Topband: R.e. Lew McCoy article from CQ (Slopers)
Pete: Going only by memory, I did have a quarter wave sloper on my 120ft. tower. This was some time in the late 80's or 1990 or so. As I remember, it got out surprisingly well. I remember being able to hold a run frequency in (probably) the ARRL 160m contest. I do remember working a lot of US stations- and that was with only a 100W transmitter BTW. I remember not being able to find a resonance, in terms of SWR minimum, but OTOH the SWR was not prohibitively high so I just used it and didn't worry about that. I say go for it. A sloper on a 50ft. tower should be easy enough to try. 73, David K3KY _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: FYI Robot contacts"outlawed" by ARRL
In other words, NO CHANGE. Non-audible contacts still count for DXCC. In a word, disgusting. Also disappointing. I stopped participating in the DXCC awards a while back, anyway. This ugly reality assures there is ZERO chance I would ever participate in that program again. The Dickensian character Ebeneezer Scrooge sums it all up thusly: "Bah Humbug!" David K3KY (You wrote:) Found it Mike va3mw 35. Ms, Jairam moved, seconded by Mr. Williams: WHEREAS, there has been a growing concern over fully automated contacts being made and claimed for DXCC credit, THEREFORE, BE IT RESOLVED, on the recommendation of the Programs and Services Committee, the Board directs that DXCC rule 6 be amended to add 6a, as the following: 6a. Each contact claimed for DXCC credit must include contemporaneous direct initiation by the operator on both sides of the contact. Initiation of a contact may be locally or by remote. _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: Summer Update & a Surprise
For ARRL non-members, who will not be able to access the article "Rotten Damped Spark Stuff" behind the pay wall, a Google search (www.startpage.com) on that phrase produced exactly one relevant hit: http://w2pa.net/HRH/spark-to-cw/ It's actually a pretty good summary of the beginnings of the demise of spark. I learned a few new things there. It does help put it all in perspective. I continue to be *Massively* uninterested in digital modes on HF radio in the form they are currently taking. (Yawn) I can do essentially all that on the internet all day long. But perhaps there is some truth to the notion that digital is 'saving' ham radio. I really don't know... Yes, ham radio will change. I'm OK with that. No, really... Young whippersnappers! When did I change into an old fart anyway? Somehow I missed that... I have returned to building gear with vacuum tubes, catering to my lifelong CW addiction. I find satisfaction working at the bench and sending or answering CQ's to what at times may seem like an empty band- or occasionally tuning down to the low end to see what DX I might find. Life is good... SM6CVX Hans may have it right. From my perspective, it does indeed appear that the sky has already fallen with respect to CW and 6 meters- and apparently top band is well on the way. If ham HF operation contracts into just a few clusters (of digital,) it would be understandable if the 'authorities', sensing weakness and seemingly vast tracts of unused frequencies, moved to shrink the ham bands. It has happened before (220MHz). Or perhaps they just take the ham bands by stealth by approving noxious wide band digital unattended messaging systems, commercial traffic in disguise. It seems unlikely that ARRL will ever de-conflict CW/SSB etc. vs. computer assisted modes for DXCC awards, but that is what it would take to fix this mess IMO. Thank you, my old friend CW, for all the happy memories. You will go on a while longer, still having many friends and supporters- even some young ones... 73, David K3KY > Original Message > Subject: Re: Topband: Summer Update & a Surprise > From: donov...@starpower.net > Date: Thu, August 01, 2019 12:13 am > To: topband@contesting.com > > > Rotten Damped Spark Stuff > > > http://p1k.arrl.org/pubs_archive/2989 > > > > > > - Original Message - > > From: "W0MU Mike Fatchett" > To: topband@contesting.com > Sent: Wednesday, July 31, 2019 10:30:27 PM > Subject: Re: Topband: Summer Update & a Surprise > > Same thing was said about SSB. > > The sky is not falling. > > K1JT might have saved Ham Radio. Seems to be quite popular. 