Tuesday, December 29, 2015

Finer than a frog's hair split twice

Elecraft AF-1 Audio Filter Kit

I've been working a lot of SKCC CW stations during the holidays and adjacent stations really interfere with my ability to use the vintage Ten-Tec Century/21.  Its built-in audio filter is relatively effective if the band isn't too crowded but if I'm working a station and others pop up within a 1kHz on either side I have a real hard time keeping track of which QSO to listen to.  I wanted some relief from the relatively porous audio filtering provided by the old girl.

A kit from Elecraft seemed to be the ticket to better signal isolation for my old radio.

Elecraft AF-1 Audio Filter Kit

Building the kit

This kit is about $60 and is pretty easy to build  There are a couple of ICs to solder so it will be easier if you have a temperature controlled, fine tipped soldering iron. Santa brought me a nice soldering iron for Christmas so this was my first chance to make some use of it. Everything about the kit is very straightforward and Elecraft has wonderful build instructions along with a well laid out board. Their instructions list components in the order that you will be installing them on the board, left to right and even include the color coding or numbering for resistors and capacitors right there in the instructions so you don't have to keep going back to look up the coding.  I've only built one other kit previously and the Elecraft instructions are better.

My only gripe is that this kit has been out for quite some time, but for some reason they shipped me a Version "A" board that required a trace to be cut and a couple of jumpers installed to correct a board error.  I would hope that they would ship new versions of the board but apparently you can get an old version.  Next time I order a kit from them I may specify that I want the latest revision of the kit.

Performance

The board powered up and worked right as the last of the solder smoke was wafting away.  I connected it to the Ten-Tec and tried to find some adjacent station operations to test against but the bands were not terribly busy tonight. I did manage to get a decent audio test on a calling station and created a video to demonstrate the board's capabilities.


Summary

This is the first kit I've built from Elecraft.  It was a simple one.  The instructions were excellent, the silkscreen layout on the board was straightforward and all the parts were in the bag.  The kit does not come with an enclosure so it looks a bit unfinished and the knobs are a bit wobbly on their tall, plastic shafts.  That is my only negative concern regarding the finished kit.  Putting it in an enclosure would also require the battery holder to be moved to the bottom of the board to clear the shafts exiting the top of an enclosure.  Certainly not a big deal but I would be willing to pay an extra $10 for a ready made enclosure because when I've tried to make them they look like junk.

But the bottom line is that if you have an older radio that lacks good filtering or you've built a homebrew radio that you want to be more usable on the air, the Elecraft AF-1 is an excellent addition.  I think it is going to serve me well with my vintage radio.  Now to find a project box to fit it.





That's all for now

So lower your power and raise your expectations

73/72

Richard, N4PBQ

Sunday, December 20, 2015

Which antenna is better?

Real world antenna comparisons

I don't have many choices for my antenna at my residential QTH.  I have an 80m OCF Dipole (aka Windom) hung from the peak of my roof at about 25ft and a ladder line fed 40m Doublet folded around in my attic at about the same height.

Generally I've been using my 80m Windom for most contacts because it is resonant on 7 bands and I don't have to tune it.  I've had a number of on-air ragchews where I switch antennas and ask for signal reports but it is often a hassle and I don't like to interrupt a ragchew to ask for that sort of comparison. 

So how do I know which antenna is better for certain bands and directions?

The RBN

The Reverse Beacon Network offers an objective and patient antenna tester.  I just recently learned about this resource and it's a fabulous tool.  When my CQ isn't being answered I'll often bring up the RBN and check my signal reports and then switch antennas to see how they compare.

It has been very interesting to learn that the Doublet in the attic often outperforms my Windom usually by 12db and sometimes by as much as 20db especially on the higher bands.  I'm guessing that part of it is the greater efficiency in the ladder line but that doesn't tell the whole story because the Windom offers a low SWR on most bands and shouldn't be eating up much power in the coax through SWR losses.  Antennas are magic.
Two highlighted records show the difference when I switched antennas and moved the transmit frequency slightly to cause a new report to be sent

Process

Ok so here's what I do... The RBN stations will report only when they see a new frequency or it's been 15 minutes since the last report for a given station, so when I switch antennas I will move frequency slightly to trigger the new report.  Now admittedly QSB or other conditions may change between the reports so you'll need to do this a bunch of times over the course of days and compile some records to get a clear idea of how each antenna is performing in certain directions.  This isn't hard science but it's more real-world than a smith chart or the occasional signal report from a station or two.

