use a tuner between the filter and the antenna.
One of the best tricks is to
get everybody to use Magloops which are really nice bandpass
filters and an antenna.
Joy,? If you want to
experiment with these filters buy them from Doug.
Read the book that I found if
you want to see what the pros think.
Dave W6VYC
On Thursday, October 3, 2024 at 06:19:44 PM PDT, Doug
Hendricks <ki6ds1@...> wrote:
Dave,? I am curious as to why you don't think a
band pass filter can be home brewed.? I have seen
several examples on you tube that seem to work fine.?
And, back in the 90's, I used to go to the Zuni Loop
for field day.? Cam Hartford had homebrew band pass
filters for 80, 40, 20, 15 and 10.? We never had a
problem with interference and they worked great.
?
Having said that I would not advise Joy to build
one of the filters she mentioned either,? but the
reason is that it's way over priced.? I would suggest
that she order one from Qrp Labs.? It's only $4.90,
NOT $40!!!? It can easily be mounted in an Altoids
tin.
|
David W Crocker
Cliff Sojourner K6CLS
.jpg)
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David