60 plus > percent of all LOTW confirms are FT-X nowSpeaks volumes. > > There is room for CW, SSB, FT-X on topband and all bands. > > Criticizing people playing radio seems unproductive. > > W0MU > > On 7/31/2019 3:16 PM, Hans Hjelmström wrote: > > UNFORTUNATELY K1JT and FT 8 killed amateur radio on 6 meters. > > It will kill it on 160 meters,and SOON it will kill all amateur radio > > activity on all bands. > > > > Soon authorities will reduce our bands,as we do not use these frequencies > > any more. > > > > SORRY its all gone from enjoy ,challenge and efforts to a computer fake > > game. > > > > CW will be unknown in 20 years,as most of elder Hams are SK ,and newcomers > > do not need it. > > > > SAD and unfortunately facts. > > > > Kind regards ( still refuse FT 8 ,and will never use it) > > > > SM6CVX Hans > >> 31 jul 2019 kl. 18:39 skrev daraym...@iowatelecom.net: > >> > >> Interesting observations Jeff. I will remain on 160 CW as I have in years > >> past. I enjoy the visceral satisfaction that comes with pulling out the > >> weak signals and having direct, unencumbered interaction with the station > >> to which I'm communicating. . .or trying. . .hi. CW is still great fun. > >> > >> 73. . . Dave, W0FLS > >> > >> -Original Message- From: k1zm--- via Topband > >> Sent: Wednesday, July 31, 2019 7:20 AM > >> To: topband@contesting.com > >> Subject: Topband: Summer Update & a Surprise > >> > >> Hi Gang > >> > >> > >> It is mid summer here and E season on 6M has been fun to play with while > >> 160m is pretty S L O W as it usually is. > >> On these pages there has been alot of chatter regarding FT8 - (which > >> basically took over 6M DX'ing starting in July 2917 - all DX is now on > >> 50.313 FT8 - which is why I had to adopt this mode in order to continu
Topband: Transmit High Pass Filters for BCB Interference
I bought a DLW Associates FL1718 filter and have been completely happy with that choice. I got mine direct from Doug Williams because I wanted a custom filter with one of the notches centered right on the broadcaster's frequency. Specs say >90dB attenuation at that notch frequency. I was willing to accept a slightly less steep rejection skirt in order to get that optimized notch. http://www.dlwc.com/ I just ran a daytime check with my filter in and out of the line. My local BCB flamethrower indicates 50dB over S9 on my FT-1000D. Inserting the filter drops the S-meter reading to S2. Assuming 5dB per S unit, this is -85dB indicated- and this is without any special measures such as a better (low inductance) station ground or any inline chokes. Such measures should improve the ultimate rejection a little more. The broadcaster drops power considerably at night, and is then only faintly audible in my receiver with no S-meter deflection at all. The right location for such a high pass filter is between your Rx/Tx and any power amplifier- unless the transceiver happens to have unusually high transmitter power exceeding 200W. If I had to make this buying decision again I would buy this model again without hesitation. It's an amazingly effective filter, good for up to 200W on transmit. I wish the local broadcaster had paid for my filter, too- HI! 73, David K3KY _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: RFI on TB
Rumor has it PG&E is facing possible bankruptcy due to being found responsible for the big fire(s) in CA. That being the case, I would expect they would have to re-prioritize greatly- problems such as yours are, to them, 'lost in their noise' (pun intended). 73, David K3KY (You wrote:) I want to know how you guys get the power company to respond so quickly. I’ve been calling Pacific Gas and Electric for 6 weeks now and nothing. I can’t even get a phone call. Ken K6MR _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: Modern Grand Solar Minimum from 2020 to 2055?
