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Antennas, Feedlines, Towers & Rotors

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Trees and antennas

Posted: 05 Mar 2017 01:19 AM PST
http://forums.qrz.com/index.php?thre...tennas.557820/

I am planning my HF antenna. I would like to camoflage it a bit by putting
it between two trees. One being an Arbor vitae. Is this a bad plan
attenuation wise? Being in an HOA is restrictive. I was going to use a DX
engineering rotating mount to bring it down when not in use.

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Cascading stub matching networks

Posted: 04 Mar 2017 05:57 PM PST
http://forums.qrz.com/index.php?thre...tworks.557823/

Cascading stub matching networks

Been doing some research and actual work on stub matching - using serial
and parallel (stub) transmission lines.

My main resource is Walter Maxwells "Reflections".

I have a decent understanding how SINGLE matching network works, but ...



I have designed a phasing harness using two matching networks in parallel
connected to another matching network - in serial with this parallel
combination .



I am not sure it can work since the load of the first network is...



Cascading stub matching networks

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Best type of co-ax to bury sub-soil?

Posted: 04 Mar 2017 05:20 PM PST
http://forums.qrz.com/index.php?thre...b-soil.556929/

I want to erect two beverage antennas, for reception on LF and one LF
antenna for TX. What are the best types of co-ax to bury sub-soil and not
deteriorate too much? Being LF might help keeps cost down, but the TX one
would have to be co-ax able to handle a kilowatt or more. Runs would be 50
meters or so for the RX one and 100 meters or so for TX. Thanks.

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Rotor with a stuck mounting plate bolt.

Posted: 04 Mar 2017 05:17 PM PST
http://forums.qrz.com/index.php?thre...e-bolt.557154/

Rotor is in good condition all except one rusted bolt (that broke off) that
mounts the rotor to the rotor plate.



The bottom cant come off b/c the wires that connect to the terminals are
soldiered on... Plus that terminal is pretty rusted as well.



Can/should I soak the bottom in vinegar?



I plan on replacing the terminals with Rotor-Parts QC weather proof
connector.



Soak the bottom in penetrating oil.



I guess what Im asking is the best approach to this broke off rusted bolt.



I can...



Rotor with a stuck mounting plate bolt.

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Need help on running new cable on a MA40 tower

Posted: 04 Mar 2017 04:53 PM PST
http://forums.qrz.com/index.php?thre...-tower.555749/

I have a used MA 40 crank up tower.It had been on the ground for some time
and I need to replace the cable. I have tried US towers but to no avail.
run around. I did get size of cable for this unit but. I need directions on
how to remove the top of the tower and get cable re threaded. Is there a
manual ?



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Glen Martin Hazer Question

Posted: 04 Mar 2017 03:13 PM PST
http://forums.qrz.com/index.php?thre...estion.557800/

If I understand how these work, should the rotator die in the wrong
position, lowering the hazer to work on the rotator would be problematic,
no?

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Small Magnetic Loop Antenna - Coupling to Nearby Objects

Posted: 04 Mar 2017 10:34 AM PST
http://forums.qrz.com/index.php?thre...bjects.557749/

Can anyone please advise how much loss a small magnetic loop antenna - such
as an Alex Loop or Alpha Loop - would incur when placed next to a large
metallic object such as an automobile?



Im imagining a scenario - say a cold, winter day; or a hot, summer day -
where one might wish to operate from the comfort of their vehicle, with the
antenna (and its capacitor tuning knob) at arms length outside the window.



Is this feasible in a practical sense, or are the RF losses and pattern
disruption...



Small Magnetic Loop Antenna - Coupling to Nearby Objects

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Building a 7-foot diameter QRO STL for 40M in my HOA backyard

Posted: 04 Mar 2017 08:40 AM PST
http://forums.qrz.com/index.php?thre...ckyard.552730/

Last year I started to build a two-turn (N-turn) small transmitting loop
for 40M operation out of 32 feet of 1" Heliax that I scored at our annual
hamfest. Suspended by a large PVC frame, the beast was about 5.25 feet in
diameter yet still manageable as far as moving it around in and out of our
backyard HOA common area.



Yet shortly after acquiring a hefty 20-300pf Comet vacuum variable cap to
tune it I found out that I would actually need a bit less capacitance to
tune it to the Extra...



Building a 7-foot diameter QRO STL for 40M in my HOA backyard