What they mean by coupling problem is that the antenna may be too near other conducting objects.

Perhaps it's too close to another antenna.  Or you have some resonant guy wires.  Or its too close to a metal roof.  Etc.

This may or may not be your problem.  Maybe something is installed wrong or is broken on the antenna ?

Rich,
A huge part of HF Yagi design is driven by mechanical constraints.  If you are making something for field day that will only need to last a few days in benign weather and is located where it's failure will not endanger life or property, then you have one set of constraints.  If you want to build something that needs to withstand 100MPH wind gusts in a residential area with zoning laws and insurance related issues, then you have another set of constraints.

There is a program called YagiStress available on ArraySystems site. I think and some other excel spreadsheet element calculator that you might be able to find on the web which give guidance on element failure due to stress induced by wind forces.

I think that 1inch diameter tubing at the center of full size 20 meter yagi is undersized for all but temporary use in very benign environment.  But this depends very highly on the element taper schedule you intend to use.  If you are talking about some reduced size Yagi maybe you come up with different requirement.

I think that you are asking about how much gap to have in the center of the element where you want to isolate the driven element from the boom and either half as you intend to do some kind of direct or perhaps hairpin feed system.  This gap is driven mostly by mechanical considerations.  What you do here will have some impact on the element lengths.  An Inch or two is more than adequate from an electrical standpoint unless you want to run super QRO.

They seem to have a great signal on 80m here in VA starting about 30min before Sunset until perhaps an hour or two after sunset and then they have periods of extremely fast QSB 10s of sec peak and long fade making QSO difficult.  There seems to be no peak on their sunrise. Based on this I think you should be in the shack a bit before dark and stay there until your enthusiasm dies or you make a Q.

I think that in the last day or so they have made some improvements to their receiving antennas.  Before that they would be very loud at SS working JA and then switch to EU with very few NA and having hard time getting callsigns right.  I think there was an operator change on Monday night 80CW and they went to SSB.  I was thinking well this can't be good...  For a while they were listening on a QRG with local ragchew.  After a bit they changed their listening QRG and I made a couple of calls and it was done and dusted.  I was pretty amazed.  Easy SSB QSO when I had previously called for many many hours on CW with much better SNR and was just adding to global warming???  You never know...

On Tues evening at my local Sunset they were very copiable on 160CW for almost 2hrs.  For part of that time they were about 579.  My RX antenna is K9AY in a very noisy 1/4 acre suburb.  They were pretty loud for a station that far away in the middle of landmass.  They were working EU making a good rate.  I could hear most of the EU callers so I zerobeat the last caller and added few 10s Hz offset and made easy QSO.  But I think that was just luck...I think the spotlight was shining on my station for long time on Tuesday.  On Monday they were much weaker here but folks a bit farther north (NY,NJ,PA) and NW(OH,MI,IN,IL) seemed to be getting some roving spotlight effect.

Recommendation for low band ops.  Try to find them near your SS...Be patient...Promise to follow the DX code of conduct...Maybe the spotlight will land on you...

But if you tune on their frequency or muff up your split button, the DX Gods will likely be mad at you and bad things will happen...I think some of the more polite ops may have a DX Voodoo doll that they are stabbing when they hear this bad behavior and at a minimum it keeps them from adding to the problem :-)  Maybe they also have some DF loops and are keeping a list of people they won't help with antenna projects. ;-)

Yes, they do have very good signal on the bands.  I think that they are on Rotuma even though the cluster spots are showing them on Fiji. 

http://www.qrz.com/db/3D2RX

Heard them on 160m CW on Tues at Sunrise ~12Z with decent signal and gave them a pass as others were calling and I have Fiji in the log.  Think that was a boo-boo...still need Rotuma. I could not hear them Wed AM on 160m but they showed up a bit late.  I hope they spend more time on 160m.

However while I was tuning 10m for 5X8C (too early but QRL won't wait) I did see some spots for them on 80m CW on Wed pretty late in the morning and decided to give a listen.  Sure enough they were pretty solid copy with very small number of callers.  I gave a few calls and they were in the log.  It was just a few minutes shy of a whole hour after SunRise !!! I guess you never know what will happen.

No brainer...

The AL80B is a way better amp.  More reliable tube, easier to tune.

The US has no reciprocal operating agreement with Cuba so you would need to get a Cuban license.

http://www.arrl.org/international-operating

This is not a math problem...

I am not even sure the problem statement is defined clearly enough to give a single answer if there was one.

As I understand it:
Ham A ~30 ft vertical with 36 radials and 1500W.  Location = Key West but more than mile from ocean if possible...
Ham B Force12 Tribander at 100ft and 200W.  Location = within few hundred yards of A.

Outcomes:
Frequency of operation 14,21,28MHz.  Almost all of the time B will be louder at BS7.  Way louder and hear better as well.  How much louder may depend on the specific F12 antenna model and the actual band used.