A grand solar minimum would be so disastrous for upper HF. Although I'd very much enjoy working Asians on 12 and 10 meters again, it now appears that may be less likely. OTOH it would be of some benefit to have a quiet sun if the Earth's magnetic field is indeed ready to flip! I first got licensed as a ham right between Cycles 19 and 20- so as a new General class op in 1964 I was first exposed to dead minimum solar activity. At that time, working into Oceania in the evenings on 20m was a pretty big deal and often a surprise to a young, inexperienced ham. It sure made me appreciate the higher bands when they reawakened. 73, David K3KY _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: Recommended Relays
Hi, All- Looking back at some of the better construction articles I've saved in recent years, this one stands out: "The StationPro Master Station Controller" by W8ZR in QST, August 2010, page 30-34. He likes to do things up nice, and it sure shows in the finished product. It looks professional. In particular, his idea for the switching relays is top notch IMO. He chose Tyco/Schrack RTB14012F PCB mount types. They are compact, high current carry, low inductance (and how!), and also cheap. I have seen them on Mouser's site, seem to always be in stock. Maybe 3 to 4 dollars each by now. Certainly a useful relay design up through 6 meters, it appears. He says: "...easily handles the amateur legal power limit" (1500W) "...has excellent RF properties..." "In more than 20,000 hours of 24 x 7 operation with the four StationPro's in the author's station, there has not been a single relay failure." If you look at the PC baord he designed, you may agree with me- it's pretty much a masterpiece. He kept lead lengths to a minimum in these units. Especially considering the low price, I think these relays are going to be very hard to beat! 73, David K3KY Derwood, MD _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: OT - US Hams, WWV closure
That's a great suggestion, Paul. Very constructive. Assuming such a transfer from the federal government could be implemented, funding would be needed. So if the worst happens and these stations do indeed end up on the chopping block it might be a lot less an uphill battle to get hams and other incumbent users involved in a long term, sustainable funding scheme. I would personally support such an arrangement, within my limited means. It might take a lot of supporters to pull it off, but somehow I doubt that number would come *anywhere* near 100,000 individuals. Despite aspersions to the contrary, I *do* 'get it', and would sorely miss all those NIST services here. I guess some in our group fancy themselves mind readers? (grin) 73, David K3KY > Original Message > Subject: Re: Topband: OT - US Hams, WWV closure > From: "Paul Christensen" > Date: Thu, August 23, 2018 12:02 pm > To: > > > >"The cost savings they are talking about amounts to very little. It would > >cost a helluva lot more to dismantle them completely. Besides TIME and > >freq standards, WWV provides for a myriad of other features." > > Seems like a great opportunity to spin-off WWV/WWVB to one of Colorado's > state universities; WWVH to a Hawaii university. Let a university run it as > a STEM project under the auspices of their dept. of physics or engineering. > Assign an advisor to help lead the students into worthwhile projects and > responsibilities. Here's an opportunity for academic professors to lead by > example, not just teach. It's not like it takes expensive, and largely > unmotivated federal workers with their long-term FERS/CSRS expenses to keep > the stations running. Moreover, it should be easier for a school to secure > private, external corporate funding and grants as needed, rather than through > a U.S. federal agency. In time, upgrade/expand the existing buildings for > other university STEM projects. Let the universities work with high schools > - and get high school students motivated to pursue STEM degrees. Give them > operating shifts, special construction projects, write code for remote > station monitoring, etc. > > My university had two student-run radio stations, run under the direction of > an academic advisor. Never in my life have I met a more motivated group of > people who worked for free. We couldn’t get enough if it. The experience we > received was priceless. > > Paul, W9AC > > > > _ > Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Topband: OT - US Hams, WWV closure
Oooh- here's the deal with that- Although I totally agree with the intent of the petition, and would otherwise add my name to it, I have several problems with this: Please note, I DO NOT intend to stir up any political discussion here! (1.) 100,000 valid entries is indeed a massively uphill battle for an amateur fraternity numbering only around 700,000 or so for the entire US. What with rampant apathy and deep divisions in the country, I believe this may not be an attainable goal. Too bad. I would very much miss WWV and WWVH. I think they may well get the axe anyway. Too many promises have been made to the un-needy/ undeserving... and the country is hemorrhaging money anyway. (2.) I have always felt *very* exposed in terms of privacy. Up to now I have studiously avoided all lemming-like enterprises such as Facebook, Google, Pay Pal, Twitter, et al... OK call me a Luddite. I prefer, ahem, 'slow adopter'. And I am sooo glad today I'm not being exploited very much by such firms. Also I do anonomized searches (Startpage, DuckDuckGo, etc.) I have always been reluctant to give up any personal information to anyone unless absolutely necessary, i.e. for Social Security etc. How much less likely am I to want to get on a White House list or any other similar thing considering *today's* chilling, poisoned environment? Sorry, guys, I'll sit this one out. (3.) Even in the unlikely event the 100,000 milestone is actually achieved, what guarantee is there it wouldn't just fall on deaf ears? I strongly suspect the Executive Branch agenda isn't much congruent with the actual needs and wants of the majority- and that seems to be the case most of the time regardless of which party is in ascendancy... 73, David K3KY _ Topband Reflector Archives - http://www.contesting.com/_topband
Topband: lightning grounds for elevated radial antennas
Hi, Grant-
Seems like everyone is preoccupied with K5P and the deterioration of
160m DXCC standards, etc. Hi!
