Tuesday, September 28, 2010

'Stink Bugs' at Portable QRP location

I left the End Fed Antenna up at my mom's house in Lovettsville for a couple of weeks with the lead in coming through a window left cracked open and the room was infested with brown marmorated stink bugs when we came back this time.  There were so many on the curtains I took them down and threw them into the garden, then they all try to get back in!  They will climb on to the coax lead in and walk right back inside.  Finally I gave up and threw the antenna lead out the window and latched it.  No more radio with the window cracked open here!

This Penn State paper offers a good background info http://ento.psu.edu/extension/factsheets/brown-marmorated-stink-bug

There were so many of these creatures it was like a biblical plague.  The vacuum cleaner method seemed to be the best approach to getting them out of the house.  They are resistant to many pesticides and they do give off a mildly offensive odor when they are threatened or die.  We found they liked dark folds in the curtains, crevices in upholstery, behind pictures and mirrors on the walls, and other nice dark easy to get at spaces.  They come indoors in Sept -Oct looking for places to 'winter over'.  For collecting them without a vacuum cleaner, a large tall glass with some soapy water is good.  One of their defense mechanisms seems to be to fall so if you tap the glass on the wall underneath them they often just let go and fall into the glass.  They are good swimmers but the soap kills the surface tension on the water and they will sink and drown.  The best defense seems to be sealing all the cracks around the doors, windows etc.  

Have fun with these creatures!  It is a bit like a bad Sci-Fi movie.  

Thursday, September 23, 2010

QRP End Fed Tuner Kit

A few months ago KI6J mentioned he was going to do a kit of his end fed tuner that he designed for SOTA use and it came last week.  Here are his pix of the kit.  Mine went together this far with no problems and I am looking forward to getting it finished and tested with one of the QRP rigs here.

Parts included in kit

Top Side of board with 3 bridge resistors
My tuner build

Bottom of board with tapped inductor, switch and polyvaricon

KI6J SOTA Station Tuner in upper right of pack, rig is ATS-3

4/4/2011  Still have not actually field tested the tuner however I noticed that Stu said he still had a few of the kits left for $25 shipped.  Contact him at KI6MWN@yahoo.com.

9/2910  Added the 5100 ohm test resistor to the output and tried it with the MFJ 259B set to 40M.  A nice dip was obtained in both switch positions.  With the bridge 'in circuit' the Analyzer read about 1.5 and with it switched out it read about 1.2 to 1.  This was done holding some of the connections and it was somewhat sensitive to hand position.

Schmatic of End Fed Tuner de KI6J

Post taken from AT Sprint Yahoo Group

To all:  here's a link to three pictures related to KI6J's little, teeny, efficient and just down right cute end fed half wave antenna tuner:  

One pic is a snap shot of the antenna analyzer's view for the original prototype version - Stu, KI6J, told me today that improving the parts layoout in Version 2 has reduced the reactive component to nearly zero, but I don't have a copy of that snap shot to share!
One picture shows Version 2 - the tuner and SWR bridge assembled and installed in a small project box - darn cute little thang!!
The last picture shows just the tuner board in the ugly style of construction.
Stu is commiting to produce 100 kits for the EFHW tuner with built in SWR bridge.  He has found a source for all of the components and is working on the PCB artwork now.  He expects to have the kits - tuner and SWR bridge - available by the first week of August 1, and expects the kit to sell at $30 plus shipping.  Note: the board is being designed to fit in the Radio Shack 2x3 inch project box ($3 at radio shack) but the builder will have to provide the enclosure and RF connector of choice.

He also has available, at this time, a few tuner-only boards, already built, like the one in the picture with the quarter for size reference.  Note: this board does not include a SWR indicator but is a ready-to-go end fed half wave tuner for 40 through 15 meters and is priced at $18 per board, plus shipping. You supply an enclosure, connectors and SWR indicator and you are good to go.
Thanks to all that have already contacted Stu and myself, and others interested in this end fed halfwave tuner - it works GREAT! I've got one and find it to be the easiest antenna system to set up, tune and get operate.
Stu's e-mail address is:  ki6mwn@... and you have mine.  Please let Stu and I know of your interest in purchasing one of these sweet 40-15 meter end fed half wave tuners; notifying him/I will make it easier for Stu to plan his off-work hours accordingly and have the tuners ready as close as possible by that first week in August - if that date slips more than a couple of days, Stu or I will notify you individually.  If you have technical questions, address those with Stu.
Please pass on, as appropriate, to other hams you interact with and think might be interested in this tuner and SWR bridge.
Best regards, Jim Rodenkirch, K9JWV
Disclaimer:  I have no financial interest in this endeavor - Stu and I are friends and I appreciate all he's done to get this end fed halfwave system up and running; I, simply, believe in this product, LOVE how it works for me and want to share it with other QRPers!  I, probably, will handle the shipping of the orders for Stu as there is no sales tax for out of state deliveries here in Utah; whatever my shipping costs are to your specific locale will be the cost to you.

Note added Sept 2, '11
Hendricks now has a very similar kit see Hendricks SOTO EFHW

Wednesday, September 15, 2010

Coroplast Gel Cell Cover

2 4.5 AH 6V gel cells 

Primary are over and using a piece of Coroplast I borrowed an idea from Bob AD7BP and made a cover for one of my QRP gel cells and added a Powerpole connector to help prevent shorts and provide a bit of cushion in the pack, go-bag or luggage.

Coroplastic Batt cover

Powerpole Connectors are oriented according to Orange Co. Races info

Tuesday, September 14, 2010

Aural Exciter with Big Bottom

Aphex Aural Exciter

Just added an   Aphex Aural Exciter Type C2 with Big Bottom to the station.  This unit is something I have wanted to try because it is so famous in the recording business.  http://en.wikipedia.org/wiki/Aphex_Systems
These are now available for a reasonable price on eBay and require a mic preamp.  At the present I am using the soundcard as part of the audio chain.

Monday, September 13, 2010

NoVA QRP Sept Get together

Attended the 2nd Annual NoVA QRP Get together last Saturday and took the Willamette20 over for 'show and tell'  We also got to see the host's 'Shack' which is more like a radio mueseum than anything I have seen.  NoVA QRP has now been around for 11 years!

Link to NoVA QRP
Link to some pix on Webshots

Friday, September 3, 2010

Back to the 70's

Drake TR-33c from the late 70's

Received two NOS Comm Spec Tone boards.  They program to only one tone and you use 'solder blobs' to select the tone that you want.  One went in a FT-726 V/UHF All Mode from the early 80's and the other went into the Drake (actually Kenwood-Trio) TR-33c which was an upgrade to the much more famous TR-22 that was probably the 1st really sucessful transistor FM Transceiver for the Amateur Radio Community.  These units helped fuel  the 'repeater craze' that was a forerunner to modern Cell Phone systems.  Now the radio will make a good Emergency Monitor for the local repeater because it draws very little power it will run for days off a small gel cell battery.  35ma on Rx with no signal.  Rig underneath is the home made 20M CW transceiver called the Willamette20.

Comm-Spec Tone Board

This is similar to the tone boards used but this is a newer model with a DIP switch instead of solder blobs for the tone selection and this one will do 64 tones instead of 32.