[HamWAN PSDR] KU7M and his dBm

Thu May 22 13:28:28 PDT 2014

That's super weird.  You might wanna try moving the mount up/down the 
mast while keeping the dish level.  And yes, microwaves can be 
mysterious until you get experience with them.  That's one big advantage 
of doing a project like this, it gives hams motivation to learn how to 
deal with 6GHz and such.

--Bart

On 5/22/2014 1:03 PM, Kenny Richards wrote:
> Bart,
>
> >Would you like some tower climbing / install help?  That's some crazy uptilt on the antenna 
> picture you showed!
>
> Thank you for the offer, but I think it can wait until I'm healed. 
> This was 'minor' knee surgery and I should be back to working out in 
> six weeks, so I'm sure climbing the tower will be doable by then. We 
> are at the very beginning of tower climbing season....
>
> The crazy uptilt required was the source of most of my headaches. From 
> that exact location, I will hear nothing with the antenna at the 
> normal 'level' mount point. You need to tilt it up about five degrees 
> or more before CP will register.  It never occurred to me that it 
> would have that big of impact.  Microwaves are weird....
>
> Thanks
> Kenny
>
>
>
> On Wed, May 21, 2014 at 11:54 PM, Bart Kus <me at bartk.us 
> <mailto:me at bartk.us>> wrote:
>
>     Dean,
>
>     I wouldn't limit your potential upside to 3dB with ... "spatial
>     modulation".  :)  The vast majority of your path loss is NOT due
>     to distance.  If you did achieve clear (or better) LoS, you could
>     be looking at 30dB deltas.  Remember we've had Baldi-Tacoma (a far
>     longer distance than yours) run at -57dBm during a signal survey. 
>     K7JMM, across the Puget Sound (about 3x your distance) is running
>     at -58dBm right now.
>
>     Kenny,
>
>     Would you like some tower climbing / install help? That's some
>     crazy uptilt on the antenna picture you showed!
>
>     --Bart
>
>
>
>     On 5/21/2014 9:27 PM, Kenny Richards wrote:
>>     Dean,
>>
>>     I'm slightly less mad at you, but still a little peeved. :-)
>>
>>     The shot to Capital Park from my house goes through quite a few
>>     tree's in my immediate area. (All within a couple blocks from me)
>>      When I originally installed the tower about 10 years ago, I was
>>     able to see downtown from the top of it. Now I can't, due to the
>>     trees of the neighbor directly behind me and his neighbor.
>>
>>     That said, I don't actually have the HamWAN antenna mounted on
>>     the tower yet. I had to postpone that installation until my knee
>>     heals up. (Had the meniscus repaired in my left knee last week)
>>      Right now the antenna is mounted to a small mast at the apex of
>>     the roof. (It is sharing the mast with a VHF/UHF vertical)
>>
>>     I thought that I'd posted links to these pictures before, but I
>>     guess not.
>>
>>     Picture of current installation:
>>     http://www.ku7m.net/drop/KU7M_HamWAN.JPG
>>
>>     Picture of what I'm shooting through to get to Capital Park:
>>     http://www.ku7m.net/drop/KU7M_CPView.JPG
>>
>>     And just because it makes me laugh, the installation from the
>>     first night it started working:
>>     http://www.ku7m.net/drop/DeckAntennaMount.jpg
>>
>>     The difference in signal strength from the antenna being on the
>>     deck railing to its current location is ~5 dB. The height
>>     difference between the to location is about eight to ten feet.
>>     When moving the antenna to the roof the first time, I had
>>     originally installed it on a mast located at the far east side of
>>     the roof. In this spot I could not hear CP at all. By moving the
>>     antenna to the mast located in the center of the house (which is
>>     about 20-25 feet west), the signal appeared and has so far been
>>     the best location.  I ordered another mast mounting kit for the
>>     eve located at the far west side of the house. When I'm feeling
>>     better I'll install it and see if the signal improves again when
>>     moving west.
>>
>>     I don't have many data points on the impact of wind on the signal
>>     strength. I did check it on Sunday when a system blew through
>>     which was causing the trees to noticeable move. But I wasn't
>>     seeing much change in the signal strength. (maybe 1 db?)
>>
>>     Thanks
>>     Kenny
>>
>>
>>
>>     On Wed, May 21, 2014 at 7:44 PM, Dean Gibson AE7Q
>>     <hamwan at ae7q.com <mailto:hamwan at ae7q.com>> wrote:
>>
>>         First of all, Kenny:  welcome!  Now that you have a HamWAN
>>         connection, I hope you are no longer mad at me.  Where is
>>         your antenna (inside/outside, height above ground, etc)?
>>
>>         On a related but more serious side, do you have a direct
>>         line-of-sight path to Capitol Hill, or do you go through
>>         trees? The reason I ask is, my path goes through some trees. 
>>         When it is windy, that causes my RX signal level (dBm value)
>>         to vary about 5 dB (mostly down).  I have wondered whether
>>         mounting my antenna higher would help my overall value (of
>>         course it would help when it is windy).
>>
>>         My average RX signal level is 80 dBm (no winds), and yours
>>         appears to be 83 dBm. However, you are twice as far from your
>>         cell site as I am from mine, and since power falls off as the
>>         square of the distance, I'd expect (in similar configurations
>>         and siting) that you would experience a 6 dB difference. 
>>         Since the difference is only 3 dB, that suggests that (all
>>         things being equal, which they never are) I might gain *at
>>         most* 3 dB by moving the antenna.
>>
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>>
>>
>>
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