Frequency of operation 18 or 24 MHz. A might be louder but probably would not hear as well.   Station A being louder requires the autotuner to be close to the vertical or some low loss transmission line system.  Might be a bit tricky at 1500W...

Frequency of operation below 14MHz.  I doubt this is the scenario, but if it is then most likely A is louder on 80,40 or 30 meters.  If B can load the tower as vertical on the lower bands and has a good ground system it might be close on 80m.  If the band was 160m, (unlikely) and B had tower fed as a vertical then B would be many dB louder.

But at the last BS7 activation most of the east coast QSOs were above 14 MHz.  Sunspots were lower then but 14MHz was a good choice.  Maybe if it was now, 15m might be stronger.  I'd still want the yagi at 100 ft...

Yes, I agree with almost all...

I think my viewpoint was just slightly different.  I think that Mark has only had directional gain antenna for short while...year or so....  So if that's true, I think some more time and some of the tough ones that are on the air from time to time will be worked.  

The polar paths are often tough,  but if you are in the right place at the right time, magic can happen.  These paths are especially productive around the equinoxes.  

You are right, if you can't hear them, you can't work them.  But there are various reasons for not hearing...If others in your region with similar setups can hear and you are on at the same time and can not, that bears investigation.  

I think that also he has had low power until recently.  So if that is also true, some of the ones that escaped before will be more likely to be bagged.

I also understand that some of the entities are one time shots for many ops.  But you never know... If its really important to you then do what it takes,  I am pretty dedicated and will get up at all hours to try to work a new one or new bandslot.  But I am less enthusiastic if I am not having fun...I like to be able to walk away if there are too many lids or bad operations.  I can go for a bike ride and come back on at 3AM if need be.  If my family needs me to do something, the DXing is lower priority...

I can't predict the future solar activity level and won't pretend I can...I have heard and worked a ton of DX on the high bands even during the sunspot minimums.  Sure its tougher, and the openings are less frequent and often are strange, skewed, and hard to forecast.  I'd not rule out 10m, 12m, 15m even during the lull.  But they are generally less productive.  Who knows when this peak will be past?  Maybe a year or two?  Maybe 5 years?  Maybe it's already over the hump and headed down??  It will be fun to see what happens.

And you are right about the low bands.  They are loads of fun and when the high bands are dead or even if they are not, I love to tune the low bands.  Both 160m and 6m are favorites of mine.  I have heard lots of other ops say similar things, but I know it's not everyone's cup of tea.

So I completely and emphatically disagree with this statement.  I have heard some DXers badmouthing both hex beams and spiderbeams due to weak signals from some DXPeditions in the last few years.  I'd be overjoyed for a rare one to use these antennas.  If they take good ops and have some power and time then the game is ready to play...

The hexbeam is a just small 2 element parasitic array and is quite good for what it is.  Yes, a monoband 2 element yagi might have +1~ dB more gain.  A 3 ele yagi would be even better.  In some cases that might make a difference.  But in your case getting a legal limit amp would make more sense if you are hearing the stations, but not breaking the pileups 1500W/800W =+2.7dB .  Spiderbeams are better than many DXpedition antennas and if they are constructed correctly and pointed the right way by operators who know how to work weak openings quickly and efficiently everything would work better. 

I would never ever trade a tribander for a decent directional gain antenna that also has WARC band coverage.  If you have a better than average antenna on the WARC bands you have a significant DXing weapon in your arsenal. 

Your antenna is quite capable of working HR.  Obviously a better antenna might make it easier, but lots of guys have used worse antennas and lower power to get HR.  An antenna upgrade that might be possible depending on your situation would be to have a higher tower.  65 or 70 feet will be much better on tough paths than 40ft even if it is just a hexbeam or other two element yagi it will work better and have stronger signals most of the time on really long paths if it is up higher.  If you want to have more degree of freedom to battle the ground gain nulls that might occur on some paths due to strange propagation, then having a motorized crank up where you can vary the antenna height might make some tough paths easier or help to cancel RX interference.  It might offset the aesthetics issue as well.  But it's pretty expensive for the payback.

The biggest issue is that you need patience for the stations to come on the air at all.  Then you need to put in the chair time to make the Q.  Not everyone can or wants to do this part.  Everyone has other obligations and balance in their lives.  But what is the big rush anyway?  I like to think of it as the journey rather than only the endgame.  If you miss one it will likely come around again.  It may take quite a while for some of the entities but take time to have fun as you proceed.

Learn about propagation and what paths are open at what times of the year and when... For example in my experience S2 is always louder in VA Long path than Short path.  FH should come to you in time.  As will XX9 and XW.  Talk to other active DXers in the same region and try to learn from their experiences.  PS not all OT DXers have good advice.  Some guard their secrets like favorite fishing holes.  Some don't have a clue and never have... just a loud mouth and good station.  Others were top notch DXers at one point but have failing memory or other issues.  So take everything you hear with a grain of salt.
W2IRT has a ton of good advice, I just differ on opinion regarding hex and spiderbeam performance...

