Steve, This is really helpful. One point of clarification: now that the 12V is not traversing the coax, what power source are you using? Solar panel + battery, or other? 73, David G3WGN M6O
-----Original Message----- From: VE6WZ Steve <ve...@shaw.ca> Sent: Saturday, April 1, 2023 12:35 AM To: Frank W3LPL <donov...@starpower.net> Cc: topband <topband@contesting.com> Subject: Re: Topband: 2-element receiving arrays I received a few private emails asking similar questions about my power redesign of my amps. I need to clarify this. Yes, I have redesigned a version of a HI-Z amp that does not use 12v on the coax. Each require a dedicated 12v supply line. I right now have about 15 of these amps deployed in the field for my new BOG broadside phased array system. I have not yet swapped out the amplifiers on my 9C for a redesigned model because so far they have remained noise stable. However, all the amps in my 9C have had the PCB judiciously cleaned and carefully coated. Another question was have I actually seen this noise problem from micro-arcing? The answer is yes. Absolutely. In some cases it became very bad. In all cases this was on poorly cleaned and un-coated PCBs that developed moisture. On at least 5 of the amps I could actually see what looked like galvanic corrosion developing at the F-connectors on the PCB. A white dusty powder had developed across the connector. This was not because of serious water intrusion, but just moisture and humidity developing in the boxes. If some day I switch out the amps I have now, I will not use a bias-T voltage supply. As for modifying the combiner not much is required except to snip the RFC at each f connector and supply 12v through an RFC to the supply line going to each amp. Steve, Ve6wz From Babcocks iPhone > On Mar 30, 2023, at 6:31 PM, VE6WZ Steve <ve...@shaw.ca> wrote: > > I strongly second Franks comment about weather proofing. > > Equally important on any outside electronics is to very carefully clean ALL > the residual flux off the PC boards, and especially on the F-connector solder > pads. > ALSO, apply some acrylic conformal coating on all outdoor PCBs. > > With 12v on the coax line with a bias-T setup, even small amounts of dirt > stuck to old flux and then combined with moisture can cause serious noise > issues with micro conduction between the centre conductor and ground pads. > > I have since redesigned all my rx amplifiers to use a separate 12v dedicated > supply voltage to keep the DC off the coax. > > 73, Steve Ve6wz > > Sent from my iPad > > > On Mar 30, 2023, at 2:18 PM, Frank W3LPL <donov...@starpower.net> wrote: > > > > Tiler, > > > > Congratulations on your new five circle YCCC array! > > > > Be sure you very effectively waterproof all of your coaxial cable > > connectors that carry DC power. Even the slightest amount of > > moisture in the connectors will cause micro-arcing of the DC voltage, > > raising your noise floor by many dB. > > > > 73 > > Frank > > W3LPL > > > > > > From: "K3MM" <k...@verizon.net> > > To: "Frank W3LPL" <donov...@starpower.net>, "topband" > > <Topband@contesting.com>, "PVRC" <p...@mailman.qth.net> > > Cc: "Pete N4ZR N4ZR" <pete.n...@gmail.com> > > Sent: Thursday, March 30, 2023 8:08:42 PM > > Subject: Re: Topband: 2-element receiving arrays > > > > I just completed building a YCCC nine Circle array using V E6WZ PC boards > > with the latest mods, including on board chokes. I actually have it > > deployed currently as a five circle As I’ll be taking it down soon for > > mowing season, but it works quite well. The patterns on all three bands, > > 160 through 40 are as advertised. Very good patterns but not the best > > sensitivity . I built mine as about 23 foot verticals. I’d say compares > > favorably to my 500 foot beverage, antennna although it requires a lot of > > pre-amplification. Due to the active electronics it can be overloaded by > > close transmit antennnas so perhaps not as useful for a multiband operation > > in a small area. > > I’m providing power over the coax cable and using green heron everywhere, > > wireless remote control, which works quite well and is controlled by the PC > > software using a mouse or hotkeys. > > > > It was a fun project. It turned out quite well, but not in expensive. I > > scrounged about half the aluminum tubing and angle I’m using for the bases > > and probably spent $1500 or so. including the remote control hardware. next > > fall, I’ll deploy the full nine circle array, but the five circle is > > probably almost as useful and avoids some complexity and cost. i’ll also > > probably relocate it to get more separation from some of the transmit > > antennnas. > > > > Ty K3MM > > > > [ > > https://apps.apple.com/us/app/aol-news-email-weather-video/id6461006 > > 61 | Sent from the all new AOL app for iOS ] > > > > > > > > On Thursday, March 30, 2023, 1:38 PM, Frank W3LPL <donov...