Friday, March 4, 2016

The N3ZN Iambic CW Paddle

Behold... mechanical beauty 

N3ZN ZN-QRP Iambic Paddle (sporting my new call sign)

I re-entered the amateur radio hobby in the summer of 2015 after a bit of a hiatus.  To get my General license in 1996 a Morse code proficiency test was required.  At that time I had purchased a cheap MFJ practice key and a used version of the ubiquitous Bencher BY-1 paddle.  My Bencher was in reasonable shape but I just never became comfortable with it.  It always felt a bit imprecise to me and I wasn't happy with the width and size of its paddles.

When I came back to the hobby in 2015 as a QRP, CW operator I wanted a key for portable operation so that was my initial focus.  At the time, based on some fellow hams recommendations, I chose the Palm Single key which is an excellent, lightweight key for portable use that travels very easily because it collapses into its own travel case.  However as you can see in the videos in that review it's portable nature tends to make a bit imprecise and wobbly.  It works great for portable use but there are far better choices for a desk key.

I wanted a key suitable as the main station key but also easily travel with to operations where I'd have a desk.  So I didn't want a 4 pound immovable monster.  I wanted something small(ish) but stable and that's a tall order.

I looked at the eham.net reviews for keys and paddles and there were lots of good choices.  I narrowed it down to commercially available keys that allowed some customization.  Begali and American Morse both received favorable  reviews.  American Morse makes nice smaller sized keys and Begali makes works of art.  Both offered good choices but at greatly different prices.

Then I looked at N3ZN Keys.  Tony makes some very functional and attractive keys with a variety of build options.  One such option is the spacing across the outside of paddles (OTO).  My Bencher BY-1 paddles have about a 3/4" OTO spacing on the paddles and I have to consciously hold my hand open a bit wider than it naturally wants to be to keep from accidentally touching a paddle.  Tony offers different OTO spacing down to 1/2" which I found to be about perfect.  I also had a chance to physically try one of his QRP sized keys at my friend AA4XX's station and the light touch and precision feel immediately won me over.

So I went through Tony's online catalog and corresponded with him.  I chose a ZN-QRP style key with a red base.  The red paint contains some metallic bits to make it sparkly under bright light, not bass-boat sparkly but tastefully done.

Tony packs his product for shipment double boxed with more peanuts, bubble wrap, and foam than I have ever seen in any single container before.  The packing is truly amazing.  My key package could have been air-dropped (or drone dropped) onto my front walk and it would have suffered no ill effects.

ZN series iambic keys Specs

  • All stainless steel screws
  • Large 10-56 adjustment screws for both magnetic return and contact points ( the straight key uses 8-32 screws and a spring for return)
  • Ball bearing lever return-3 ball bearings per lever arm
  • Magnet lever return individually adjustable
  • Lightweight aluminum 6061-T6 levers for QRQ operation
  • silver contacts 
  • Wired with 1/8" stereo plug
  • Soft non-skid low profile rubber feet mounted with stainless steel screws
  • 30 Day money back guarantee.  If you are not 100% fully satisfied then return item in its original condition and receive a full refund.  (You pay return shipping)
  • carbon fiber fingerpieces- 3 colors
From the first long QSO it was obvious that I finally had a quality key.  The paddles just disappeared under my fingers and became an extension of my hand.  The lightweight aluminum levers combined with the carbon fiber finger pieces results in such a light touch that I kept wondering if I was actually operating the key.

Photo Gallery

This key is just too pretty not to photograph.

Carbon Fiber Finger Pieces 

Ready for Racing

Metallic Paint on top cap and customizable name plate no extra charge

Metallic paint on base, Aluminum levers and fine pitched adjustment screws
Pre-wired connections
"Houston, We have contact" Stainless Steel contact that is

With Silvered contact points
With the Siblings... QRP indeed!


That's all for now...

So lower your power and raise your expectations

72/73
Richard N4PBQ (soon to be AA4OO)

Sunday, February 28, 2016

The Grand Illusion

Five by Nine... QRP... How can it be?

What does an S-Unit really mean and how can a QRP station sound like a 500w station?

The real gain doesn't come from transmitter watts
I rarely go up to the phone portion of the bands.  Since I started doing QRP and CW last summer I think I've only made two SSB contacts just because my focus has been CW.  But last night I was working on a bench project and tuned the Elecraft KX3 up to the phone portion of 40m for some entertainment.

A station in Rhode Island was testing his amp with a new antenna and was getting reports from various stateside operators.  There was a lull where no one was answering his CQ so I thought I'd give him a call.  He was peaking at S9 on my KX3's meter and he also sent me a signal report of S9 with some 10 over peaks.  I then told him I was a QRP station running 10 watts and heard the usual surprised reaction from a QRO station.