Here's what I have picked up over the years. My comments address
lightning mitigation only, and not issues such as RF ground quality,
reduction (choking) of common mode currents on feedlines, etc.
1. Coax feedline laying on the ground or buried is better than coax
in aerial runs from antenna to station
2. Frequently the shield conductor of the coax is connected to a
ground rod and/or short radials at the antenna end *plus* at the
station end
3. A good quality coaxial arrestor such as a Polyphaser where the
feedline exits the station is vital
4. A massive ground panel ('bulkhead') where all conductor shields
entering the building are tied together- ideally *everything* is
tied together here, house electrical service, phone lines, CATV-
even the rotator cable (often 8 conductors) crosses gas tube
arrestors on this same bulkhead
5. Some sort of impedance in series with the coax shield at this
point of egress, two good examples being a large coil of hardline,
solenoidal wound (single layer), large diameter, or else a
'waveguide below cutoff' such as passing the coax through about
ten feet of EMT tubing- grounded to bulkhead at station end, not
terminated on the side towards the antenna where the coax exits.
Could probably be oriented vertically or horizontally or bent.
BTW even a big hank of coax is better than nothing here, but a
proper solenoidal wound inductor is said to be better.
FWIW any of the various common mode chokes can only help in this
lightning mitigation (many examples being made from large coax
wrapped around large ferrite toroids, multi turns)- but the two
methods outlined above are probably way better from a strictly
lightning mitigation point of view. Further, those cores might
even be toast after a really big direct hit on your antenna
system (relatively rare event). Induction currents from nearby
strikes are probably not an issue, however...
Summary:
***Encourage the lightning pulse to discharge from the
coax shield into the ground as soon and as often as possible;
***Provide as high as possible an impedance to lightning currents
in the coax shield right at the point of egress from your station
(for coils, inboard from a ground rod on the antenna side but prior to
the entry bulkhead);
***Bypass any remaining differential mode lightning energy
from center conductor to ground right at the bulkhead using a
good quality arrestor.
Final point: lightning can laugh at all your efforts and
sneak into your house anyway if you have overlooked anything.
All it takes is the oddball telephone cable or extension cord
you ran through a window and forgot about- or multiple service
entries for CATV, power, telephone, ham feedlines, etc...
Polyphaser has a great little book I got a lot out of from reading
and re-reading, called (from memory) "The Grounds for Lightning
and EMP Protection" (or something close to that, anyway). Turns
out the ideal protection scheme follows the single point egress/
massive ground bulkhead scheme *slavishly*. No exceptions allowed.
And a massive perimeter ground is put all around the foundation
of the building, with massive copper strap connections, cad-
weld connections, ground rods every ten feet or so, etc. Most
hams are not going to take it that far. I never did- but the
very well grounded copper bulkhead is well within reach for
many/most ham homeowners. See W8JI's excellent photo presentation
of how he did this on his website.
73, David K3KY
A lengthy thread re grounding on towertalk prompts me to have concerns
about protection of my T top (85' to top plus two 33' top wires) wire
160m vertical with eight 125' elevated radials. Since that covers more
than an acre (it's mostly among 100' tall conifers) it has a lot of
target area, radial routing close to trees, and high ground
capacitance. I did DC ground the vertical via a 3 core 240-31 choke,
about 5k ohms to a single ground rod but that was for static protection
of radio front ends. The antenna is fed via a 50:25 ohm TLT so the
radials have a DC connection to the choke.
