Re: Topband: CY9C
http://lists.contesting.com/archives//html/Topband/2024-09/msg00044.html Jim K9YC is 100% correct. With the US FWS making it nearly impossible to activate some of the Pacific islands, the RIB is or should be welcome. I don't chase DX or have any interest in awards but I can understand the significance and am perplexed as to why anyone would be against it, unless he has some rare island confirmed and doesn't want anyone else to get it. Any pettiness like that is what should be lamented. One correction: Sears Tower has no combiner. Hancock yes, Sears no. Deals for Sears fell through years ago and everyone went their own way on the roof. 73 Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: B7P
>It must be that there aren't very many BY hams that live in rural areas with >low noise floors. Hopefully portable operations with verticals on the beach >will catch on there. They need to get phasing boxes and figure out how to use them -- those things can't fix everything but they can clear out a frequency of one overwhelming noise source if it can't be controlled any other way. Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: INV-L Radiation Patterns: 15 years of experiments with one
50 foot high inv. L here; total length 120 feet; 101 radials on ground, but lengths vary from 10 feet to around 100 feet with most in the 20, 30, 50 foot lengths. Also I have an aluminum sided garage that I strapped into the ground system. Minimal reactance is at 1840 (I forget, but I think around 10 ohms). Real component of the Z on that frequency is 11 ohms. Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: Inv L Radiation Patterns?
A bit more field intensity extends in the direction opposite the direction of the horizontal part of the inverted L element. 73 Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: Using 4 - 6 elevated radials in lieu of 120 buried wires
>The radial height above ground clearly did not need to be 50 feet,. It did >need to be high enough to easily be well above a tall truck, or more commonly, >a horseback rider. The advantage to this is that you can get away with wire composition (copper clad steel, or even aluminum if handled properly) that would not hold up on or under ground. And obviously, less wire is needed. The fly in the ointment is that as you and K9YC mentioned they have to be seriously elevated. The clearance for a vehicle may matter but the real reason is antenna physics in terms of wavelength. Radials on the ground act like a shield between the vertical element and earth. When you go elevated, the radials become a counterpoise and the antenna takes the form of a distorted vertical dipole but for that to happen it has to be sufficiently removed from earth influence and that's a matter of wavelength. That's why on 160 m. they have to be high -- what I've heard is 1/10 wavelength but as mentioned, things seem to go well starting at around 20 feet. Since it's more like a distorted dipole, the length of the radials matters and they have voltage on them. Their spacing should be equal. So, as usual with antennas, there's no free lunch. I occasionally work someone with an inverted L and "elevated" radials which turn out to be around 8 feet high or less. Sorry, but no, not even close. But I've quit trying to teach these guys because they believe what they want to believe. 73 Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: NCC-2 antenna pattern?
Since I am on a 50 x 100 foot lot, it is impossible for me to separate my rx antennas from my tx antenna. Of course on transmit, preamps and the NCC1 are deactivated, but even so, the NCC1 had internal relay chatter (there are around nine PC board mounted relays inside). Small RF chokes in series with the DC power line to the box eliminated the chatter. I may have added bypass caps inside it but I can't remember if I did that or not. But if so, that wasn't enough. The chokes did the trick. Merry Christmas Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: AM Broadcast Filter recommendation
First, get some kind of portable receiver out and put it on 1820 and verify you are hearing the harmonic. I doubt it is being generated in your gear. You will probably hear it because you are only 2 miles from the tx site and if the station is running 5 or more KW they're likely suppressing the harmonic adequately -- you're simply too close. What we often hear in our own stuff like preamps is products generated by a pair of broadcast stations mixing. This doesn't mean that a broadcast station is never at fault. Investigation shows your problem station is a 5 KW directional with 3 or 4 towers depending on the pattern. https://radio-locator.com/info/KRIO-AM There's more to go wrong there. You should look at the night pattern and determine if your station is in a lobe or null. You can observe if the harmonic strength varies from day to night. It's true that AM stations aren't getting maintained as well as they once were. Problems can crop up in the station's phasor, and tower matching networks. The pattern may not be in specification or they may not even be changing to the night pattern. A lot of high pass filters do not attenuate well near the top of the broadcast band so as to not compromise 160 m. performance. So fellows with stations nearby that are on 1500 or higher: Choose your filter with care. In the case of 910 you have a wider selection from which to choose because just about all of them will knock a low frequency like that down. Even if the problem is a harmonic, putting in one or more filters is worthwhile. What about the harmonic? If it's coming from the station, all is not lost because it is a point source. You can receive with small loop antennas oriented to put the harmonic in the loop's null, or better, employ a phasing network using inputs from two separated receive antennas that can throw a null on 1820 at the offending broadcast station. Or you can use both methods. If you are happy with your current receive antennas, I'd try a phasing network if all else fails. 73 Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Topband: ICE Model 135B Preamp
>How do you operate QSK with that kind of setup ? I don't operate QSK but I am sure there are QSK ways of protecting preamps. This is a question for the QRO CW DX folks. Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Topband: ICE Model 135B Preamp
On those ICE preamps, check the small dipped inductors, because they can blow open if the preamp is exposed to a high enough RF field. If your preamp is on a rx antenna and you are transmitting with ham QRO nearby that's enough to do it. IIRC powering down the preamp isn't enough. It has to be behind some kind of feedline relay that opens. 73 Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: Digiwave feedline
Okay thanks for the explanation. Rob K5UJ > Depends on the efficiency of the antenna and whether there's a preamp at > the feedpoint of those with low efficiency. It doesn't matter for higher > efficiency RX antennas like Beverages, or where local noise levels are > fairly high. And it doesn't matter if there's a preamp at the feedpoint. > Mostly it can matter for TX antennas. > > 73, Jim K9YC > _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: Digiwave feedline
>Al shields and CCS centers can be fairly lossy below VHF. CATV coax tends to >be much cheaper than the coax designed for transmitting, thanks both the the >lower cost construction and the extremely large market for it. Does this mean we are better off using something like RG8X with copper shield and center conductor for lines to low band rx antennas? 73 Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: Topband cw - bugs rhythm, swing
There were a few electronic key designs that surfaced in the '50s, maybe even late '40s, usually appearing in QST. But then Jim Ricks W9TO designed his TO Keyer which Halicrafters started manufacturing and that pretty much ended the other designs such as the MON-KEY. Vibroplex made a single lever paddle, the Vibrokey, in colors to match the TO Keyer and the combination was and is unsurpassed in my opinion, if you want a fully automatic key that feels like a bug. I never liked sending with a straight key and not long after I was first licensed I found a J-36 at a hamfest and stuck with that for years. I tried an iambic keyer and paddle set around 20 years ago and never really liked it. Then I fixed up a used TO Keyer and Vibrokey paddle and felt like I'd found a fully automatic bug, to me it was wonderful. A friend sold me a spare Original Deluxe a few years ago and I think that model is the best bug you can buy. If you look at old photos of commercial radiotelegraph operators, they're usually using Original Deluxes. Sadly, I don't operate CW much at all now and lately have been wanting to get back into it because believe it or not, I think it might help stave off dementia. Sending and receiving CW, if you don't use any gadgets to copy, uses your brain a lot more than yakking into a microphone. Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: AM broadcast multiplexing
I am always amazed at the hams who will buy a home within sight of a broadcast tower. Rule no. 1 when looking for a new QTH is to find where all the AM and FM plants are and avoid them; especially QRO AMs vis a vis 160 and HF. I remember looking around the 670 site in Glendale Heights IL around 10 or 15 years ago, just to get a look at the tower, guying, base pier and insulator and so on. This is a 190 degree stick so we're talking around 800 and something feet tall. Then I caught sight of a short free standing tower behind a house with what appeared to be a TA33 on it, maybe half a mile away. I know that ham tower was not there before the 670 site was built. I just shook my head in bogglement. Not sure if that's a real word or not but you know what I mean. Maybe he got a really good deal or his XYL insisted on it. 73 Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: How good is good enough
>Just cut 20 more 70' radials. Time to go play in the yard. If that were all I could add, I'd switch them to 40 35' radials. The R component of my inverted L on around 1840 is 11 ohms. X is around 20. That's with 101 radials. I look for a R of at least 15 ohms where X is minimal on an analyzer sweep. At that point the ground system is getting good. The vertical part of the L should be at least 50 feet.Just ground the analyzer and put the vertical element right into it. 73 Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: Skirted vertical antennas for MF broadcast
>I'm surprised that the broadcast industry is just discoving [sic] this topic. What makes you think it is just being discovered? Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Topband: What antenna would you build?
Good question. I don't think you mentioned any cost limit. Given that I would put up a substantial self supporting commercial tower ~ 130' tall. Solid legs, 5 or 6' face tapering to 1 or 2 feet. Pyrod or similar. I'd put a skirt on it, 3 vertical wires on insulated standoffs with horizontal loops bonded in, every 20' or so and plow in at least 100 quarter wave 160 m. radials around the tower base. Essentially a skirt fed 90 degree monopole on 1800 kc. skirt feed means the tower can be grounded and used for other purposes at the top -- whatever your interests are. Of course it would have to be sited to allow room for the ground system. Forget about anything horizontal or any kind of dipole on 160. I guess if you wanted to spend a lot, you could do a pair of these towers and phase them. You'll have solid towers you'll never be hesitant to climb; and never have to deal with guy cables, or a base insulator like you'd need with a guyed hot tower. You will get out unless the band is completely dead. It will be interesting to read what others come up with. 73 Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: TV coax + F-connectors
Good luck with that voltage breakdown rating for foam RG6 running high power through it and other than a flat line. As to the milliwatt loss on transmit, okay FB but on rx with microvolts, I'm already deaf and don't need for it to be any worse than it is. 73 Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: F connector how-to video
I know many will disagree but I wish the ham industry had never gone to RG6 and F plugs and jacks for filters, preamps and various rx antennas etc. I know that UHF/BNC/N take up more space and cost more but the feedline and connector series that works for broadcast TV, cable and broadcast FM reception doesn't always have the benefits hams need, in my semi-humble opinion. There is a confusing variety of connectors and cables, strip and crimp tools, and quality is all over the place, I think aluminum shields and crimps are unreliable, and I don't think this entire line was ever originally intended to carry DC to power active devices. I much prefer copper and soldered connections, plus BNC/UHF/N males can be threaded on and hand tightened or released with a quick plier assist, and there is no reliance on a thin copper plated center conductor for the male pin. The whole move to RG6 and Fs was a big mistake. Okay for consumer TV sets and other throw away junk but not ham. I realize there is garbage RG8 and 8X and UHF connectors but they are a lot easier to spot and avoid. The convenience of solderless cable prep outside is great, but where are you when a few years later you have all kinds of intermittent problems out there? Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: Radials on ground v FCP
I can't comment on the folded counterpoise because I am not familiar with it. The "broadcast model" which I take to mean 120 radials is used because in the case of a 90 degree tower on medium wave, the earth current intensity is far enough from the feed point to necessitate a higher number of radials so that as they diverge, they are not so far apart from each other that the earth losses are unacceptable. Few hams have 1/4 w. towers for 160 m., and instead employ shorter vertical radiators such as inverted Ls* and Ts, (1/8 w. for example) so the ground current intensity is high much closer to the feedpoint. This means that fewer radials can be used because they are shorter and at their ends, are still an acceptable separation from each other. Of course, ground conductivity plays a part also. This is good news for hams who want to save money on expensive wire. All of this is detailed in the Griffith book I referenced previously. 73 Rob K5UJ *Unlike the T, the horizontal portion of the inverted L radiates. W1BB recommended extending radials that run along underneath it if possible, and I think that was good advice. On Sat, Jan 8, 2022 at 9:27 AM CUTTER DAVID wrote: > > Rob > > I recall a discussion on here some years ago which proposed that, whilst > being an amazing antenna for top band, if you could achieve it, the broadcast > model was not necessarily the best use of resources for amateur purposes, on > the basis that broadcasters are mainly interested in ground wave to cover a > defined relatively short range service area, whereas amateurs a more > interested in dx. > > I don't recall how that discussion ended, but for purposes of saving wire, at > least, the K2AV folded counterpoise (FCP) must be about as good as anyone > could attain. How it performs against that broadcast model would be of > interest. > > David G3UNA _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: Radials on ground
For medium wave, every ham who transmits with a base excited vertical radiator should get a copy of _Radio-Electronic Transmission Fundamentals_ by B. Whitfield Griffith, Jr. 2nd ed., Noble Pub. Co., Atlanta Ga., c2000, ISBN 1884932134. 638 p. Griffith is a retired principal engineer with Continental. This classic college broadcast engineer textbook explains many fundamentals involving medium wave transmission in an easy to understand way. Getting the most out of your valuable copper wire is more important now than ever because copper has risen to insanely high prices. The book is probably out of print but might be available used from ABE Books https://www.abebooks.com/ 73 Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: Need antenna help
The problem with adding a top wire to your 43 foot vertical is that it is probably not made to support a wire pulling on it at the top, unless it's cross section is uniform and it is guyed at the mid-point and top so it doesn't pull over. What is often done in this situation is that a trap is employed at the top between the vertical and wire so any RF above 160 m. doesn't make it to the wire. That was the HyGain HyTower 160 m. add-on kit design. Or, you can use the 43 foot vertical (if it is strong enough) to hold a separate wire on insulated standoffs for 160 and feed the wire at the base for 160. I do that with my 1/4 w. 80 m. vertical; the inverted L wire is about 3 feet out from the 80 m. mast. To be honest, I recommend something like that for 160 and 80 m., over the same ground system, with some other solution for 40 on up. I'm not a big fan of the 43 foot vertical which has some strange fascination for many hams. 73 Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Topband: Horrendous Local Noise
>Well he drove the 100 miles up here and arrived with a colleague about 2pm, spent a while in the shack listening to the noise, and monitoring it on their equipment connected to my Top Band dipole. After about 45 minutes they both went out in the street, and an hour later they came back to say they >think they had tracked it down. >It actually turned out to be a faulty piece of equipment in a house up the street . . . but not radiating directly - it was sending these huge spikes back down the Mains . . . and then I guess the wiring in all the houses along the street was then re-radiating the noise (which is why I couldn't DF >it properly). The key thing is a transformerless appliance that puts noise onto the power line from the utility and is reradiated by all above ground wiring that is directly connected to the offender's service drop. Here in the U.S. that would be every dwelling on the secondary winding of the distribution transformer. For the average ham, this would be almost impossible to locate and deal with directly. You found how difficult it was. Therefore, it would be extremely useful to find out what the officials did to diagnose the problem. What did they think when they heard it? What detail about it stood out to them? What apparatus did they use? Exactly what did they do to track it down? Once they found the source, what did they tell the homeowner? Was the device replaced? Confiscated? Were they ordered to stop using it? And what was the appliance? Folks, don't just let these opportunities to learn go by. These are valuable opportunities to become better educated so some of this work can be done by us to save time. 73 Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: cheap radial wire?
> Dog electronic fence wire via ebay. Bad idea, except maybe for field day or some other temporary setup due to rust. Also, long thin runs of steel may not return RF well. For permanence it's a lot better to invest in 3000 feet copper that can provide sixty 50 foot radials. That will at least get you in fair shape with an inverted L. But, I get that copper price is out of sight now so if you don't mind wasted effort, experimentation with cheaper alternatives might be worth it. Just be prepared to have them rust away or vanish in the case of aluminum. It might be advisable to find out about your soil acidity before doing anything. Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: Balloon Supported Vertical
I'd look into some kind of drone for this. Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: Anyone using a NCC-1 with 2 magnetic RX loops?
I have a NCC-1 with a pair of rotatable pixel loops. I have one filter in the NCC-1, a high pass broadcast band filter. It really hits the stations around 1000 and below. Doesn't have much attenuation near the top of the band but the problem stations are down below 1200 here (Chicago). 73 Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: Inv L corner insulator
My hunch is that your problem is the wire you are using. My inv. L is strung with hard drawn 7 strand bare AWG 14 copper. Multi-strand or solid soft drawn will probably break on you eventually. 73 Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: Question on active vertical spacing
My rx antennas are around 40 to 50 feet separated. I get good peaks and nulls on 160 and the top of the AM broadcast band. 80 m. doesn't work as well. But 160 is where you really want it to work. That's where noise is a big problem. Use a groundwave broadcast station on 1400 or higher to test your setup and practice using it. It helps if you have some kind of receiver with a panadapter. As you rotate through the phasing you can see the broadcast carriers move up and down. Using phase and balance between the two antennas, you should be able to take a pretty strong carrier and put it into the noise. 73 Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Topband: RX loop antenna RX protector
You probably have a preamp on your rx loop. The first thing to do is kill the dc to it on transmit to shut it down. I have an Airspy HF+Discovery SDR which has a fragile front end. To keep tx RF out of it, in addition to shutting down the preamps, I put a pair of coax relays in series, the little ones with SMA jacks on them, between the antenna feed and the SDR. I used a pair because each had 12 v. coils, and my sequencing system runs on 24 v. I also put the SDR in a metal box and put pie wound chokes in series with the DC control lines into the box. As I recall, that was enough to protect the SDR. A lot depends on prox of tx antenna to rx antenna and also tx antenna relative to shack. If all are spread out, job is much easier. I also used an ice cube relay in the feedline to break open both the center conductor and shield to interrupt RF on the outside of the shield. I looked at the commercial rx protectors (not the one posted here by a fellow in the U.K.) and the specifications were not sufficient for the Airspy. Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: Shunt-fed Tower Ground Ring Insulators
Tower base concrete should not be in series between the tower and ground. There should not be a voltage gradient across the concrete base. All ground paths should be strapped around the concrete base. 73 Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Topband: Hygain hytower on 160
No personal experience but I've heard repeatedly over the years that the inverted L kit works way better than the loading coil. This makes sense. I think the inverted L kit consists of a trap you hang off the top of the BX section. You probably supply the wire but on that I'm not sure. I don't know if this kit is still being made or not but you might be able to fabricate a trap yourself. Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Topband: NCC-2 for phasing RX antennas
If you are having a problem it would be faster if you wrote what your problem is. Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: Adding 80 m to 160 m quarterwave vertical
A ham can certainly try a voltage fed 180 degree vertical, but the physical conditions at the feedpoint change dramatically because it's quite possible a few KV of RF v. will be there, unlike what we have with a current maxima at the feedpoint. So insulation and keeping surfaces dry become much more important. You can't just use a block of wood exposed to rain for an insulator and if the base is on a concrete pier, it has to have copper strapped around it so the concrete isn't part of the v. gradient between the antenna and ground. Besides arcs, RF loss is a consideration, plus the ground system has to be extended because the induced earth currents are farther out. It's a lot of trouble and expense for a slightly lower take off. 73 Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Topband: Elementary Inverted L questions
>I have been trying to replace my inverted L, which broke a few weeks ago, and >am having all sorts of puzzlements. Please be kind - I was a history major. 1. > The inverted L broke at the turn, so I went looking for sturdier >wire. I >wound up with some #14 insulated recommended by our local RF maven, I advise ordering a roll of number 14 bare, 7 strand hard drawn copper wire. Put up a continuous length of it. It will be less likely to break. On-ground radials can be solid soft wire. Not the vertical. > and put up 140 feet initially, figuring I would prune it *up* into the CW > part of the band. Imagine my surprise when it showed up resonating at 1977 > KHz (on an AA-55 Zoom). Your plan is okay, but something is causing a problem. Firstly, you need to putdown more radials. > Does insulation have such a profound effect on velocity factor? 2. My > feedpoint arrangement has 17 turns of RG-400 as a common mode choke, with the > radial field connected to the RG-400 shield at the antenna end. Ditch the choke and put your measuring instrument right into the driven wire and ground system.If you have 60 or 70 radials, you don't need that stupid choke. > Initially I tried measuring the resonance without the radial connection. No > resonance and infinite SWR. I connected the radial field (8 X 70-foot > radials on the ground) and that's when I saw the 1977 KHz resonance (X > crossing zero). SWR at minimum was above 2:1. Does this make sense? I know > the radial field is inadequate for good performance, but... The vswr only 2:1 makes sense because you have a poor antenna. It should be 4 to 5 to one minimally on some frequency on an analyzer that is normalized for a 50 ohm load, IF you have a decent ground system. With few radials Z is higher up and closer to 50 ohms instead of 10 to 15. This also depends on the vertical height. I'm assuming a typical inverted L that's around 50 feet vertical. Analyzers put an extremely low amount of power into whatever they're testing. The highest power unit I know of is the MFJ 259 family which puts out around 20 mW. Poor continuity such as corroded surfaces at hardware joints or cold solder joints or contact surfaces such as banana plugs and jacks will be high enough R to throw off the instrument. Put 100 w. into the antenna for a few seconds to blow through these problems and check it again without the choke. Ideally an RF source should not fold back. The old Ten Tec rigs were good for that. Better still is a tube rig like a DX100. It will dump 100 w. and not give a flip about the load Z. Hit it for a second or two with whatever you have. The excited wire may be broken, or ground system bonding flawed, or something else. Example case: I have an inverted L 50 feet high that's held up with a guyed 3" o.d. aluminum mast that's 50 feet high in two sections. The mast has one point at 31 feet where the sections are bolted together and guyed. The top 19 feet is free standing. Naturally there's some interaction between it and the driven inverted L wire. When I put it up, I stupidly neglected to put Noalox on the joint at 31 feet. Now, on extremely windy days and nights, the mast bends and flexes and that joint becomes intermittent. This affects the inverted L Z. My L network matches the antenna to 50 ohms under normal conditions but when the wind gusts up continually to 50 mph or more, I see the vswr jump up to 3 to 1 roughly, as if a switch is being flipped. I have to tilt the mast over and disassemble that coupling, clean and reassemble it with Noalox. 73 Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: Ground Radial question - Perimeter connections