I gave him reports as he switched back and forth from running barefoot ~75w to his amp ~500w.  With his amp on he was an S9, running barefoot he was S8.  So the amp gave him one additional S unit.  In terms of hearing him I would have been hard pressed to tell much difference simply by volume.  He was perfectly copyable without noise with the amp off.

We also did some tests with my station at reduced power (as if...)  At 10w-12w output I received a S9 to S9+10.  Reducing output to 5 watts netted me a S8 report and when I reduced to 1 watt (one watt) he was still able to comfortably copy me and I received an S5.  So with my station at 1 watt and his running 500 watts we could still converse via SSB.  Ladies and Gentlemen you don't need as much output wattage as you think you do.

He was running through a newly constructed homebrewed vertical while I was using my 80m OCF Dipole.  We didn't discuss what sort of radial system he had installed, but the difference in antennas was likely the deciding difference in our stations.  We were about 500 miles apart and his vertical probably had more low-takeoff gain than my dipole, or possibly more ground loss so I probably had better high angle gain on him for the short 500 mile skip.  I think the take-away from this exercise is that the antenna is generally the key rather than transmitter power.  If I can get 6 dB of gain from my antenna I have in essence quadrupled my effective radiated power.  Quadrupled?  Yes, Quadrupled effective output power.

Power and S-Units

You've probably heard it before but it's worth a refresher...  Our radio's meter display a measurement in "S-Unit".  To move the meter up one S-Unit the receiver must hear 6 more dB (decibels).  So one S-Unit is 6 dB.

A decibel is:
  • A Power Ratio:  dB = 10 Log P2/P1
  • A Voltage Ratio:  dB = 20 Log V2/V1 

You increase 3dB each time you DOUBLE your power

That's worth repeating... 
You increase 3dB each time you DOUBLE your power.  So to gain one S-Unit you must quadruple your power.
So if you are running 100 watts, to gain one S-Unit using the same antenna system you must increase your power to 400 watts.  If you are running QRP SSB (10 watts) that is only 1.5 S-Units down from 100 watts.  100w / 2 (-3dB)  = 50w / 2 (another -3dB or 1 S-Unit) = 25w... etc.

Antennas offer the cheapest increase in dB

Note the statement above "using the same antenna system".  That's the key then isn't it?  It's easier to get 6 dB of gain from an antenna than from wattage.  A 40m doublet can offer significant directional gain especially when operated on higher bands.  Now unless it's rotatable you will be at the mercy of the directionality of its lobes but if you have trees or tall structures you can very cheaply string up a few dipoles oriented in different directions and for far less money that a 500 watt amp (6 dB).  If you can only have one wire antenna you may miss out on some DX in the antenna's nulls but you will have some stellar gain in the direction of the lobes.  Of course rotatable yagis and beams are the best but now we are talking about real money again.  I'm talking bang for the penny.  You don't have to buy a wire antenna.  Some Dacron rope or weed-eater line and some surplus insulated wire is all you need.  You can even make your own feedline cheaply from electric fence wire and insulators.

We have a great hobby, but there are so many aspects of it that sound like common sense when they really are not... like increase your power.

Increasing power gains you very little compared to a better antenna systems.

That's all for now.

So lower your power and raise your expectations (or your antennas)

72/73 (Note:  72 is a common substitute for 73 among QRPers... as in "not enough power for 73") 
Richard, N4PBQ

Friday, February 19, 2016

1 Watt and a Wire... in the Attic

You can't always get what you want, but you try sometimes...

Recently I've dialed my normal 5 watts down to 1watt (one watt, singular) for all my contacts.  To throw some water on the fire I've decided to use my attic antenna which weaves all around my metal ductwork and electrical wiring.   Mostly this was to prove a point to myself but it may be enlightening to deed restricted hams that they can use a qrp radio and an attic antenna successfully.

Key lineup... Palm Single (paddle), Vibroplex Bug (circa 1970s), Kent Hand key

It only seems pointless until you try

Calling CQ with 1w QRPp into a poor attic antenna isn't as pointless as it would seem.  I didn't have to wait long when calling CQ before I got an answer most of the time.  

Now am I going to bust a pileup with 1 watt ?  Possibly not but I think that my assumptions about both how much power I need and how big an antenna I need are usually out of proportion with reality.

1 mighty watt

My assumptions are often incorrect

I made QSOs on 30m, 20m, 17m and 10m this morning all at 1 watt.  The solar conditions report was not really fantastic, especially for 10m.  Yet 1 watt through the attic antenna bagged the only DX I heard on 10m.  I had a couple of other multiple exchange contacts on 20m, 17m and one good old fashioned 25 minute long ragchew on 30m where I received a 599 report for my one watt from Bob (NR8M) in Ohio.  Admittedly, Bob was booming in and we had good propagation to each other.

http://www.hamqsl.com/solar.html

Video

The recording below was number 4 or 5 this morning.  I wanted to post this one because I was working another QRP station in Arkansas (K5EDM) and we did NOT have great propagation to each other.  He was running 5w while I was running 1w so it was QRP to QRPp.  In the video you can see that I'm using some of the KX3's tricks to pull the signal up because there was a lot of QSB and noise (note the GEOMAGNETIC FIELD UNSETTLED in the solar report).  

