[50mhz] Re: 50mhz Digest, Vol 42, Issue 15

Mon Aug 20 19:55:35 EDT 2007

Hi,

This is not directly related to 50 MHz. I have questions about 70 cm and 
duplexors for 2 m/ 70 cm. I will be happy to discuss off forum if this is 
not the appropriate place to discuss it. My direct email is 
dan-schaaf at att.net

Otherwise, I will be happy to discuss it here.

Best Regards
Dan Schaaf
K3ZXL   www.k3zxl.com   "In the Beginning, there was Spark Gap"

----- Original Message ----- 
From: <50mhz-request at mailman.qth.net>
To: <50mhz at mailman.qth.net>
Sent: Tuesday, July 31, 2007 4:04 AM
Subject: 50mhz Digest, Vol 42, Issue 15

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> Today's Topics:
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>   1. Re: Good gain verticals? (Bill W5WVO)
>   2. Re: Good gain verticals? (mweisbergs at juno.com)
>   3. Gain Vertical Comments (J. Coote)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Mon, 30 Jul 2007 08:35:33 -0600
> From: "Bill W5WVO" <w5wvo at cybermesa.net>
> Subject: Re: [50mhz] Good gain verticals?
> To: <cboone at earthlink.net>, <kd4wov at earthlink.net>
> Cc: 50mhz at mailman.qth.net
> Message-ID: <08c001c7d2b6$e73c5480$0300a8c0 at BILLSLAPTOP>
> Content-Type: text/plain; format=flowed; charset="utf-8";
> reply-type=original
>
> Hi Chris,
>
> You wrote:
>
>> When the band is open, it doesnt really matter as to polarization.
>
> I've always believed this, because the polarization would obviously get 
> skewed
> in the active ionospheric layer. BUT... I've never seen any results from a
> side-by-side test using a horizontal and vertical antenna of the same gain
> (dBi) at the same elevation above ground during an E opening to see if 
> this is
> really true. Has anybody here ever actually done this, or something
> approximating it?
>
> The reason for my skepticism is that sporadic-E couds are very highly 
> charged,
> very planar (i.e., flat), and very thin -- all compared to the F layer, 
> which
> is structured very differently and refracts signals gradually back to 
> earth.
> E-clouds tend to act more like reflectors (mirrors) than refractors. The
> flatter and more highly charged the surface of the E cloud is, the less
> polarity distortion should take place. Theoretically.  :-)
>
> Which would imply that a horizontally polarized antenna of the same gain 
> and
> same elevation as a vertical might work better during strong sporadic-E
> openings (assuming, as is the case, that most stations are also using
> horizontally polarized antennas for DX work).
>
> Comments?
>
> Bill / W5WVO
>
>
>
>
> ------------------------------
>
> Message: 2
> Date: Mon, 30 Jul 2007 16:49:40 -0400
> From: mweisbergs at juno.com
> Subject: Re: [50mhz] Good gain verticals?
> To: 50mhz at mailman.qth.net
> Message-ID: <20070730.164941.-280669.1.mweisbergs at juno.com>
> Content-Type: text/plain
>
>
>
> On Mon, 30 Jul 2007 08:35:33 -0600 "Bill W5WVO" <w5wvo at cybermesa.net>
> writes:
>
>> in the active ionospheric layer. BUT... I've never seen any results
>> from a  side-by-side test using a horizontal and vertical antenna of
> the
>> same gain  (dBi) at the same elevation above ground during an E opening
> to see
>> if this is  really true. Has anybody here ever actually done this, or
> something
>> approximating it?
>
> There was a study done in the 50's, hosted by Oliver P Ferrel, an editor
> of CQ Mag. I'll see if I can find it in "my archives"
>
>
>> The reason for my skepticism is that sporadic-E couds are very  highly
> charged,
>> very planar (i.e., flat), and very thin -- all compared to the F
> layer, which
>> is structured very differently and refracts signals gradually back  to
> earth.
>> E-clouds tend to act more like reflectors (mirrors) than refractors.
> The
>> flatter and more highly charged the surface of the E cloud is, the
> less  polarity distortion should take place. Theoretically.  :-)
>
> I don't subscribe to this... thick or thin, refracted or reflected, the
> "bounce" results in a randomized polarity, whether the bounce takes place
> terrestrially or in the ionosphere. A more highly charged cloud (greater
> ion density) results primarily in stronger signals and a higher MUF.
> That's why, when the clouds are really charged, 2m opens up.
>
>
>> Which would imply that a horizontally polarized antenna of the same
> gain and  same elevation as a vertical might work better during strong
> sporadic-E  openings (assuming, as is the case, that most stations are
> also  using
> horizontally polarized antennas for DX work).
>
> A more viable explanation regarding the apparent superiority of
> horizontal over vertical during E-skip is in the nature of the skip.
> Assuming the textbook skip distance of 1200-1400 miles for a single hop,
> the E signal approaches the antenna at a far steeper angle than it does
> during F skip. When that skip shortens up to several hundred miles, the
> angle is steeper yet and interesting things happen. Indeed, I have often
> experienced -- while trying to peak a signal by turning the beam -- the
> situation of very little change in the signal, certainly not the usual
> 20db F/B ratio. The reason is that more of the signal is coming down on
> the driven-element than is coming across the directors. In other words,
> I've got a rotating horizontal dipole. That same signal, approaching a
> vertical antenna, is mostly in its dead-zone, hence the pronounced
> difference in reception.
>
> Guys with az-el rotors might try elevating their antennas during a
> short-hop session and see what difference it makes.
>
> An interesting historical note... back in antiquity, before the Brits got
> 6M, we would work them 6M/10M crossband (full duplex!) and I, for one,
> was getting decent signal reports. Many if not most of the G's were using
> their TV antennas to feed their converters and those were all vertically
> polarized with moderate gain.
>
> Bud K2YOF
>
>
> ------------------------------
>
> Message: 3
> Date: Mon, 30 Jul 2007 19:10:06 -0700
> From: "J. Coote" <TSCM at jps.net>
> Subject: [50mhz] Gain Vertical Comments
> To: <50mhz at mailman.qth.net>
> Message-ID: <OCEJKAMADJMKIEKGMBMDMEDPDEAA.TSCM at jps.net>
> Content-Type: text/plain; charset="iso-8859-1"
>
> List-
> Thanks for all the responses to my questions regarding antennas for 6M
> 73
> Jay
> W6CJ
>
> ------------------------------
>
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> End of 50mhz Digest, Vol 42, Issue 15
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