It depends. If you have two or more verticals for a phased antenna, and full length radials, the points where the ground systems intersect is where the radials should be terminated and bonded to copper strap running along the boundary where they cross each other. If you have an out building in the radial field, a strap is usually run around the foundation of the building, radials run up to that and bonded to it, then continued on out on the other side. These are methods prescribed in broadcast engineering texts, and what you'll find at a commercial ground system installation. If you have one vertical and a ground system for it, you don't need to do anything. Some professionals terminate compromised lengths (i.e. < 1/4 wave) with short ground rods or strap but I am not sure there is any real benefit to that. If it were me, I'd put my money and effort into more radials rather than perimeter strap. 73 Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: New Subject: 160M array feedline question
Inspect your feedline you plan to use (sounds like it is Heliax) and make sure the jacket is undamaged. If it is okay, you can bury it or just lay it on the ground and it won't matter if water covers it. Of more concern is keeping the junction where the feedline divides dry. If you use enough radials, you won't have to worry about the feedline shield becoming a radial. It will be one, but the RF on it will be minimal because it will be one among many radials. But you have to have a lot of radials. I am taking your description of the field being under water for only a couple of weeks a year into account. If you are concerned about animals chewing on the line, burying it or elevating it may be needed. I've had something chew on my 1/2 inch line but I guess rodents realize the jacket isn't the same as wood so they don't go very far. The line is fine due to the solid copper shield. This is one of the reasons why Heliax is superior to braided shield line and a worthwhile investment. 73 Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: New Inv-L Questions
To clarify: > The sign your antenna is efficient will be a > narrow R and X sweet spot. R should drop down to around 14 ohms and > (depending on the length of the driven element) X should hit zero over > a few kc. I should have written: X should hit zero over a few kc at some point in the band, depending on the length of the driven element. Sorry for the confusion. 73 Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Topband: New Inv-L Questions
> My questions are these - is a > relatively flat curve to be expected, or a sign of something wrong? A flat curve is to be expected and it's a sign something is wrong. And that something is that you do not have nearly enough radials in your ground system. Your radials are on the ground. Such a ground system should be augmented with about 10 times the number of radials you have, but they don't need to be 70 feet long. 50 feet is okay, but you need many more. The sign your antenna is efficient will be a narrow R and X sweet spot. R should drop down to around 14 ohms and (depending on the length of the driven element) X should hit zero over a few kc. If there are structures around re-radiating you may not see 0 X; it may dip down but not get to zero. 73 Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: The WD8DSB mini-flag antenna
Bi-directional loops lose their directivity for the most part, when being applied to skywave signals. Is this mini-flag still unidirectional on skywave? I would think not, but must ask. 73 Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Topband: 160 Receiving Loops source?
How much is "affordable?" I mean, if you pay junk money, you'll probably get ... disappointment either right away or after a few months. A possible exception is some place warm all year with no broadcast stations nearby, so fixing and improving any time is easy. OTOH if you are in blizzard country, a budget priced loop may decide to quit working during snowmageddon. Consider a sturdy mount too. BTW, while I'm dispensing free advice, if you power your loop preamp via the feedline, use some sort of copper coax that can be soldered. The RG6 aluminum stuff with crimp males will fail eventually -- okay for RF but not DC. Eventually there will be just enough corrosion at the surfaces where the crimps are, that you'll get just enough v. drop and the preamp won't come on. For RF and RG6, it is important that you get quad shield (yes even on 160) and make sure the males match the coax. The crimp tool, connectors and coax should all be made to go with each other. One trick is to look for a cable TV guy who's out on a job with a truck and approach him. My experience is that they don't mind talking for a few minutes about their tools and materials after you explain why you are interested. Find out what he uses for "drop cable," crimper, prep tool, and plugs. Companies like Comcast don't use junk. Then go get what he uses. 73 Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: S meters
I estimate that my receiving loops are 20 or 30 dB down from a full sized antenna such as a 1/2 wave dipole at 50 or 60 feet, an antenna that a lot of casual operators use (often to their detriment) on 160 m. Sometimes I'll just add 30 dB to the S meter reading. Alternatively, I'll tell the guy I'm working that I am either using a speaker or headphones to hear him and with the latter, what % of his transmission I copied. Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: Cage wire performance
The problem with cages isn't electrical; the thing to consider is physical. If you are in an area where you can have ice you have to consider if your cage and its supports are strong enough to hold ice under high winds. You don't want a relatively inexpensive wire cage to pull down more costly supports that are a lot harder to rebuild. Good idea to build in a weighted antenna that will sag to the ground under a lot of ice, or a fail safe that is easy to fix. 73 Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Topband: standoff for inv L
I've used a PVC pipe around 1.5 or 2" o.d. and ~ 3 feet long, for the past 11 years. No problems so far but it is braced with dacron from the insulator end, back up to the mast a few feet above where the PVC is clamped to the mast. Mine is unprotected from sun but the sun exposure is less in the Chicago area. Of course when it eventually fails, it will be in January, hi. If I had it to do over again I would have used the gray PVC that is supposedly UV resilient, and taped over it as K9YC suggested. Mine is hung the same way--wire through dog bone insulator on rope through pulley, pulley attached to PVC. I'll bet that an aluminum pipe would work okay since the wire is well isolated by the insulator, rope, pulley, rope series but use dacron not wire and a decent insulator. 73 Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Topband: Low Dipoles
> I do take offence at people suggesting that I am somehow lying about the > results I have always had with a 160m Dipole at 50ft ! I don't think anyone believes you are lying, but perhaps instead, that you seem to imply that your experience can be generalized and that you are therefore, misguided. This is because your results run counter to decades of experience and observations by countless others when it comes to antennas and 160 meters. I invite you to come to the middle of North America, Nebraska let's say, and set up the exact same antenna in a rural location and report how it performs after a full winter operating season. Merry Xmas Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: I need help proofing an Inverted L model I made please. 40
> IMHO, for that number, on-the-ground radials do not need to be anywhere near > that long. Personally, I subscribe to the same-length-as-the-vertical > guideline. The only thing about this I advise in the way of a change is something W1BB recommended, which was that the radials on the ground going out underneath the horizontal L wire should be as long as the horizontal wire. My horizontal component has some bends in it and I routed around 10 radials under it to follow it. It probably doesn't make much difference, but it isn't that hard to run a few that are under the wire all the way out. 73 Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: I need help proofing an Inverted L model I made please. 40
I've never understood what is gained by using a balun at the feedpoint in this application. The feedline is unbalanced as is the load. What's the point of a balun. The wild variations in R and X over the range of the band will likely result in heat and loss at the balun. If the point is to keep RF off the exterior of the feedline, that problem vanishes if you have a lot of radials which are needed regardless. The best solution is to put the matching network at the feedpoint but if you opt to match the line to the transmitter at the shack, the vswr loss for 70 feet of 213 won't be terrible and the dielectric will probably withstand the voltage maxima. 73 Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Topband: Good valve homebrew rig
Are you sure you want to homebrew a vacuum tube _transceiver?_ How about starting with a separate transmitter and receiver? A tube CW transmitter for 160 is certainly feasible. A transceiver is too in theory at least, but kind of a tall order. If you pull that off, you'll certainly have my unending admiration, but I for one can't recommend anything. A transmitter is different. What power level do you have in mind? 73 Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: Stainless Steel for coil taps.