I had the volume maxed and was using the RF gain control mostly.  I eventually had to turn on the preamp which really washed me in noise but I dropped the RF gain more and eventually switched in the APF (audio peaking filter) which performed magic on this contact.  Often I find that APF doesn't help but this time it made a big difference.


That's all for now

So lower your power and raise your expectations

72/73
Richard N4PBQ

Thursday, February 18, 2016

The need for speed in CW

CW QSO speed statistics... 

As I continue on my Morse Code Journey I have been using a desktop application called Morse News to work on my code comprehension of natural language sentences for ragchew training. I set the program to send at speeds higher than I can copy to stretch me.  Presently I have it set at 26wpm character speed and 23wpm Code speed.  I can usually figure out what the news story is talking about but I miss a lot of the specifics.



I was a kid in the 1970s when Speed Racer was a popular cartoon

The need for speed

Currently I'm OK working up to 20wpm qsos as long as the other station has good spacing.  Sometimes I lose the thread or the specifics in a ragchew at 20wpm and I just ask them PSE AGN? 

In sprints I can copy a callsign sent at 25wpm to 30wpm if I hear it a few times but that's no good for real contests where you need to catch that call sent at 30-40wpm sent the first time.  My friend AA4XX has asked me to help him in multi-op contests but I know he is sending around 30wpm and I just can't hang there at this stage in my Morse Code journey.

Statistics show 25wpm is the magic number

So it got me to wondering what was the actual "average" qso speed.  I downloaded days of raw data from Reverse Beacon Network.  RBN collects the call sign, the SNR and the SPEED.  The raw files contained between 40 to 50 thousand CW CQ calls logged each day after I filtered out other modes.

The average speed from RBN CW logs worked out to exactly 25wpm.  The standard deviation was 5.34wpm which would mean most of the time you would expect to work stations between 20wpm and 30wpm.  That seems reasonable and matches what I seem to hear on air.  These numbers are from the CQ calls themselves and are only measuring character spacing speed so the code spacing is likely a bit lower in most cases and for ragchews is likely averaging 2 to 5 wpm lower than the actual sent character speed.  Since I am not much interested in serious contesting at this stage in my hobby going over 30wpm isn't on my radar.  

So based on those calculated CW speed statistics from RBN data if I can reach the point where I am comfortable in a 25wpm ragchew I should be content (for a while)

That's all for now.

So lower your power and raise your speed.... err expectations

72/73
Richard, N4PBQ

Monday, February 15, 2016

Race to the bottom

1 watt or less?

I've been considering ordering a 1 watter kit but I was concerned that it wouldn't be useful in the downward sunspot cycle. 
1Watter board with initial 100nf caps installed and starting inventory of other parts.
Not shown are the myriad toroids (fun, fun), transistors and pots.

So I spent some time this afternoon making 1 watt contacts on 20m and 40m with my Elecraft KX3 just to see what staying limited to that power would be like.  I've made casual 1w contacts in the past but staying at 1watt was a good test for me.

It turned out that I had a plenty of answers to my 1 watt CQ calls and received reports that were only one or two points down from my report to the calling stations.  The last station I worked dropped down to 300 milliwatts and I still copied him fine. 

So I ordered a 1 watter kit for 40m from Kits and Parts today.

The 1 watter kit is significantly more involved to build than the Elecraft kits I've assembled to date. I hope to learn a lot from the build and alignment and I just might finally have a reason to buy an oscilloscope (hopefully my wife doesn't read this).

Update 2/20/2016:
I received the kit yesterday.  It includes 21 100nf SMT capacitors that the builder "highly recommends using".  Optionally he supplies through-hole capacitors.  I tried figuring out hold to hold the SMT part in place to solder for about 30 minutes and gave up.  I don't have 3 hands. I'd have to have someone show me how to solder an SMT part.  Even in the linked video to building the kit the builder used the through hole components so I don't know why the SMTs were supplied or were highly recommended.  So I used the through hole capacitors. 
Through hole versus SMT capacitors

I couldn't figure out how to solder the tiny SMT capacitors
1watter board with the 21 through hole 100nf caps installed

Inventory of resistors
Next step was installing resistors.  There are six 1/8w resistors missing in the kit:
  • R3,9,21,22 (470)
  • R12 (1.2K) 
  • R14 (4R7)


I haven't built enough kits to have spares like this so I sent them a note and will see how long it takes to get the resistors.  I haven't inventoried the rest of the parts yet but so far I'm a bit disappointed.  I have built 4 kits from Elecraft and one from 4-State QRP and all of those kits had all the parts.  Although in the case of 4-State QRP one of the plastic knobs was broken in shipment.  They sent me another in 3 days.

