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IC 7300 Clock Battery

 

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.



Dave W6VYC
S tuner by PA0FRI

 

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
Re: Dunstar Filters

 

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




On Mon, Oct 7, 2024 at 11:35?AM David W Crocker via <dwcae=[email protected]> 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.
Re: Dunstar Filters

 

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




On Mon, Oct 7, 2024 at 11:35?AM David W Crocker via <dwcae=[email protected]> 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.
MagLoop RadCom Plus

 

Interesting article in the recent issue of of RadCom Plus which like QEX.

Dave W6VYC

MagLoop.pdf
MagLoop.pdf

Re: Dunstar Filters

 

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.


<OIP (1).jpg><OIP.jpg><300-21_thumbnail (9).jpg>
Re: Dunstar Filters

 

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.


<OIP (1).jpg><OIP.jpg><300-21_thumbnail (9).jpg>
Re: Dunstar Filters

 

¿ªÔÆÌåÓý

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.


<OIP (1).jpg><OIP.jpg><300-21_thumbnail (9).jpg>
Dunstar Filters

 

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.


OIP (1).jpg
OIP.jpg
300-21_thumbnail (9).jpg

RadCom Sept 2024

 

¿ªÔÆÌåÓý

I meant Oct 2024, not Sept 2024.



Begin forwarded message:

From: Hiroki Kato <hiroki@...>
Date: October 6, 2024 at 01:26:21 PDT
To: [email protected]
Subject: [QRPops] RadCom Sept 2024
Reply-To: [email protected]

?
?




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>
RadCom Sept 2024

 

¿ªÔÆÌåÓý

?




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
p42_43_Mag_loop_radcom_Oct23 - pjds edits.pdf.pdf

Re: RadCom October Issue

 

The Wizard of Portola Valley!
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.
RadCom October Issue

 

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
?
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

 

¿ªÔÆÌåÓý

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:

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

 

¿ªÔÆÌåÓý

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

 

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: Friday

 

I plan to pop by the ops site, then bike, then dine (at Green Elephant) and then check out the PAARA goodies table. Best, --David KM6RI
Re: Interstation interference book

 

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.
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