What is best practice for lightning protection of elevated radial
verticals?
Grant KZ1W
_
Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Topband Re: Ground Screen Question
Hi, Bob- I'm really seeing two or more issues here. There has been some debate as to whether or not tying in a ground screen to elevated radials is a good thing or a bad thing. I'll leave that discussion to other topbanders who have a lot more experience in that area. My understanding is that even a ground screen NOT attached to the antenna ground return conductors (radials, counterpoise, etc.) may still be of benefit. Regarding the elevated radials, I'd suggest that you might want to weigh the possibility of using a K2AV FCP rather than the rather skimpy radial count of only four wires. I'm surprised there have been only a few replies in this thread. Regarding the reinforcement wires in your driveway, of course they could be connected to other ground screen conductors. It might help how well it all works; the only fly in the ointment is possible concerns about a direct lightning hit. If you get that unlikely big direct hit, there can be a huge current surge to ground, on the order of ~100,000A. Looking at how tower grounds are deployed (ideally) we see multiple large diameter conductors bonded to at least three ground rods near the tower legs (or often wide copper strap). Often the ground is extended out to more ground rods, sometimes splitting to two connected rods, etc. The idea is to spread the current out symmetrically away from the tower base. Connections are often done using 'cad weld' techniques, where a very hot exothermic reaction essentially melts the conductors to the rods. This is to handle the huge currents in a direct strike. If you do connect to your concrete reinforcement wires, I would guess that multiple interconnections might be good, if they do contribute to current spreading during a direct hit. For sure, if you ever do get that direct hit, there are going to be large currents in all nearby conductors, including buried ones. I'm having a hard time visualizing how you figure out where to drill to hit those embedded wires, then how do you get enough room to get in there and make a good connection to the wire? I'd guess it really ought to be some sort of compression connection. It needs to stay together if a huge current spike happens. It would also need to be weatherproofed, somewhat, to prevent rust and eventual failure to maintain an 'ohmic' connection (non-rectifying). I would think that just wrapping a few turns of wire would eventually result in a non-ohmic connection- especially if the wire types are dissimilar (Cu/Fe). I think I'd want to do that with some sort of clamps. Do you have enough room down inside a bore hole to do that? What would scare me the most would be if you made a single connection of the driveway wires into a heavy (proper) tower ground. During a lightning hit, a LOT more current might try to pass through that one joint, dissipating through and in the center of that big block of concrete. Odds vastly favor your never taking such a hit, but if you do... For lightning mitigation, having little or nothing to do with the overall quality of your RF ground, I suggest that keeping 'current spreading' in mind is always a good idea. 73, David K3KY Dave, I see your point. I wouldn't want to chance damaging the concrete. I am not thinking of attaching to the tower with it however, I am thinking of it as a ground screen and actually adding more welded wire mesh also at about a 15 foot radius around the base of the tower which would be connected to the slab mesh. The ground screen would not be attached to the tower and will help with near field losses from the shunt feed tower. What I am thinking of for radials is 4 elevated radials at 14 to 16 foot above ground. This height works well with my trees, etc on the property. Radials will not connected and completely independent of the ground screen. I don't have a huge lot so the radials will have to be bent at 90 degrees when they approach the property lines. Not ideal but I'm hoping with a little help from the ground screen I will have a decent signal. I did an exploratory hole in the concrete slab and the 6x6x no 8 wire grid is like new, no rust. I guess the concrete preserves it. I have two 8 foot wide by 70 foot long runs of the welded wire mesh imbedded in the parking slab. I will make sure each of the two runs is electrically tied together. So what I will end up with my proposed ground screen is wire mesh ground screen extending out from the base of the tower with a 15 foot radius and it will attach to the adjacent 15 foot by 70 slab ground screen. I figure why not use the 15 x 70 slab too if doable ? Sound OK ? Any other ideas suggestions ? I appreciate the input guys ! Bob K6UJ _ Topband Reflector Archives - http://www.contesting.com/_topband
Topband: RE; Ground screen Question