> There was also some mention to the effect that nickel was > a "non-ferrous" metal and therefore would be good at RF. > Nothing could be further from the truth. Although technically > "non-ferrous", nickel is nevertheless "ferromagnetic". > I once measured some nickel strap material for RF loss > and it was horrific. Much worse than even what its DC > resistivity would suggest. This got me reading (https://en.wikipedia.org/wiki/Ferromagnetism) and I must state that I was mistaken about nickel, which of course is part of AlNiCo speaker magnets for one thing. I apologize and thank N6RK for this correction. The Wikipedia article mentions some types of stainless steel as being non-magnetic as I discovered by trial and error years ago (but even so s.s. has a lot of resistance as has been mentioned). Brass is also a poor conductor. I failed to mention that some metals such as brass in a tank circuit are okay as threaded fasteners but are not good for use as strap. If you routinely build or modify RF matching networks or run strap for grounding etc., it's very nice to have on hand a roll of copper strap, pair of sheet metal scissors, and a Roper Whitney Jr. hand punch. 73 Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: Stainless Steel for coil taps.
> Rob, are you implying that I shouldn't use a steel lattice tower to conduct > RF as a radiator? Good question and I wondered the same thing. Firstly not "implying" that at all. It comes down to mass and surface area. The problem with steel, iron, etc. is when you have a lot of RF current over a small area like a narrow piece of steel strap or a steel nut, bolt and washer. The surface area of a tower is so big that it doesn't present the same amount of problem. 73 Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Topband: Stainless Steel for coil taps.
We all learn this sooner or later: Don't use ferrous metals to conduct RF. If a metal fails the magnet test, it's out. Every time I get some item of homebrew or something that's had a previous owner, (transmitter or matching network) I go through with a magnet and see if a previous owner or builder used steel around RF stages or matching networks. Some steel alloys may be better than others but it's impossible to tell, so out they go. Brass, copper, aluminum, silver, nickel all okay. EF Johnson and perhaps others used steel nuts and bolts that were plated with nickel. That's okay as RF current has the skin effect. What's wrong with ferrous metals? They don't conduct as well but more important, at the microscopic level, they vibrate at the RF frequency. This does two things: Generate heat, and slowly loosen clamp, as in the case of a nut, bolt and washer for example. Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Topband: OT - Bonding Radials at Intersections
Scroll down to drawing 5 and 6 to see the proper way of handing intersecting radials. http://www.hatdaw.com/papers/groundsystem.pdf 73 Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: CW Activity
If you want to find out about QRN somewhere you don't have to ask on an email list. You can just go to windy.com or www.lightningmaps.org and see for yourself. Also lightningmaps has a gray line plot so you can see where dawn and dusk are. Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: Rohn 25 Vertical questions.
The proper way to use a tower like yours as a base excited monopole is to construct a pier of concrete with a bottom plate pin bowl that is steel and bonded to copper strap that goes down on each of four sides of the pier to the ground ring. The reason for this is so that there is no voltage gradient across the concrete. You need to obtain a Rohn 25 bottom tapered section and a porcelain Lapp or Austin insulator that has a bottom cap and pin that seats in the bowl. Now your tower is correctly insulated in a single point so it can rotate under wind stresses. The insulator should have all of the voltage across it in the event of a lightning strike, and you need to have a ball gap between the tower and the grounded steel pin receptacle on the top of the pier. Your tower should be guyed according to Rohn specifications, but the guys if steel, must be broken up with johnny ball insulators. If I were planning such an antenna I'd opt for a free standing tower, skirt fed with insulated standoffs holding vertical wires, one off from each face, and tied together with horizontal rings about every 25 feet of height. 73 Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: Windows 10 Update heads up
Seems to me that for the money hams pay Flex in that annual service fee, (or is it monthly?) you ought to get professional Windows maintenance. There are ex-MS techs out there who can be hired. I've had a Mac at home for the past 15 years at least. Since 2008 it's been a mac mini. So far, Apple has set it up so that I can choose between automatic and manual updates. I always have mine on manual. I get a notification when updates are available and then I pick a time when I'll install them. Macs have their share of nuisance problems and I am not heavily invested in computerized ham radio. If I had to depend on a computer for ham radio I'd probably find another hobby. Microsoft forces these updates because if they didn't millions of users would blow them off, and updates are vitally important for the security of your machine against outside threats. A lot of the updates have to do with patching vulnerabilities, many of which are immediately getting exploited in the wild. So many windows PCs have been hacked over the years the Company got serious about it beginning around 10 years ago and this is part of the result. 73 Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: 1610 KHz AM Channel in USA
Tnx for clarification. > I don't know what "noise is usually AM" means. Hi, I guess I was thinking of RFI from appliances and arcing contacts on power lines. 73 Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: 1610 KHz AM Channel in USA
>All of this success for BCB listening doesn't mean jack on 160 meters. >On the BCB, you are never fighting noise, rather just separating different >stations. They did also do that on 160 meters, for example, letting me >work JA's even when stateside stations were also calling me. I'm not following the reasoning here. How are listeners never fighting noise below 1710 kc? In some cases noise (or by noise are we thinking of QRM?) is worse on medium wave broadcast channels because noise is usually AM and so are the desired signals. Also the receiver passband is wide. Those TIS stations usually run only 30 to 50 watts and use physically small antennas. 73 Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: Adding connectoirs to CATV Hardline
For 160 m. frequencies, connectors on hardline that preserve the geometry (Z) of the line aren't needed. You can dress the line (i.e. strip back the jacket and dielectric) and make connections to transmitters and loads with copper strap that's wrapped around the center and shield and held with brass nuts and bolts or hose clamps. Use brass clamps if working with aluminum. 73 Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: 160m Vertical
On 5/15/2020 8:27 AM, donov...@starpower.net wrote: ""A more reliable approach is a tuner in your shack. The extra coax cable loss from elevated VSWR is insignificant on topband."" We don't really have enough information to make that claim. First, you ought to get a copy of Radio-Electronic Transmission Fundamentals by B. Whitfield Griffith, Jr. It is a standard college textbook for EE students interested in broadcast engineering and focuses mostly on medium wave and is easy to understand. We shouldn't advise you to put a matching network at the transmitter end of your line until you tell us what sort of feedline you are using, how long it will be, and what your transmitter power to the line will be. The wrong line with too much power over enough fraction of a wavelength, with a high vswr, could cause a dielectric breakdown. There's more to this than loss. 73 Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: BCB Filter Recommendation?