@starpower.net> > > wrote: > > > > > > Hi Pete, > > > > For a monoband receiving array, you might consider using low > > impedance resonant verticals rather than high impedance verticals. > > > > The primary advantages of high impedance verticals are > > - very short verticals (but taller verticals produce stronger > > signals) > > - multi-band operation > > - no radials > > > > The primary disadvantages are > > - reliability issues with outdoor electronics > > - lightning susceptibility of outdoor electronics > > - higher cost > > - much lower signal levels > > - extreme care required to suppress common mode signals (buried > > feedlines are highly recommended) > > - negative effects of nearby trees and buildings. > > > > The primary advantages of low impedance verticals are > > - much stronger signal levels > > - much less criticality of common mode signal suppression, > > - much lower cost > > - much higher reliability > > - immunity to lightning damage > > - much less affected by nearby trees and buildings > > > > The primary disadvantages are > > - taller verticals (typically about 24 feet) > > - radials (they can be very short if many radials are used) > > - mono band operation (switchable matching networks can be used for > > multi-band operation). > > > > I highly recommend the DX Engineering Receiving Antenna Phasing System. > > Its expensive but well worth the investment especially for a small array. > > > > [ https://www.dxengineering.com/parts/dxe-ncc-2 | > > https://www.dxengineering.com/parts/dxe-ncc-2 ] > > > > If you have 120 feet for a three element array, the YCCC array is a > > great choice It can use high impedance or low impedance verticals > > Unfortunately its no longer available from DX Engineering The nine > > element YCCC array uses only three active elements at any time, so > > its really a three element array switchable in many directions. > > > > [ > > https://static.dxengineering.com/global/images/instructions/dxe-yccc > > -switch.pdf?_gl=1*1cv0fc9*_ga*MjEyMDA1Nzc3MS4xNjUyMzAyMjc0*_ga_NZB59 > > 0FMHY*MTY4MDE5NTk1OC40My4xLjE2ODAxOTYwNTYuNTAuMC4w | > > https://static.dxengineering.com/global/images/instructions/dxe-yccc > > -switch.pdf?_gl=1*1cv0fc9*_ga*MjEyMDA1Nzc3MS4xNjUyMzAyMjc0*_ga_NZB59 > > 0FMHY*MTY4MDE5NTk1OC40My4xLjE2ODAxOTYwNTYuNTAuMC4w ] > > > > [ https://www.youtube.com/watch?v=dl-crM5Kb6A | > > https://www.youtube.com/watch?v=dl-crM5Kb6A ] > > > > [ https://www.youtube.com/watch?v=lVW1CmrzP7c | > > https://www.youtube.com/watch?v=lVW1CmrzP7c ] > > > > A two element array occupies only 60 feet or even a little less. > > > > 73 > > Frank > > W3LPL > > > > > > ----- Original Message ----- > > From: "Pete N4ZR N4ZR" < [ mailto:pete.n...@gmail.com | > > pete.n...@gmail.com ] > > > To: "topband" < [ mailto:Topband@contesting.com | > > Topband@contesting.com ] > > > Sent: Thursday, March 30, 2023 12:54:30 PM > > Subject: Topband: 2-element receiving arrays > > > > Thinking ahead to next winter on 160, I'm interested in replacing my > > K9AY Loop with a 2-vertical phased array. I'd like to homebrew the > > antennas and just buy or build the remote control unit for the shack. > > I'm looking for sources of components (antenna-located preamps and > > an in-shack controller), and would prefer not to completely homebrew > > them, but the prices at the usual suspects are awfully high. Any ideas? > > > > I have pretty reasonably-priced access to 25 and 31-foot fiberglass > > poles (used for wind-socks by model airplane enthusiasts). I'm > > thinking that one relatively low-cost approach might be to attach, > > say, #14 wire to the poles, with preamps at the base, but wonder if > > there is a downside to using such small-diameter antenna elements > > rather than 1 or > > 1.5 inch tubing? Alternatively, are clones of the DX Engineering 8' > > short verticals with preamps a good alternative? > > > > -- > > 73, Pete N4ZR > > _________________ > > Searchable Archives: [ http://www.contesting.com/_topband | > > http://www.contesting.com/_topband ] - Topband Reflector > > > > BQ_BEGIN > > > > > > > > BQ_END > > > > > > _________________ > > Searchable Archives: http://www.contesting.com/_topband - Topband > > Reflector > _________________ > Searchable Archives: http://www.contesting.com/_topband - Topband > Reflector _________________ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector