BLT+ Tuner portable Test

A shot in the dark

I wanted to test the BLT+ Tuner portable with a ladder line fed Doublet but my time has been limited.  After getting home from work one night I assembled a 40m Doublet fed by 450 Ohm ladder line in my driveway.

I pushed the Doublet up on my Jacktite pole and attached the ladder line to the BLT+ and attached the BLT to the KX3.  I had the KX3 sitting on the deck table running on internal batteries.

BLT+ tuning the balanced line antenna

By the time I began my test it was quite dark except for the moon.  My headlamp was out of batteries and I was operating by a floodlight up on the eve but I was determined to know how the tuner worked with my portable doublet.

Doublet on Push up pole.  Moon in the background.

40m and 30m tuned up 1.0:1 using the high capacitance setting.  Tuning was fast for each band using the SWR indicator LED.  After tuning on 7030 and sending my call then again on 10110, I tried 14060. Although tuning 14m was a bit touchy it tuned using the low capacitance setting to around 1.5:1 SWR.  After tuning I sent my call on 20m.  Immediately I received a call from K7JHM, a QRP station in Utah (about 1700 miles away).  We exchanged signal reports and station information although copy was a bit rough.  I'd neglected to bring my earbuds out and the speaker on the KX3 is pretty poor.

However, the QRP to contact was a success on a portable antenna, tuned with the BLT+ driven by a rig running on internal double A batteries. 

I didn't try higher bands because it was so late in the evening so I packed it all up declaring success.

Balanced line tuner doing it's job

Tuning 20m was a bit touchy because my total length of one leg of the doublet plus the feedline is too near a 1/2 wavelength on 20m.  I need to add about 7 feet of ladderline to keep it from being near odd 1/8 wavelengths of the bands I want to tune. Or I could add 7 feet to each leg of the antenna.  I will need to do that before the next test.

That's all for now

So lower your power and raise your expectations

72/73

Rich AA4OO

A visit with a QRP contest station

160m Spring Stew Perry Contest - QRP style

I had the opportunity to visit with Paul Stroud AA4XX as he worked the early hours in the 160m Spring Stew Perry Contest.  Paul is an avid CW operator dedicated to QRP and QRPp operations.   When he works contests he often participates using the Knightlites club call WQ4RP (Note the QRP in the call).

AA4XX operating as WQ4RP during the 160m Stew Perry Spring Top Band contest

160m Top Band

160m (top band) is challenging due to the physical logistics of a suitable antenna.  I had the opportunity to assist with a portion of raising the 160m vertical loop antenna at the "Excalibur antenna site" and installing the 24 elevated radials that help make this antenna so effective.  There's a lot of wire in the ground system.  The antenna site is located in the woods, off grid, and away from electrically noisy homes.  

Power to the remote shack is supplied by a quiet Honda 1kW generator operating a couple dozen feet from the shack.  Due to the lower power requirements of QRP Paul can run the generator on eco-mode allowing its small fuel tank to provide 8 hours of operation between fill-ups.

Paul uses a Ten Tec Argonaut VI, running 5 watts output into the Excalibur 160m vertical loop.  He uses N1MM+ logger software and a WinKeyer interfaced to the software.  He also employs a SDR (software defined radio) feeding CWSkimmer signals across the band.  An antenna splitter simultaneously feeds the SDR and the Argonaut. The SDR receiver is switched out during transmit by a DX Engineering RTR-1A Receive switch.  His CW key is a N3ZN ZN-QRP model.

The N1MM+ logging software keeps track of which stations have already been worked and the CWSkimmer interface displays calling stations on the band being heard by his antenna.

The remote QRP station setup for contesting

In the Stew Perry contest the only information exchanged was grid squares.  I'm still relatively new to CW and watching Paul casually copy grid squares sent at 30wpm was impressive.  I would have had to ask the caller to re-send their grid squares 5 times but Paul makes it look easy.

Instructions for the newbie

Paul explained to me the in's and out's of operating in a contest.  Speed and timing the openings were important, as was persistence. The integration of the software and receiving tools optimized his operating but experience and skill seems to be the biggest factors to success.  I could have sat down there using the same tools but I would have been dumfounded with the logging controls and the speed the other stations were sending information.  However, not all stations were sending at mach speed.  When Paul worked a station sending at a slower or faster speed he would use the interface to Winkeyer to speed up or slow down the sending simply using the Page-up / Page-down keys.  He would change frequency to a new station in the skimmer display by clicking on it.