Most AM plants have been where they are for decades. I remember being at the local 670 site several years ago. That tx site has been there since the 1930s. This is a ~800 foot tower, now with two signals on it, 670 and 780, each 50 KW which means the total peak power on positive modulation is roughly 400 KW. I recall seeing a little 60 foot ham tower about a block away with a 3 el. beam on it, and wondering how any ham could be dumb enough to buy a house in the shadow of a major market ND class A-1 station.I would not even consider buying a house near a 1 KW daytimer. I'm about 10 miles from the 670 site and that's bad enough. Being a quarter mile from it would be a nightmare. 73 Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: Ground Conductivity
It is indeed true that variations in liquid soil moisture will dramatically affect ground system performance and base fed vertical impedance when an on, or below grade ground system is used. Frozen ground moisture is on a par with dry ground. This is one of the reasons for going beyond the point-of-diminishing-returns number of radials--the more radials used, the more stable the feedpoint Z is, over varying soil moisture in the radial field. Antenna efficiency is related to radiation resistance relative to the ground system. If you have a short vertical (inverted L) with a low resistance that you cannot increase, you can improve it by lowering the ground resistance by employing more radials. 73 Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Topband: Receiver protectors.
Last year I purchased an Airspy HF+ Discovery SD receiver. Eventually I got around to trying to use it with a second hand Windows laptop. I was concerned about blowing out the front end on transmit because I had heard of that happening with these receivers that are not designed exclusively for ham radio. A lot of the SD receivers are designed and manufactured by non-hams for lots of uses other than ham radio. They are not made to be used in an environment where they are in the near field of a transmitting antenna excited by a few hundred watts or more. I looked at the DX Engineering product and saw this specification: Max Output Level: RG-5000HD:+14 dBm at 10 W input. RG-5000: +10 dBm at 10 W input The corresponding specification for the Airspy rx is: +10 dBm Maximum RF input These are sensitive receivers. The DX engineering products were marginal so I did my own thing. I put the rx in an aluminum box with a UHF jack mounted on it an a grommetted hole for the USB cable's exit. I mounted a pair of relays in the feedline to the receiver inside the box and put RF chokes in series with the DC line to the relay coils (24 v. DC) at the entrance. I figured two relays in series in the line would add some protection. Amazingly none of this helped much as a 20 w. carrier on 160 m. produced a disturbingly strong signal trace on the receivers panadaptor. I wanted to see little or no signal at a few hundred watts to feel comfortable about operating at higher power. I was using typical ice cube style relays. The contact spacing isn't much so I think the relays were just acting like low value air dielectric capacitors in the line. RF went right through them. What finally did the trick were a pair of small DowKey style coaxial feedline relays with SMA jacks on them. Something kind of like these: https://www.ebay.com/b/SMA-General-Purpose-Relays/36328/bn_7684024 I found them at a hamfest and bought two because they had 12 v. coils so I figured I could put two in series with their coils in series for my 24 v. keying system. The same hamfest also had a guy selling small coax jumpers with SMA males on them. Perfect. I wired them up and put them in the aluminum box with the rx and all the other stuff. That did the trick. I see little or no signal on transmit and the SDR is safe at high power. I really didn't want to zorch a $170 throwaway item by making an avoidable mistake. It took a long time of fiddling and experimenting to get it right so I'm posting these notes to save others some time. 73 Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: Restoring the Signal to Noise Ratio
>This is only half tongue-in-cheek. >With the ambient noise going up, and there being limits to the size and cost >of receiving arrays most amateurs can build, the next logical step is to raise >the output power. Perhaps the FCC should be >petitioned to raise the legal >limit? They were supposed to safeguard our frequencies against interference >(man-made noise included), but since they have failed to do that, they should >allow more >power to restore the original signal to noise ratio? (Which some >already do, anyway.) It's a legitimate idea and probably one of the best ways of dealing with the problem when you think about what can and can't be controlled. I've been seriously suggesting the power limit be raised or eliminated for a few years now. Eliminating the power limit isn't as horrible as it sounds at first, because there are a lot of other factors that would prevent a ham from running crazy high power, but I don't want to digress off into that here. Unfortunately just raising the power limit is probably never going to happen. U.S. hams already have it pretty good compared to some other countries, and the RF exposure hysteria, which disregards the fact that about 99.9% of ham operations are harmless, would prevent it. Also, the power socialists who think everyone should be limited to 100 watts would jam FCC with objections. By the way, the power limit debate goes back to the 1930s; it isn't new, but the noise floor problem is relatively new. You can only do so much with rx antennas, phasing, DSP (which always adds distortion from my experience), filters and tx antennas. Of all the ham band allocations, medium wave is probably most in need of power. 73 Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: .TX Mica Caps
My opinion: the PCB scare is overblown, just like lead in paint, asbestos, etc. If you are intelligent about it, taking prudent precautions, PCB in caps and dummy loads should be fine. I'm sure hand wringers will weigh in with all kinds of nanny state far fetched what ifs, but I have PCBs around here and I'm fine. >-It catches on fire and fills the transformer vault with thick smoke when the >monster transformer melts down? At a ham station? >-When a few drops leak out of a filter capacitor in one of our radios or >transmitters? Mop up with a paper towel and drive on. >-If an electrician working on very big transformers puts his arm down in the >oil to make connections and does it for some years? I've heard of guys exposed that way and they were fine but again, that doesn't sound like a likely ham radio scenario. >-If I have a dozen 1000 and 2000 volt oil capacitors in a box in my barn? Usually these caps use a paper dielectric impregnated with pcb oil. What happens over time is that the seals around the lugs dry out and there's a gradual ingress of air which compromises the dielectric and the cap shorts out. Store them upside down or better yet, do a leakage test (methods for this can be found using google), use or sell the good ones and properly dispose of the leaky ones. >-If my want list has the RCA AR-88 on it which has oil filter caps? That set has a one-can three section filter cap bank made of of three 500 v. 4 mfd paper dielectric oil caps. In the transmit position on the front panel ("Trans") the high B+ can hit 480 v. with no load on it. That will usually cause those old oil caps to fail. The best fix is to buy 15 or 18 1 mfd 600 v. polypropylene axial leaded caps and make three clusters of 5 or 6 each and replace each can section with a paralleled cluster. Remove the stock cap unit or leave in place for looks. The new caps will fit underneath. They will not leak and they'll out last us all. 73 Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: Topband resource
>So how is it that I consistently work all over the world on 160m with my >horizontal dipole at 50ft?! Oh boy, here we go again. As I believe I have pointed out before, your QTH is not that far from a fairly vast amount of salt water. You can believe anything you want, but your experience if not embellished, is atypical and does not refute the general guidance that vertical monopoles with good ground systems perform better for relatively long transmission distances on medium wave. So you "consistently work all over the world on 160m." Over what period of time? 40 years? One contest? Have you ever tried some sort of T or inverted L over 60+ radials using your dipole for receiving? Perhaps you'd find you can "work all over the world" in a much shorter time period? Your repeated bragging/questioning about your installation as a thinly veiled argument is disinformation and it is not helpful. The physics of antennas do not get suspended for your location. 73 Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: FT-8 Contest would be great for Topband