No confusion at all, Jim. I know the difference between the two. His reinforcing steel inside his driveway is probably way far out of the realm of Ufer grounds, due to it being small gage conductors. Aside from the great difficulty of boring into the concrete and adequately bonding to those wires, I wouldn't try this anyway out of concern that the current density during a major lightning hit might be sufficient to produce widespread cracking of the concrete. Now I'll have to go re-read and brush up on Ufer grounds, but as I remember, his driveway setup would be woefully inadequate for the possible current levels involved in the event of a direct lightning strike. Personally, I wouldn't go there. A concrete drive would be a little pricey to replace, especially considering the relatively small prospective gain in HF ground quality he might see by connecting his radial field to it. I'd much rather connect *over* that drive using strategically sawed grooves and lightly concreting in a few wires at the surface in a few places- this assuming he has somewhere to go on the far side of the drive with those wires anyway. I know a ham who thought his well pipe might make a dandy addition to his ground radial system. He connected it, and eventually had to replace a 600 dollar well pump after a strong lightning hit on his property. This driveway question reminds me of that. Properly designed Ufer grounds, fine- but I sure don't want to invite lightning hits to dissipate through anything concrete on my property. My two cents (two dollars, adjusted for inflation...) David K3KY There is considerable confusion here with respect to radial systems for antennas and an earth connection for lightning protection. They are VERY different, and both are important. Properly bonded conductors buried in concrete ARE acceptable as a ground for lightning protection -- it's called a Ufer ground, after Herbert Ufer who developed the concept, and it's now recognized in the National Electric Code. A Ufer ground works because 1) concrete is conductive and 2) there is a large surface area in contact with the earth. The downside is that the earth it makes contact with is near the surface. Like ALL earth electrodes, it must be bonded to all other grounds in your home -- power system, Telco, CATV, your shack, and all driven rods. I think Bob is on a pretty good track with his design. For more ideas, see http://k9yc.com/160MPacificon.pdf 73, Jim K9YC _ Topband Reflector Archives - http://www.contesting.com/_topband
Topband: Ground Screen Question
Hi, Bob- I wouldn't risk this, personally, for the small benefit that might be gained. Consider- if your tower ever takes a direct lightning hit, nearby ground currents can be very high indeed. There are some cases documented where concrete fractured or even exploded as a result of these violent internal currents. Even many decades old, it still has some internal moisture content. During the pulse, it flashes to steam. That energy has to go somewhere. The same thing happens when lightning shatters a tree- due to the high current density, the internal sap flashes to steam and the tree literally explodes. If I were looking at this problem, I'd be asking myself "how can I encourage the pulse of current to spread out alongside and parallel to the driveway?" Our neighbors took a direct hit to their roof a few decades back- some recently planted shrubs next to the underground transformer in their front yard literally exploded out of the ground and landed some 15+ feet away in the street out front. I would never underestimate the potential for mayhem when it comes to lightning. 73, David K3KY Topbanders, I searched the archives under "ground screen" and could not find info on my situation. I have a 15 foot by 70 foot, 6 inch thick concrete parking slab along side our house. My tower is about 15 feet away from the side of the slab. I am planning radials to extend out from the tower which I will be shunt feeding for 160M and remembered that the slab has welded wire mesh reinforcement at mid depth. The welded mesh is 6 in by 6 in and # 8 wire. Would the mesh be a good ground screen ? I will have to drill and connect to the mesh at various places but would be worth it if a good ground screen. Bob K6UJ _ Topband Reflector Archives - http://www.contesting.com/_topband
Topband: Low Power TX radio 1980
My best guess, based on what little information you have given here, is that the radio contains a *Seiler* Oscillator. I've not run across any reference to a "Sillner" oscillator prior to yours. The Seiler is a variation on the basic Colpitts type. Unless you can provide additional info on your radio, I doubt you have given enough for anyone to be able to help you. How about at least a link to a photo of your radio? 73, David K3KY >I have that QRP radio and need to get it working. If you have a schematic >I would be more than happy to Pay for the copying and mailing of that Radio. >I Believe it has a VFO that was called a Sillner VFO. I can not find any >Information on it. I would like to have it working for the late summer. _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: K6STI low noise receive loop
exercise to swap in the phasing harness and matching network later. It will likely get quieter (i.e. lower output). Try it and draw your own conclusions. BTW the authors, K6STI and W6KUT put strong emphasis in using the RIGHT open wire phasing line. Don't try window line and expect to get their results. Understand what 'open wire TV line' actually is, and try to duplicate that. Don't even consider any line other than true ladder line. '300 ohm TV twinlead' in particular would be a disaster. BTW mine was about 25ft on a side. They have been built to 50ft per side, but all the matching network component values change. The bigger loop would deliver more output on 160m. If you have somehow missed it, here's my online page on the K6STI loop: http://www.angelfire.com/md/k3ky/page45.html I have continued to get a slow but steady stream of inquiries about the antenna, over the years. 73, David K3KY ___ Remember the PreStew coming on October 20th. http://www.kkn.net/stew for more info.