If you make use of the RBN I encourage you to donate on their site.

That's all for now...


So lower your power and raise your expectations

72/73

Richard N4PBQ

Saturday, December 19, 2015

Vertical Space

Taking my station to new heights

My burgeoning QRP station was getting messy, having stuff strewn all over the desk, so I made a shelf from some junk laying around to give me some vertical space. It is much more organized now.
A shelf helps
Left to right top shelf:
Ozark Patrol Regen Receiver Kit, MFJ Versa Tuner providing both tuning and antenna switching duties, Two Position Rig switch on top (blue box), Ham Keyer (circa '78) electronic keyer

Left to right under shelf:
Yaesu HT connected to home-brew J-Pole in attic, two switching power supplies, VHF/UHF meter, Elecraft KX3, Ten-Tec Century/21 (circa '77), Homebrew frequency counter on top of TT)

Three keys:
Bencher paddles, Vibroplex Bug, Kent Hand Key
That's all for now.

So lower your power and raise your expectations

73/72
Richard N4PBQ

Sunday, December 13, 2015

QRP fun and games in the December SKCC WES

Sprinting with a Straight Key - QRP Style

So far in my CW/QRP trek I had not entered a contest nor tried to work so-called "sprints" other than making a few casual contacts.  My copy skills and knowledge of what was going on just was not up to the task.  But after getting my SKCC Centurion certificate last week I was motivated to accelerate my timeline for making the SKCC Tribune level and for that I needed 50 new Centurion contacts.  This weekend was the December SKCC WES (weekend sprintathon) and I determined to make an effort to see how this sprint stuff worked.

I operated 5 watts QRP and used my Vibroplex Bug for most contacts but switched to my Kent Straight key for stations that were sending slower than 13 wpm.

SKCC operators only use manual keys; straight keys, bugs and cooties during SKCC contacts.  So, in general, the operating speed is quite sedate compared to other sprints or contests.  I'd guess most exchanges were below 20 wpm.  That is a good thing for a new CW operator.  The flip side to that is that the operators are all using manual keys and thus the precision of the Morse Code that would be lent by an electronic keyer is let's say, missing.  While most stations I worked had great sounding FISTs I was challenged on a few occasions to copy some very non-standard sounding code so, as they say; YMMV.

For the most part I called CQ rather than tuning around for contacts. There were a few times where multiple stations answered at once and I admit that I couldn't make heads or tales of what I heard and just sent AGN? until I could hear part of one call separated from the others.  I have a greater respect now for contest operators who can pick a call out of the cacophony of multiple stations calling on the same frequency.

My "Weekend" Sprintathon was actually only 3 hours

I only had the opportunity to operate for about 45 minutes Saturday morning when there were a lot of stations looking for contacts, then I had to break until around noon and the bands were not as lively.  I then had another break until late afternoon before I had a Christmas party to attend, so in total I only had about 3 hours.   The WES is actually still running but you can only operate for 24 hours of the 36 hour sprint so my 24 hour window is over.

In my 3 hours had a rather poor showing of 41 contacts but I recognize that if I could have operated longer during the morning and some Saturday evening I certainly could have logged more contacts.  Nonetheless, it was a good experience.  I realize I need to work on copying call signs.  I'm used to listening to them at least a couple of times to copy them but often in a sprint or contest they are only sent once so you need to be listening carefully.   After maybe a dozen more such sprints I might think about entering an actual contest.

Log Snippet

SKCC Logger

Summary

My goal was to get 50 new Centurion contacts but as you can see from my log summary above there were only 3 "Cs" logged.  Centurions appear to be the rarest of the breed so getting to Tribune is going to take longer than I thought.

Correction: I was contacted by a couple of SKCC members to tell me that any new contacts since my Centurion award with Cs, Ts or Ss count toward the Tribune.  Also they told me the 24 hours is operating time rather than a window... so I should have hung in there but I already submitted my log so I'll know better next month.

So if you are a new(ish) CW operator and want a low stress, slow speed introduction to a contest "type" event,  I can highly recommend the SKCC WES.  I think it's also ideal for QRP operators because these don't seem to be zillowatt station operators or big-gun contester types working these events and your modest power should be sufficient.  One suggestion is that if you're calling CQ rather than chasing stations you will only be getting called by stations who can hear you well enough to copy and likely their signal to you will be better than yours to them so that makes it even easier.

