[nrv-hams] Pass Band Filters

[Russ Abbey]

Hi Carter,
I have 3 soldering irons you can use if needed.  They were given to me to
use for a future school club here in Floyd if it ever gets off of the
ground. :(  Let me know if you need them and I will bring them into you or
meet you for coffee?  What ever is needed here.  I would also lie to be
involved with this, but you know what is going on here.  If Donnie can make
an ugly schematic and a list of ugly materials, I would love to see it and
build one here also.
73
Russ, KG4MAV

On Thu, Dec 1, 2011 at 4:40 PM, Carter Craigie <carter128 at verizon.net>wrote:

> Hi fellow NRV ARC members,
>
> At last Monday evening's club meeting I introduced, as new business, a plan
> for our club to become involved in making 4 pass band filters, expressly
> intended to alleviate the interference such as we had at last year at Field
> Day (FD). The CW station got into the SSB stations, and vice-versa. We
> spent
> a fair amount of operating time trying to reduce the interference, and were
> only somewhat successful. So we're thinking about FD 2012 already! Read on.
>
> Donnie Coleman, AB4I, has a solution, one that has worked in years past:
> something called bandpass filters. Basically speaking, if an op is on 80
> meters CW, he/she won't even hear the other transmitters (SSB, CW, or DATA)
> that are simultaneously operating on any of the other bands.  It would be
> like that CW station were the only one there at FD!  And the same would be
> true for the other station(s)  as well: the SSB operators would not hear
> the
> CW station on the air, unless then switched to the same band with the CW
> station.
>
> This sounds like a really good idea to me, especially as I learned that the
> club has used a very similar bandpass filter model before, many years ago,
> and it worked.
>
> The idea would be to have club members build four (4) of these filters, so
> that, at some time in the future, we might want to go from Class 3A to
> Class
> 4A, meaning we'd be having 4 stations running on the air at the same
> time--with no interference from each other, so long as we stay on 4
> different meter bands. This sounds pretty good to me, and it did to all the
> members who were at Monday's meeting.
>
> At the meeting, Donnie spoke about the project, and passed around a sample
> of what one of the filters would look like. This was a prototype he had
> built, and was done using something called "ugly construction," but it was
> enough for all of us to see the ten (10) toroids, each wound with
> variations
> of 1, 2, 3, or 4 windings of wire.
>
> We could also see the capacitors in place, already soldered to the PC board
> that Donnie has made, with a rotary switch to select the band.
> Indeed, he will make and donate all four of the PC boards and all of the
> wire needed to do the winding of the 40 toroids--ten per each bandpass
> filter.
>
> Kay and I have already purchased the various parts. So there would be no
> expense to the club, and the treasury won't be hit up for any costs. What
> WILL be expected, though, is for enough of us club members to come to the
> Dublin Fire House on a Saturday morning to do the toroid winding and the
> capacitor soldering, and the kit assembling.
>
> This should be a real learning experience for us--and a lot of fun as well.
> The winding is not too hard to do, and once you've done one, you'll be
> champing at the bit to do more.
>
> Everybody at the club meeting expressed an interest in getting involved,
> and
> that was most heartening! The immediate problem will be finding the date(s)
> that enough of us can come to do the work. John C Lawson KJ4NGC assures me
> that, given a two-week warning, the Fire Department would allow us to do
> the
> work there, especially if we could come in the morning. By the way, there
> is
> a second-floor meeting room there as well as the one we were in on Monday
> night, so he thinks the chances are very good that we could get a Saturday
> morning of our choice.
>
> I have volunteered to be the one who finds a date which is suitable for
> most
> of us. This will require some action and commitment from each of you who
> wants to be involved in this project. We will first start to ask you to
> check your calendars for the months of December and January.
>
> Check with the important people in your life to see if you can spend some
> quality time starting on a Saturday morning during this 2-month period.
>
> Then email me (carter128 at verizon.net) the Saturdays in that time frame
> that
> you positively can NOT attend.  I will take an accounting, and try to find
> THE Saturday that MOST of us CAN make it. I realize that some people have
> obligations they cannot skip, so there will be no hard feelings if you
> can't
> make the first meeting, as there will probably be one or two more
> get-togethers before the project is successfully completed. We ought to be
> able to find some way you can be involved in this project--and we want you
> ALL to take part, if you possibly can.
>
> Donnie says that he has access to some sophisticated equipment where he
> works, and he has volunteered to do the final tweaking of the filters for
> us, and we thank you for that Donnie.
>
> So, let's get started by sending to me an email with all the Saturdays that
> you absolutely, positively CANNOT attend the first construction meeting at
> the Dublin Fire House. I work best by using a deadline, so let's say to
> write me back by Saturday, December 10th at 12:00 Noon. I hope that will
> give everybody time enough to look over their calendars, to check with
> church and work and home obligations, to check with bosses and managers
> and/or spouses and significant others.
>
> I will get back to everybody on Sunday, December 11th, on the Sunday night
> net at 8:00 PM on the 147.180 repeater. (And if my signal is bad, I will
> email everybody the following day!)
>
> I hope you all will respond as soon as you can. I promise you that this
> will
> be fun, and educational as well!!!
>
> 73,
>
> Carter N3AO
>
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