So let me make a final disclaimer...I do NOT have HR... I need less than a handful more, and this was done in about 12 years with very small station with some breaks and excursions to other hobbies.  I have had a linear amp for less than half of that time.  It's only an AL80B but it works well enough for me for now.  At present I have a mix of antennas that are mounted in trees and I can change element lengths on them as I want by raising and lowering with pulley system and can point 2 ele monoband yagi (17m Al tubing or add  copper alligator clip to THHN wire element pigtails for 20m band selection) or 3 ele monoband (10m Al tubing or add  copper alligator clip to THHN wire pigtails for 12, 15m band selection) yagi with armstrong method via tether rope on the ground.   This beam is no higher than 30 ft.  So your hexbeam is most likely better than mine on most bands due to height. Maybe on 10/12 my 3ele is a tiny bit better.  Some of my wire antennas are higher... My low band antennas are just wire verticals and short RX antennas.  The trick on my suburban tiny lot is battling RX QRN and QRM from power lines and electronic rubbish.  So you can see that the advice I have given regarding higher antenna and more QRO could apply to me equally, but I have not done so yet... 

Yes JD1 can be tough for east coast NA,  but JD1BMH is an exceptional operator.

He is on at favorable times and bands for east coast NA stations and has good signals.

Most of the JD1 operations have been small one or two man JA ops that work tons of JA but not much east coast...

JD1BMH is trying hard to put NA in the log so give it a try it may be one of your best chances for Ogasawara.

He was loud on 17 CW in the evening a few days ago.  He has been putting in a decent signal on 80 CW just before NA sunrise and he hears very well.

Good luck in the pileups.

I find that if an antenna is deaf on RX and heals temporarily post TX, that there is most likely a high resistance connection somewhere in the antenna.  What happens when you transmit is that the RF current makes a lower resistance connection like an arc welder that may "fix" the antenna for a short while until the high resistance returns.  But this temporary arc weld may still make for a poor connection and it may get worse with time.  Look at your coax feeder connection or balun to coax or balun to radiator connections or a bad PL259 to coax joint etc.  Look for corrosion and clean all the connections.  If its a multiband check the connections of traps or stubs or loading wires.

I find that most ferrite baluns are relatively unfazed by dampness or slight water at power levels up to 600-700W.  If they are sitting in a pool of water it would  be a problem obviously.  I don't think the balun is your problem unless it has an intermittent high resistance electrical connection.

I seriously doubt you need a preamp on HF.

With very very few exceptions most operators have excessive noise at the antenna that a preamp will not help.

One well known case where preamp might be of value is if you have a lossy receive antenna like a flag or beverage.

Otherwise skip the desire to just make the Smeter read higher and simultaneously lower your receiver dynamic range.

Run this simple test.  Terminate your coax in dummy load and listen to the receiver noise floor.  Then switch to the antenna under test on a clear frequency.  If the noise is noticeably louder than on the dummy load then a preamp will not lower the noise floor

If you are saying that your 20m hexbeam works better at 23ft than 40ft for long distance QSOs then you are mistaken.

I see lots of posts talking about antenna "efficiency".  There are lots of efficient antennas that are not good antennas.  The engineering definition of efficiency is that the antenna radiates a strong electromagnetic field relative to the applied source.  That radiation may go in a direction you don't care about like into the clouds or down into the dirt.


Depending on what supports your hexbeam, you could use it as a vertical radiator against a ground system.

I am not sure why you don't like using a tuner, but if it is fear of introducing significant loss, then it probably is unfounded if you have a half decent tuner and reasonable load impedance at 10 MHz.  If it is because it is a nuisance to tune and you only use it on one band then it seems like you could leave it set and bypass it on the other bands where its not needed.  But if you have to change it multiple times for different bands, I agree it can be a bit tedious.  Maybe I am missing your point?

Do you get the Processing Aborted - Invalid Certificate message?

If so see the hints under this section on:
 arrl.org/lotw-help.

I agree that you can get it sorted out if you call them.  If you don't want to talk to them you can open a help ticket by going to:
 arrl.org/lotw-help-ticket

I'd recommend that you log in and select the tab Your Account and then select Your Activity.

Look to see when the last log you submitted is indicated as File Processed.

If you see that a log was processed and you have no increase in your QSO records then there is some other problem.

If you see that a log was processed and you have an increase in your QSO record count but no matches.  Then you might have a logging problem like your time is off due to the time change or maybe some other error on your part.  Could be wrong band or wrong mode or wrong date or ??  Or maybe you just talked to ops who don't use LoTW.