That's all for now

So lower your power and raise your expectations

73/72 
Richard N4PBQ

Tuesday, December 8, 2015

SKCC Centurion Achievement

I set forth my hand on key...

Only manual keys like straight keys and bugs count on SKCC contacts

I joined the SKCC when I started operating CW in late August this year.

SKCC is an abbreviation for "Straight Key Century Club" (not to be confused with "Silent Key Century Club").  
SKCC is an organization similar to FISTS, dedicated to promoting Morse Code / CW operations, but in particular, fostering the continued use of manual keys (straight keys, bugs and side-swipers) because of the historical significance of manual keys in Morse Code.  The SKCC group has some nice tools on their website for looking up member information as well as a special link to the K3UK Sked site so that you can arrange a QSO whenever you like.  You don't have to call CQ till you're blue in the knuckles, just post your frequency to the Sked page and within a couple of minutes you'll likely be in a QSO... the only caveat is  you should be using a manual key (no electronic keyer).

Awards and activities

SKCC members are an active and chatty group of operators who exchange their member numbers even when not in a contest.   They offer a number of achievement awards; some awards are for logging contacts with active SKCC members over time.  The first achievement level is the Centurion Achievement which is given for 100 unique SKCC member contacts.  I hadn't been keeping close track of my count of unique SKCC contacts but I figured I likely had over a 100 unique. I finally went through my log and found that I had over 150 unique SKCC contacts since I became a SKCC member.  So I submitted my log to the SKCC and within a couple of hours it was verified and I received this amusing notification via email of my achievement:
Hear Ye! Hear Ye! Gather 'round and pay heed to the news of this day !

Let there be celebration to recognize a fellow SKCC member who has advanced to the Centurion level of SKCC achievement !!!

Having submitted a log and sworn statement, documenting the completion of QSOs with 100 other SKCC members, Richard Carpenter, N4PBQ, SKCC #14276, is duly proclaimed to be SKCC Centurion Number 1261 effective at 0000Z on 9 Dec 2015. SKCC Centurions are encouraged to proclaim their accomplishment by appending a C to their SKCC Number.

The Master Centurion List has been duly scribed where all SKCC Members may reflect upon and pay tribute to this momentous achievement.

Duly approved, recorded, and published.

I set forth my hand and key.

8 Dec 2015

Ron Bower, AC2C
SKCC 2748S
SKCC Centurion Administrator
As a new CW operator little things like this are nice incentives to keep moving forward with my on-air activities.  This isn't contesting but I feel like I am achieving something as I reach little milestones.

Update 12-19-2015

Well going from Centurion to Tribune is pretty easy when you spend some time in the weekend sprint.  My Tribune level was confirmed today, but going from Tribune to Senator is quite a long road so I expect it to take more than 11 days haha.
That's all for now

So lower your power and raise your expectations

72/73

Richard N4PBQ

Saturday, December 5, 2015

Junkbox eardrum saver

Volume control for my volume control

So my lovely 1977 Ten-Tec Century/21 transceiver has not-so-lovely CW sidetone.  The sidetone has a pronounced thump or pop on the first key-down of each letter. When listening through the external speaker it's not too noticeable but when wearing headphones it becomes really obnoxious and even painful during a long ragchew.

There is a variable resistor on the C21's audio board for the side-tone but it doesn't eliminate the pop, in fact it makes it more pronounced as the sidetone volume is reduced and it is least pronounced when the volume is increased but then the sidetone is really, really loud, especially when using headphones.

Besides that, the headphone AF output is quite hot anyway even at the lowest AF level with my comfy Sennheiser headphones so I figured I could benefit from an in-line volume control.  

I looked at ordering one but I've used in-line volume controls built-into headphones before and they always seem to go bad within a year so I scrounged around in my junkbox and found some variable resistors and volume pots.  I tested them and found one that goes from 10 ohm - 475 ohm so it seemed to fit the bill.  I fished around some more and found a 1970s era Switchcraft 1/4" phono plug and some more old lamp cord and I was in business.

I used the end cap from an old USB thumb drive to lend some mechanical strength to the attachment of the variable resistor to the cord.  Wallah, in-line volume control with a hip see-through enclosure.