Due to the limited amount of information exchanged during the contest most of the sending is accomplished via macros programmed into the contesting software.  Paul rarely had to touch the CW key during the time I was there and his primary physical interaction with the radio seemed to be changing bandwidth or bandpass settings (he tends to keep bandwidth at 500Hz).  

Paul demonstrating the contesting software and usage

Why QRP?

This contest was not a QRP-only contest although there were multipliers for working QRP.  There were plenty of big gun stations operating and the Reverse Beacon spots showed some of them with 56dB SNR reports pounding the ionosphere with their big amps.  

The strongest signal spot  last night for WQ4RP was 35db with the average at around 18dB.  Paul has worked QRO in the past but the challenge of QRP operation is now in his blood.  During a previous 160m CW contest this winter he and Dick Hayter N4HAY worked 3 stations in Hawaii with Excalibur which thrilled them given the current propagation on 160m.  QRP adds a bit more challenge and those multi-thousand mile per watt contacts on the top band make it all the more special

Finding the next station to work. (N3ZN QRP CW key in the foreground)

Why contest?

As a new CW operator I'm still getting my feet wet and enjoying the process of improving my CW copy skills doing more ragchews than adding stations to the log or chasing DX.  I casually contest with the SKCC weekend sprints and it can be fun to see how many stations I work but I'm not ready for real contesting.

During the time I observed, I could sense Paul's excitement seeing the propagation progress across the band and when a distant station in Russia was heard he looked forward to the challenge to getting that one in the log using QRP.  He let the stations running big amps get their fill before jumping in.  Ultimately he wasn't able to work that station but he later worked a GW3 station in Wales which was a first for him on 160m.  The rewards of contesting seem to be in the accomplishment of something difficult and achieving something new.  I can understand that.

What's next?

With summer coming on 160m will turn noisy from atmospheric static and the opportunities for top band contacts fewer.  Attention will turn to other bands and challenges for a while.  Maybe Paul will decide it's time to get that 40m Moxon back up on the tower as the sunspot cycle decreases this summer.

I enjoyed the opportunity to watch real CW contesting first hand.  It is technically challenging and requires skills I do not yet possess and I look forward to progressing in my CW/QRP journey to the point where I can assist Paul in a contest.

That's all for now

So lower your power and raise your expectations

73/72 

Richard, AA400

I will have a BLT please

The BLT-Plus Balanced line QRP tuner

I was looking for a QRP tuner for the 1Watter 40m transceiver I am building that would work with both balanced feedline antennas as well as coax feedline.  The traditional Z-Match tuner is quite efficient at tuning balanced line antennas and the built-in SWR bridge gives you an all-in-one tuner and SWR indicator without having to take a separate SWR meter along with its inherent mess of cabling a separate SWR meter.  The BLT in the name stands for "Balanced Line Tuner".

This tuner kit is available from the fine folks at Pacific Antenna. 

The Kit as it comes out of the bag

The kit comes with everything you need except for hookup wire and your soldering equipment. Instructions are downloaded from the qrpkits website.

Why use a z-match ?

Here are some advantages that the Z-match design offers:

• Matches balanced loads without the use of lossy baluns.
• Being a parallel resonant circuit, the Z-match can provide some band-pass filtering for your receiver and harmonic attenuation for your transmitter.
• A well-designed Z-match tuner has a high Q and is more efficient (less lossy) than other types of tuners.
• The fixed inductor simplifies construction (no taps or rollers needed).

The secret sauce

Matching balanced line fed antennas is sometimes problematic for a traditional balun and tuner as the antenna can present impedances that are far outside of the balun's design.  The Z-Match uses a center tapped coil to keep the complex impedance balanced across the inductor (at least that's how I understand it).  I have measured my Elecraft BL2 balun getting appreciably warm at QRP levels when connected to my doublet indicating loss I'd prefer to avoid.  The Z-Match design supposedly results in less loss.

Built in SWR indicator

The BLT plus includes a Dan Tayloe N7VE LED SWR indicator which eliminates the need to carry a separate SWR meter.  The concept is beautiful. The SWR bridge is switched into "Tune" mode and presents a 50 Ohm impedance to your transmitter while you are tuning so that you don't risk damaging sensitive home-brew finals.  The LED lights when the SWR is too high and dims and then goes out as the match is made.  It is simple and fast to use.   The instructions for the bridge are not with the BLT instructions. Download them from this link.