Re: Topband: Vertical dipoles in the real world
http://www.qrpdx.com/ant.html I think these are a great idea for simple, inexpensive directivity. I'd like to throw in the idea of trying this with a Moxon beam. As a horizontal antenna, there is no doubt the Moxon should deliver superior F/B compared with a classical 2el DE/Dir or DE/Ref Yagi. Perhaps this would also hold true in the vertical orientation. But an equally important benefit is the significant length reduction with the Moxon design. The folding makes a 40m beam looks quite doable... I'd like to hear ideas from others as to some good, simple, lightweight designs for a rotary slip joint to be used to suspend the antenna from- one which resists ice formation in winter. A simple rope suspension can freeze up solid and refuse to turn. BTW You can put a ground-mounted rotor on these. Alas, these antennas are unlikely to be seen much on Topband, but with this ham DXer community, you never know... 73, David K3KY P.S. Yes, they will work way better by the ocean. Yes, you're throwing away up to 6dB reflection gain by not running it horizontally. See Moxon's book "HF Antennas For All Locations" ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: 4 new radials...
Hi, Jim- Remember, when you transmit, those radials are radiating. Worst case, you might even get arcing from any unlucky voltage points along the 'radials' depending on power level and the actual lengths. And those wires are in your neighbors' basements? Yikes! They could possibly tear up AM radio reception, Hi-Fi in general, cable and DSL modems, etc. Your situation would make me nervous. Even 100W levels might interfere with your neighbor's electronics. Sorry, don't mean to rain on your parade, but this could be problematic for you. I guess it wouldn't hurt to try... 73, David K3KY ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Topband: K2AV Folded Counterpoise- More Transformer Questions
I echo W1FMR's question regarding possibly substituting a T200-2 core. Personally, I'd double it up, i.e. either a stack of two T-200-2 or else a T200A-2 which is 1.00 inch thick vs. 0.55 in. for a T200-2. My guess is that the power handling would be less than a T300A-2? But what about smaller #2 cores for QRP? Provided you do choose combinations with the same A sub L, you might expect similar winding inductances/ reactances? I don't know about effects on Q here, but I suspect that is not an issue? The A sub L for a stack of two T200-2 is almost identical to that of a T300A-2. My own question regards which exact types of enameled 14AWG wire might be acceptable. I know the double polyimide type is very rugged with good HV breakdown. OTOH there is so much insulation with those teflon sleeves that I'd think it would be OK to use most any type of enameled 14 gage wire? Or even bare wire? Would it make all that much difference in overall HV breakdown ratings? Since this is a classical transformer, and not a transmission line type transformer, I would think that the characteristic impedance of the windings would matter less here? What if the builder had on hand some 14 AWG silver stranded teflon wire. That would also fit in the large teflon sleeving I have here, although a little snugger. What might happen to the performance with that one design change change to the wire type? If I can get away with it, I may initially try a stack of T200-2 cores- but if the bigger T300 size is truly essential, I'll get one on order. BTW the most I'm usually outputting here is more like 800-1000 watts. I'm sure the T300 size is a much better bet for a full 1.5KW. 73, David K3KY P.S. I recognize that Guy would prefer to eliminate variability and thereby accumulate some group experience among a user base. Standardizing on the T300 type transformers would be a very good idea in that regard. OTOH hams can be frugal, hams like to experiment, and hams will often want to try to adapt designs to what they have on hand. There is a natural tension between those two things. ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: Counterpoise very interesting
