Tom,
Final thought. Earlier I said the 15 meter resonance was a third
harmonic, I should have said "odd multiple of the 40 meter frequency",
which is why you multiply by 3.
73, Steve KW3A
On 10/27/2013 10:44 PM, Steve Forst wrote:
> It would be great to get someone over with an analyzer. You can also
> do some SWR checks across both 40 and 15 meters to see what is up.
> Tuners out of line.
>
> I think if you are resonant high up in the 40 meter band, you will be
> out of band on 15. There is a third harmonic resonance, which is why 40
> and 15 line up. If your 40 meter dipole is resonant at 7.100, then
> times 3 will put you at 21.300. Right in the middle of the phone
> portion of 15. On the other hand, if 40 meters is resonant at 7.250,
> then times 3 puts you at 21.750, (out of band).
>
> If this is the problem, you may have to tinker/compromise on 40 meter
> resonance to get 15 meters in band.
>
> This is a popular antenna. I would wonder what Alpha Delta says about
> 15 meter performance. I would probably do SWR plots and get the
> analyzer info before contacting them.
>
> 73 Steve KW3A
>
> On 10/27/2013 10:11 PM, Tom Behler wrote:
>> 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
>>>>
>>>>
>>>>
>>>
>>
>>
>>
>
>
>
|