>Modes over last 2 hours Some may say this is nit picking but to me it is important: MOST of those so called modes listed are NOT different modes of transmission, they are digital protocols. A mode of transmission is a method for altering a RF carrier so it conveys information. CW is a mode. So is AM. Spark is not a mode; it is an altogether different way of generating RF. FSK is a mode. With most computer generated digital data transmissions, the method is the same; only the digital protocol changes. Therefore, they are not separate discrete modes. Let's not aggrandize computer generated transmission--a lot of digital stuff is one mode, but many different formats or protocols. 73 Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: 160m vertical saltwater grounding
Interesting information here: http://www.arrl.org/files/file/Antenna%20Book%20Supplemental%20Files/22nd%20Edition/Seawater%20Grounds%20-%20by%20N6LF.pdf Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: K9ay loop not performing
Actually, if you have a quarter wave driven element and you are disconnecting it at the feedpoint, your relay concern shouldn't be voltage so much as current. Fast switching and large contact surface is more important than voltage handling. 73 Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: K9ay loop not performing
If you open the tx antenna feedline for rx, from my experience, you need to completely open the entire feedline, namely the coaxial cable shield as well as the center conductor. coaxial relays that maintain conductivity of the shield when N.O. won't detune/isolate the tx antenna. I use a pair of open frame relays for this. Fortunately on 1800 kc the Z bump is almost nonexistent. What will govern your choice of relay is tx power and tx time, and whether or not you require QSK. I do not, but if you do, you may have to consider something like multiple paralleled reed relays tor speed and power, or vacuum relays. 73 Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: spark gap construction ideas for 160m tower
>Curious as why non resistor spark plugs aren't on the list of choices. Easy to >gap. Pt-Pt electrodes last forever (100k miles). There was a ham mounting two >on a Cu plate for ladder line, but that was many years ago. < That can work but the other construction methods offer a wider range of v. breakdown. keep in mind the articles were for broadcast with a variety of feedpoint voltages. But for 160 m., there's nothing wrong with looking to medium wave broadcast for ideas to take away. 73 Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: spark gap construction ideas for 160m tower
There are a number of ways of making a ball gap. but more important is arriving at the correct spacing for the gap. The way rain is handled is usually by positioning the balls one above the other so a water bridge doesn't form between the balls. Read this by Mark Persons: https://www.radioworld.com/tech-and-gear/understanding-arc-gaps-for-am-systems Here's another treatment: https://www.thebdr.net/articles/steel/twrs/LimitingStatic.pdf Kintronic sells them https://www.kintronic.com/shop/tower-ball-gap/ 73 Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: Furnace RFI
Went through this about 2 years ago. Firstly, define "efficient." If you mean over 90%, as in one of those two stage furnaces with PVC handling moisture then you are consigned to having to use a variable speed DC motor (there are no variable speed AC motors, only speed settings you set manually at installation) that will cause RFI because it is run on variable duration square wave DC. You will have to have the HVAC contractor install a manufacturer supplied hush kit, or do it yourself. The hush kits are over priced and many contractors are unfamiliar with them and RFI. Or, you can do what I did and get a single stage 80% efficient furnace that runs on an AC blower and accept 10% less efficiency and get on with life. Mine is around 80K BTU, not extremely big. There are larger ones, or were. I went with American Standard, an Ingersol Rand brand name. There are around three companies that make all the furnaces; IR is one of them. I've heard the AC blower furnaces are going to be history in a few years after which they'll all be high eff. DC because gov't is obsessed with this, but that's another topic. 73 Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: inverted l
If you have a properly constructed typical inverted L, i.e. 50 or 60 foot vertical and similar length horizontal, AND a good ground system serving as the other half of the antenna, your feedpoint Z will be 10 to 20 ohms. The reason you need a matching network is that most coax (this assumes you are feeding the antenna with a coaxial transmission line) has a characteristic impedance of 50 ohms or more. If you found coax with a characteristic Z of 15 ohms you probably wouldn't need a matching network. Let's say you don't bother with a network. Your line will have voltage maxima and current maxima on it and exhibit more loss but it may be okay depending on the line used and its length. The other problem is whether or not your transmitter has an output network that can handle the other than 50 ohms Z it will see at the end of the line with this arrangement. If all of this is a problem for one reason or another, you need a matching network. With antennas that have feedpoints near the ground, you can place it at the feedpoint which is nice. Any inverted L with an adequate ground system, elevated or buried, will have a pretty narrow impedance bandwidth for matching purposes. Anything that exhibits a fairly flat bandwidth, say 50 or more kc, is probably not radiating efficiently. You can improve this, but the way to do it is to widen the width of the driven element, for example instead of using a single wire, employ a cage. You can raise the impedance of the L by increasing the vertical length. Eventually with 1/4 wave length vertical, the ideal Z will be around 36 ohms, but then it ceases to be an inverted L. 73 Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: RFI on TB
>This has got to be on a case-by case basis. I don't have any listening >antennas, so i listen on my transmit vertical. It works fine. For me. Most >of the time. Would I hear more stuff with listening antennas? I bet the >answer is yes under certain conditions. Yes under certain circumstances using the tx antenna is okay for rx, the most obvious example being local communications with a ham a few miles away. But I don't know of any serious 160 m. operator who does not have separate receive antennas. The reason is that the reciprocity that allows the tx antenna to also work on rx starts to break down as we go lower in frequency, beginning on 75 m. but by the time we tune down to medium wave, it is very noticeable and receiving becomes more about signal over noise than pure signal strength. As new hams, we probably all had the experience of mistakenly tuning across 160 with the wrong antenna, maybe a 40 m. dipole, and wow, we hear a lot. We excitedly hooked up our 160 m. antenna only to hear nothing, or a lot less. What went wrong? Ah, the education begins. The other problem with the same tx/rx antenna for anyone except the few lucky ones with no noise sources, is transmitting on top of a QSO without realizing it. 73 Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: RFI on TB
> Over past few months, I have picked up an S5-S7 noise signature on my TB inv > L antenna with K2AV FCP system. I would not use an inverted L for receiving. Unusable for rx at my QTH but FB for transmitting. 73 Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Topband: FT-8 My Recent Experience
> I can't get into any computer mode, mainly because I've been a software >engineer for almost 40 year and dealing with computers at home is a >non-starter with me.I like ARC-5s, BC-348s, and Navy RBB's >myself.. Same here. Computer science major; 30 years in front of monitors and keyboards all day; database management, writing codeand I know hams who spend days and days fiddling with PCs and logging softwareWhy? What a waste of valuable radio time in my opinion. Not only do I reject computer "modes," but I run a computer free shack. Great FT8 story by the way. 73 Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Topband: Voltage at top of vertical and scaling?