SWR bridge with LED indicator

Switch to Tune to present a low SWR to the transmitter while matching, switch to Operate when finished

Building

The kit is relatively easy to build with one tapped toroid to wind for the SWR bridge and one 3 winding toroid for the tuner.  I faced a few issues that you might avoid:

• The kit is provided with really nice water slide decals that give it a commercial look (if you don't ruin them like I did).  The instructions recommend applying a clear coat to the decals after they are applied.  I used a Krylon matte finish clear coat which indicated it was fine for metals and plastics but it partially melted the decals and caused them to bubble.  I'd suggest testing whatever you are going to clear coat them with first.
• Don't over tighten the plastic tuner shafts or you won't be able to slide the knobs on (yes I did).
• The binding posts have little plastic spacers that separate and it isn't obvious.  If you install them and wonder how they don't ground themselves (like I did) you've done it wrong and will have to go back after it's together and try to remove them with all the wiring in place.
• The bolts for the binding posts are very soft metal and the nuts can strip them if you apply too much force (yep I did that too).
• The main toroid has three sets of windings and they overlap.  Pay attention to the instructions about winding them all in the same manner (clockwise or counter clockwise) or you will have to rewind them (yep, I did that too).
• The 3 windings on the main toroid overlap so you won't be able to go back and verify your turns when doing the 2nd and 3rd winding so count carefully (ask me how I know).
• Temporarily attach the SWR bridge to the front panel to get the spacing correct to solder the LED leads.

The SWR bridge instructions are separate from the kit instructions and simply googling them will give you instructions for an older version.  Use the version here.

My tuner toroid ended up being a bit messier than I'd like because I had to rewind it and my resulting leads aren't as short as they could be.  I may go back and trim the leads to make it tidier but my least favorite part of winding toroids is heat stripping the insulated magnet wire so I'll probably leave it as is.  Initial tests indicate it's working great.

My messy toroid winding... but it's working fine

Operation

1. Connect your transmitter and antenna.  
2. Choose the appropriate switch in the back for coax or balanced line antenna (Up for coax, Down for balanced line).
3. Start with the inductance switch on the back set to low-impedance (Low-Z) because it is the most efficient.  It uses the 6 turn secondary rather than the 12.
4. Switch the front switch to "Tune"
5. Key the transmitter and be sure you are using 5 watts or less
6. Turn the "Load" knob first until you see a dimming of the LED then the "Tune" knob to make it go out completely
7. The knobs interact so you'll need to go back and forth between them to achieve best match
8. If you can't get a good match switch the inductance switch on the back to "High Z" and try again
9. Don't apply power too long at a time during tune because the 50 Ohm resistors are heating up in there during the Tune process
10. When the LED goes out or gets very dim you have a very good match. Switch to "Operate" and enjoy a well matched antenna

Photos

Result of having to rewind the secondaries made it messier than I'd like

Dimensions

Remarks

Qrpkits offers a great little kit that results in a commercial looking product. You end up with a small portable tuner plus SWR indicator that reduces the complexity of your portable operation.  Pacific Antenna is very responsive to questions. I sent a question concerning the incorrect instructions I'd downloaded for the antenna bridge and James answered me the same day with a different link (included above).

So if you have a QRP radio that needs an antenna tuner I recommend this kit. It's well thought out and works well.

That's all for now

So lower your power and raise your expectations

72/73

Richard, AA4OO

The Spotless Callsign

Invisible Callsign Mystery

I'm a proponent for using the Reverse Beacon Network to determine how your QRP signal is getting out and for comparing different power levels and antennas. I look at how I'm propagating to reverse beacon stations and what signal strength was reported to know whether I should raise or lower power and whether one antenna is favoring another in a particular skip.

But after getting my new call on March 5th this year I didn't see any spots for my call on any bands. I knew my signal was getting out because I was easily working other stations.

I thought the lack of a spot might be due to my new call not yet being updated in QRZ, but even on the following day after QRZ had the FCC update I still had no spots in RBN.  I sent an email to the RBN administrator to ask if there was a filter or database that they used to prevent busted call signs that needed an update for new calls and they said there was not.  They told me if the RBN skimmer station saw the call it would be reported.  However looking at the aggregator configuration information in RBN there are a number of ways to configure filters but these are set on a station by station basis.  For instance a filter for known bad call signs is in there as well as an option filtering against the Super Check Partial Database which is a file containing the call-signs of active contestors. I'm not familiar with how a call-sign get's placed in that database but neither my previous or current callsign are in there.  So it appeared that there was no reason that I should be getting filtered from dozens of RBN stations that normally report my call.

