If the 40 dipole is expected to work on 15 and it is full-sized, the 
third harmonic resonance frequency will be somewhat higher than 15 meters, 
perhaps 22 MHz or more.  This is because the 468/F formula for a half-wave 
dipole includes a correction for what some call the "end effect".  Also, the 
15-meter mode will have several lobes instead of the simple figure-8 pattern 
of a dipole, so some directions may fall into nulls.

During the CQWW contest, which I operated for about 13 hours, working 40 
through 10, I worked 320 stations in 82 countries on 10, but only 55 
countries on 15.  It was a matter of allocation of time during the various 
openings.  Ten meter phone is so much fun because a contest can spread out 
over more than 700 KHz (28.3 to above 29.0), while 20 is only 200 KHz wide 
and 15 only 250.  This gives a lot more stations the option of calling CQ 
and you have less frequencies that are 2 or 3 layers deep in QSOs.  Also, 
you don't hear as many of the stations in your own country on whatever band 
is the highest in frequency at a given time.  This QRM factor is not such a 
big deal in CW contests.



Lloyd Rasmussen, Kensington, MD
http://lras.home.sprynet.com
-----Original Message----- 
From: Tom Behler
Sent: Sunday, October 27, 2013 10:11 PM
To: [log in to unmask]
Subject: Re: 10 and 15 meters continued

Steve:

I guess that's what confuses me a bit with the 15-meter portion of my Alpha
Delta DXCC.

The thing works so well on 40, that you would think it should perform well
on 15 meters too, especially if it uses the 40 meter part of the antenna to
tune on 15.

A good friend of mine has an MFJ antenna analyzer, so I may ask him to come
over here and see where the antenna actually resonates on 15 meters.

That hopefully should tell me something.

Tom Behler: KB8TYJ

----- Original Message ----- 
From: "Steve Forst" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Sunday, October 27, 2013 10:04 PM
Subject: Re: 10 and 15 meters continued


> Tom,
>
> Sounds like you had fun.  Svalbard is  between the Top of Norway and the
> North Pole.   It belongs to Norway, but is far enough away so it counts
> as a separate DXCC country.   I don't see them very often, but did work
> them  a few weeks ago in the WAE SSB contest.
>
> I did a little bit of S and P this weekend, mostly on Saturday.   A
> number of JA's on 10 and 15, Guam and Ascension island on 15, and  2
> from Kazakhstan and also the persian Gulf  on 10 meters in the morning.
>   Didn't hear anything on 160, but the higher bands were so good, it
> didn't matter.
>
> As for your antenna on 15 meters:  If I'm not mistaken, it's full size
> on 40, loaded for 75/80, and has 2 parallel dipoles for 10 and 20
> meters.   I think the idea is that since 40 and 15 meter bands are
> harmonically related,  there is no "real" 15 meter section, and so you
> tune   the 40 meter part on 15.
>
> If the performance is that poor, maybe you can rig up a  single band 15
> meter dipole somewhere.
>
> 73, Steve  KW3A
>
>
> On 10/27/2013 9:29 PM, Tom Behler wrote:
>> Hi, again, all.
>>
>> Most of the contacts I mentioned were on 10 and 20 meters.
>>
>> For some reason, which I'm going to have to investigate, my DXCC tunes,
>> but
>> doesn't seem to get out quite as well as I think it should on 15 meters.
>>
>> Tom Behler: KB8TYJ
>>
>>
>>
>