In retrospect, I'm asking myself "was this thread a troll?" I can't tell who the sender is- no call, signature, etc. Could this be bashing calling the FCP a 'counterpoise'? Well, regardless, it's not going to deter me from trying one. 73, David K3KY > Original Message > Subject: Topband: Counterpoise very interresting > From: > Date: Mon, November 21, 2011 9:28 am > To: > > > http://www.antennex.com/shack/Dec06/cps.html > ___ > UR RST IS ... ... ..9 QSB QSB - hw? BK ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: Counterpoise very interresting
Cebik's paper on the counterpoise is interesting and perhaps useful, so far as it goes. I don't remember seeing any mention of voltage-fed antennas, however. If they are in that article, I missed them. Cebik mentions Woodrow Smith in connection with a 1948 antenna book. I don't know if this is the same 'Woody Smith', W6BCX, but I suspect it is. Woody Smith wrote an article in March 1948 CQ Magazine titled "Bet My Money on a Bobtail Beam." In that article, he is somewhat vague about the ground return for the center element, but is very clear that 'not much' of a ground is needed. In his Feb/Mar 1983 HR Mag. reprise of the Bobtail/Half Square antennas, he refers to the desirability of a 'ground screen', refraining from calling this small, rectangular grid a 'counterpoise'. But that's what it is, in today's usage. I called it that in my Bobtail pages, and will likely continue doing so. http://www.angelfire.com/md/k3ky/page49.html Moxon, G6XN also refers extensively to the counterpoise in his favored half wave vertical antennas, and in his case, is talking about a pretty tiny piece of metal indeed. See" "HF Antennas For All Locations." by G6XN. Cebik tended to be pedantic. Heck, he was a college professor- duh! He certainly knew his stuff, but his views were not necessarily global at all times. Perception colors our understanding of the world. Language is a living, growing thing. Cebik was probably right about the concept of the counterpoise having been 'muddied', but OTOH that horse is now long out of the barn. I very much doubt the word is going away any time soon, in ham 'circles'. Or squares or rectangles. Even elongated, skinny rectangles. I find K2AV's FCP (folded counterpoise) most intriguing, and I intend to give it a try here. My inverted L needs help. I am so over with crummy 'sparse radials'. What a waste. Also, I intend to shift more towards a longer L which more approximates voltage feed. Having a quarter wave L with the current point at ground level is just asking for poor performance IMO. 73, David K3KY ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: contesting in a field
I like resonant, voltage-fed verticals for their simplicity. For field ops, they can be a very quick way to deploy a working antenna. On 40 meters, for example, you're only dealing with 70ft- or 35ft if bent like an "L", Half Square, Bobtail, etc. If you could catch Murphy on vacation, and if you can raise a large enough balloon to support ~268ft of smaller gage wire, you can go with a voltage fed half wave using an LC tank to tune it. Tap up the coil from the ground end with your coax for a 1:1 SWR (assuming your LC is properly resonated) Your farm isn't near any airports, is it? OTOH if it's windy, this could be a rather frustrating event. (technically, you're 'pushing it' a little with anything over ~200ft in height) You don't need much of a counterpoise, feeding this way- roll out however much chicken wire or wire cloth as you care to- or think 'radials', if that is your preference. A denser, shorter radial field or counterpoise ought to work pretty well. Having the current max up 134ft couldn't hurt. It ought to play reasonably well. As always, more ground is better ground. I like the roll(s) of chicken wire approach. 73, David K3KY >The last thing I need is a reason to generate flammable gasses in bulk :) > >We homeschool, so maybe that would fit the stereotype everyone expects. >"And then they did a chemistry experiment and blew up their garage." > >I've thought about an inverted L at home, I have just short of an acre, I >think the above ground part wouldn't be a problem its the radials. I'm >assuming in the wide open spaces at the farm I can pursue the same elevated >radials I would for a kite/balloon vertical? The elevated vertical thing >seems to be the best bang for the effort, and in some ways less effort >especially for temporary ops like this. Chris ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