Assistance from CWSkimmer creator VE3NEA

I then surmised that possibly there was some oddity about the CW Skimmer algorithm.  Being the inquisitive type I sent an email to the creator of CWSkimmer (VE3NEA).   He couldn't think of a reason that the skimmer wouldn't copy my call.  In fact, he said it should be easier for it to copy the dual letter calls than others. So we scheduled a CQ test where he specifically looked at the frequency I was sending my call on to see if CWSkimmer copied.   His station is about 570 miles from me so that's a good one-hop distance for 40m.  He reported that the skimmer saw my call and correctly copied it.  He sent me screenshots from his skimmer results.

See the text copied by the skimmer and the identified callsign in the right hand pane

AA4OO shows up in the cluster spot list

However, he noted that although the signal was clear and copied by the skimmer, there were no spots reported on RBN.  He concurred that it was strange and suggested we setup another test where he could watch what the RBN aggregator did with the call once it was passed on by CWSkimmer.

Hurrah, RBN has stopped throwing my call in the bit-bucket

Before I could schedule the followup CQ test with him, I was sending CQ on 80m.  The Reverse Beacon Network spotted me 11 times.  I tried a couple of other frequencies and power levels and sure enough RBN was once more showing spots for my station.

Hurrah, RBN has stopped throwing my call in the bit-bucket

80m propagation reports from RBN this morning

Spots from US, Canada and Europe (40m)... so I'm being spotted again

Still a mystery

So AA4OO is no longer invisible to the RBN but I'm no closer to understanding why the call didn't show up previously.  The lesson here (if there is one) is that if you have become invisible to the RBN don't assume your feedline has been cut by your XYL whilst trimming the hedge (this happened to me years ago) but rather some technical glitch has occurred or you've been blacklisted for being a LID, or aliens are sucking your CQ out of the ether.  In any event, it seems to self-correct so no-worries.  Keep calm and carry on.

Another lesson learned here was that other hams are extremely willing to help.  I think we have one of the best hobbies in the world because of the people involved.  So give back more than you take and you will make the hobby even better.

That's all for now

So lower your power and raise your expectations (and be patient)

72
Richard, AA4OO

Too Vain for N4PBQ

Just call me AA4OO

N4PBQ is now AA4OO

After getting my upgrade to Extra I wanted to get a new shortened call sign.  I wanted one that was more Morse Code friendly.  That means a couple of things to me.  One is Morse Code weight. That is a measure of how long the morse code elements take to send.  The site http://www.radioqth.net/cwweight will allow you to enter multiple call-signs to compare weight.

Call Sign	Weight
AA4OO	58
N4PBQ	64

The other factor was how complicated the actual Morse code letters are to send and copy, i.e. the dit-to-dah transitions.  I'm not aware of a calculator for this but my former call N4PBQ had a lot of dit-to-dah transitions in the PBQ suffix.  When other stations would send my call back to me they would really stumble over the PBQ so I wanted something simpler.  I've worked a number of stations with 'E' in their suffix and I find that hard to hear so I didn't want something like N4EE because people would miss the DIT or hear an I.

For the prefix, the letter 'A' is simple to send (just squeeze and release for paddles) and the letter 'O' while being long to send is likely one of the most distinctive and easy to recognize letters in the Morse alphabet.

For phone contacts it's also an easy one to say: Alpha Alpha Four Oscar Oscar

Thus AA4OO was chosen

Say it out loud in Morse and it sounds cool.

Play / Pause

Learn CW Online - LCWO.net -
Text to Morse Converter

Extra Vanity Call Sign Information

The website http://www.ae7q.com/query/ has excellent information on vanity callsigns and their availability.

I would have liked to have a 1x2 or 2x1 (i.e. A4OO or AA4O) call but as you can see using the website http://www.ae7q.com/query/ the 1x2 and 2x1 extra calls are completely taken for most regions and the competition is fierce when one comes available.

Changing call signs requires some updates

It takes about 19 days after applying for an available vanity call sign for the FCC to grant it based on some rather arcane rules that are described at this link. After the FCC assigns your new call don't forget to update your call on your LOTW account as well as any clubs you belong to.  The QRZ site will automatically update your call after a few days from its FCC database feed.

That's all for now

So lower your power and raise your expectations

72/73

Richard AA4OO (formerly N4PBQ)

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)

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