Junkbox, in-line headphone volume control
It works great.  Now I can tone down the killer sidetone audio at the headphone jack from my old beauty and as a bonus, the old Switchcraft plug is a historical match for the C21. The variable resistor let's me tailor it to my ear fatigue.  I know this is a simple little 5 minute project but sometimes those are the ones that you appreciate the most.

Free in-line volume control
might buy me a couple of months of hearing in the future
That's all for now.

So lower your volume and raise your hearing longevity

73/72
Richard - N4PBQ

Wednesday, December 2, 2015

Can anybody hear me

Calling QRP CQ - Inconceivable


My 80m OCF Dipole has been a surprisingly good antenna and I've made contacts with it on all bands except 6m and 160m.  Based on my past experience trying to tune up short antennas on 160m I really hadn't considered trying to use this Windom for 160m.  But through some email exchanges with another ham in Illinois who had recently put up a 160m antenna we decided to try a scheduled QSO on the top band.  So it was time to give the Windom a shot on 160m.

Amazingly my 80m Windom / OCF Dipole has  4.5:1 SWR native around 1.8 mHz and it matches easily with a tuner across the entire 160m band.  That was a surprise. 

I tossed my mighty 5 watts call out at 1810 kHz not expecting much...

Within a minute of calling CQ I had a faint QRP station from Maine tried to work me.  After about 4 tries I finally copied his call correctly but then lost him.  Immediately another station called me and we exchanged the niceties of signal reports, location, rigs and weather.  I received a nice 579 report for my 5w and I gave him a 599+ report for his thundering kilowatt station.  He needed to work my County so I was glad to be able to provide him with the contact.  Following that call the former QRP station from Maine was back in there and finally we worked each other.  We had a nice QRP to QRP QSO on the top band.  He gave me a 549 report but he was using a 400 ft beverage receive antenna.  I was struggling a bit more to copy him through local QRM on my side and a less qualified receive antenna and reported his signal as 339.

Those were my first two contacts on 160m using CW.  Who'd have thought my cloud burner antenna and QRP power would get me such quick results on the top band.  I just figured no one would hear me.  
So how do you know if and where your signal is getting out ?

The Reverse Beacon Network

I had to quit right after those two QSOs but when I later checked my email the original station with whom I'd planned the scheduled QSO reported that although he had not heard me he said I was getting out and sent me a link to something called the reverse beacon net showing a couple of stations that were hearing me on 1810 kHz.

You mean I can find out in near realtime if and where my signal is being heard by an automated system? No way!  That is cooler than a Ronco Pocket Fisherman.  Recall that I'm relatively new at this stuff and this may be old hat for a lot of you.  But the ability to toss out your call and in real-time check where your signal is getting to just warms the push-pull final transistor in my heart.

The Reverse Beacon Network can give you the last 100 reports of your station. So I took a look and saw some of my weekend activity where I was shooting some fish in a barrel (I mean working contest stations) and there were beacon reports of my call from such places as far South as the Antilles and as far West as Utah.
Map of the last 100 reports from Reverse Beacon stations of my call sign
Color coded by band

So the reverse beacon network report tells you what station heard you, the frequency, the signal to noise ratio (higher is better) and your word per minute (wpm) speed.  

It even includes a speedometer

Being a new CW dude my word per minute speed is of interest to me.  Most of my QSOs in the past week have been at 15-16 wpm.  I'm using a Vibroplex Bug I received last weekend and have slowed it down with a home-made weight attached to a drywall anchor pressed on the end of the pendulum.  I found it interesting that some beacon stations reported me at 19-23 wpm.  I looked at the time and the frequency and realized that the higher speed was from my first on-air QSO using the Vibroplex Bug with N4HAY before I slowed it down with my junk box bug tamer.  
My brief speed key session with N4HAY
So if you are using a manual key and don't know what speed you are sending just check out a beacon to see what speed they are reporting.

Summary

This reverse beacon stuff has been around a while. So unless you're a newbie like me you probably already knew about it.  But if you haven't used before it's very cool, especially with regard to knowing how your QRP station is being heard. Are you making it 1000 mile per watt?  Is your antenna propagating East, West, North or South.  How and where is the skip?  This answers many questions that I had been wondering about as I'm operating.  A shiny new toy, just in time for Christmas

So that's all for now.

So lower your power and raise your expectations

73/72
Richard N4PBQ