That's all for now. 

So Lower your power and raise your expectations

73/72
Richard,  N4PBQ 

Thursday, February 11, 2016

Skippy 80m

80m QRP 4600 mile skip?

I am still relatively new to operating QRP and operating on 80m. I made a few SKCC contacts last night and had a nice long ragchew with Mark (W1AAF).  When I was shutting down my station I looked at my browser window displaying the Reverse Beacon Network and was surprised to note that my QRP CQ on 80m had being reported by RBN stations in Europe.  The reporting station in Slovenia was over 4600 miles from me! 

I have not seen 80m skip like this from my station so this was new to me.  I have made some cross continental contacts on 80m but never seen it go 4600 miles to the Northeast before. I'm used to that from the higher bands but not my NVIS 80m antenna.

80m Skipping up to 4600 miles

Antenna patterns

This got me to thinking about my 80m OCF Dipole which has been a good performer for me especially to the North and West but generally poor to the South.  However a couple RBN reports also showed my signal as strong as 22db to Puerto Rico and Curacao last night so some sort of 80m propagation pixie dust was being spread around.

Below is a satellite view of my QTH with the layout of my OCF Dipole shown in blue and the direction of propagation to the Wales and Spanish stations super-imposed.

Antenna and propagation
My OCF Dipole is not straight across.  It is bent about 25 degrees as you can see due to my anchor points.  The long end slopes down to about 10 ft above ground while the apex is only at 25 ft tied off to the peak of my roof. The short leg heads off level to a tree in the front yard.  So 25 feet sloping down to 10 feet is certainly not an ideal height for 80m so the take-off necessary for the skip to the distant European stations is very surprising to me. 

Too good to be true?

This antenna has been a good NVIS antenna for me on 80m and a relatively good DX antenna given the recent poor band conditions on 17m and 15m.  Even though I normally operate QRP or sometimes up to 10 watts I nearly always get a signal report that is either equal to or only one S-unit lower than the QRO stations I qso with. I have really been puzzling over this antenna lately trying to figure out why its SWR is so low on so many bands.  It shouldn't be this good.  And if something seems too good to be true it usually is.  Low SWR doesn't always mean antenna efficiency.  When I measure the individual sections of coax connected to this antenna they have SWR and reactance issues.  I still use an old run of coax that comes back into the house that has problems due to a previous lightning surge that was strong enough to melt the solder connections in my spark arrestor so I know things are amiss.  Yet overall SWR, impedance and reactance through all the components connected together is very low on most bands.  The key seems to be my station ground that is nearly resonant on 20m and runs around my house and up to the 3rd story operating position.  The long electrical ground has certainly become "part" of the antenna system, yet I'd expect it to introduce a lot of loss as it ties into 3 ground rods.

But it's nights like this that keep me from "fixing" it.

These sort of mysteries are part of what keeps the hobby interesting for me...
EDIT: August 2016
I did finally replace the coax run back into the house as it turned out that coax braid was damaged.  The result was that my Windom was no longer 1:1 SWR and showed more expected SWR readings.  It's still 1.7 SWR or lower on all the bands except 10m and 6m where it's SWR is 2:1.  So that's likely a more normal response.  The antenna is also quieter now with the replaced coax so all is well.

That's all for now.

So lower your power and raise your expectations

72/73

Richard, N4PBQ

Tuesday, February 9, 2016

Feeling Extra Hammy

I Passed my Extra Exam

I finally took the time to study for the Extra ticket.  The fine Central Carolina VE team administered the exam and did a very professional job for the group of 8 folks taking their tests last Sunday.

Study Guides

I purchased a well done study guide from http://www.kb6nu.com and used QRZ resources page to take practice exams to prepare for the test.  The Extra test has 50 questions compared to the 35 in the Tech and General and draws from a question pool of over 700 questions.  If you have a background in electronics you will need less study than if you do not.  I am a new student of electronics and the process of studying for the exam was very enlightening.

Why go to the effort?

If you are already licensed as a General class you may not see the need for it as it only gives you a bit more spectrum use on some of the bands but if you really want to chase DX the extra (pun intended) spectrum will come in handy.  But I'd recommend studying for it just for the exposure to concepts you may not have explored and more importantly it will allow you to give back to the hobby some if you pursue becoming a VE.  You can be a VE as a General but you are limited in which tests you can administer so most VE teams want Extra class license holders.  I plan to pursue my VE certification after my ticket shows up in the FCC database.

That's all for now

So lower your power and raise your expectations

72/73

Richard, N4PBQ/AE