I'd also put RF chokes in series with the DC relay lines, at the base of the vertical antenna to further keep RF off it but also to break it up so the relay line doesn't detune the 80 m. vertical, perhaps with another pair at the shack entrance. All this sure seems like a lot of work which is why I simply hung a wire for 160 inverted L from a 3 foot standoff at the top of my 80 m. mast and did my dual band that way, using the same ground system for both. 73 Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: Lack of Activity
There's activity and then there's "activity." I take it that "activity" in this discussion really means DX. It so happens that there's other kinds of operating going on on 160 m. besides DX chasing if you can tolerate the tedium and torture of an enjoyable ragchew with an ordinary ham nearby. As for DX, I imagine that all hams are going SK at the same rate everywhere, meaning that an entity with a ham population of 50 in 1980, now has a ham population of 5, with maybe one active on 160. 73 Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: Inverted L improvement question
> It doesn't work very well. Last night it was much poorer on receive and > transmit than my existing 43' vertical setup. I'm not sure what to think. Your fundamental problem is a lack of understanding of how a monopole works, specifically a base fed vertical with a ground system. Anyone who tries to use a ground system that converges on a point removed 10 or 20 feet from where the vertical element is excited does not really understand how these antennas work. You can't expect good performance by distorting the geometry of the antenna to bring the feed point to the counter poise convergence point. You can't just throw out physics. it will radiate something, it just won't meet your expectations, as you mentioned. If I were you, I'd fall back and start doing some reading.These antennas in their various forms have been developed since the 1930s. There's a pretty vast amount of information about them, but what you will probably benefit most from, is a college text book treatment, the kind of text used for a class on radio broadcast engineering. One such text is Radio-Electronic Transmission Fundamentals by B. Whitfield Griffith, Jr. 2nd ed. It has a few chapters on medium wave verticals, ground systems, radiation resistance, current and field intensity but is written for students in an easy to understand way. Perhaps you can find a used copy on-line. It's better to take your time and study these things, then use your knowledge to correctly construct the antenna, even it it means waiting until next fall to try it. 73 Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: Inverted L improvement question - Part 2
Hmmmyou DID relocate or rebuild your ground system so it converges on a point below the bottom of the 100 foot tall wire right? I mean, you aren't using the 43 foot vert. ground system with the 100' wire? A series fed vertical isn't rocket science so let's not over think this. If it doesn't work well it is probably inefficient. I'd make sure your ground system is adequate. No, you can't use an existing ground system that converges on a point 30 or 40 feet away from the 100' wire. Yes, I've had people ask me if they can do that, so it is worth mentioning. You can go the elevated route, but it is _critical_ that it be constructed correctly to adequately replace a full ground system at or below grade. You need four radials parallel to earth extending out 90 degrees from each other and their lengths must be equal and 90 degrees long (1/4 w.) at frequency. The ends must be h.v. insulated. They should be elevated 20 feet on 160 m. to completely de-couple from earth. 73 Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Topband: RF in the DX Eng. NCC-1 (and a fix)
Merry Christmas and Happy New Year: On 160 m. (probably due to the close proximity to my inverted L) my NCC-1 rx antenna phasing box would snap crackle and pop on transmit, most likely the result of RF getting into the nine relay coils inside. If you employ phased rx antennas and a tx antenna, all in a small space, running over 1 KW you may have noticed this also. The stock box has some small bypass caps on the DC supply line in, and the T/R control line in, but they were not enough to keep RF out entirely. The fix for me was a small 100 micro-Henry choke inside the box in series with the floating center of the T/R line, along with a 0.015 mfd cap on the cold side of the choke to ground, and a pair of the same chokes in series with the DC +,- supply line into the box at its entrance. The DC supply jack has an adequate amount of stock bypass capacitance so I didn't add any more. 0.1 mfd if I remember correctly. These fixes quieted the NCC-1 down for me and were a lot easier than trying to bypass each relay coil to ground with capacitors. 73 Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: Inverted L improvement question
If your inverted L is any good at all it will suck as a receiving antenna. This is one of the key things to accept about medium wave but many casual 160 m. operators can't wrap their heads around it. A flame throwing tx antenna will probably have a completely unacceptable noise level on receive. Tx/rx reciprocity works on HF but not as well on medum wave. Separate rx antenna(s) are mandatory.A significant irritant on 160 are the operators with poor antennas that hear great, therefore they expect to be heard equally well, and can't be made to believe they are piss weak when they transmit. I'll pass along one idea I got from a friend of mine regarding your tree holding inverted L. Since the tree is probably a substantial support, I'd lower the L (this is assuming you have a pulley on a rope over the branch, through the pulley another rope attached to an insulator through which the top of the inverted L transfers from vertical to horizontal, all to facilitate raising and lowering) and bolt three more copper wires to the current wire, near the point at the insulator, with one wire continuing on through the insulator. The 3 new wires should be long enough to drape down to the ground. Now pull it back up and spread your four wires so that near ground, each one is in the corner of a square with 6 to 12 feet on a side, each wire attached to an insulator which in turn is attached to a rope that proceeds on to an anchor stake of some sort. Next, run a ring of wire around the square you have made so all four vertical wires are bonded to each other, the square wire being around two feet off the ground. Bring in your feedline and connect it, or your matching network if you have one out there, to the ground system and the square ring wire. I'd use awg 14 7 strand hard drawn bare copper wire for all of this. What you will have done is a wire simulation of a free standing tower insulated from ground with a 6 to 12 foot face around 100 feet tall. You should have a very flat impedance curve with this which will greatly simplify covering the band with minimal matching network adjustment, and at much less cost than what a 100 foot 12 foot wide skirt fed tower would cost. If I had a tree like what you must have, this would take me all of two seconds to decide to do. Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: Rather use N-type (was Re: The answer to PL-259
Some of you fellows who want to use Ns may benefit from this hint and kink: https://www.radioworld.com/columns-and-views/repair-and-protect-type-n-connectors Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: Rather use N-type (was Re: The answer to PL-259
>>W6NL asked me this question - would you run 1500 watts with BNC connectors? It depends on the duty cycle, length of transmission and vswr. Brief contester type transmissons at 50% d/c into a load with Z = line characteristic Z is probably okay. AM broadcasting 1 KW carrier for 24 hours probably not. What's the way to Carnegie Hall? Practice, practice, practice. What's the way to solder a UHF male? See above. It's similar to baking a cake. Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: Impedance of inv l?
My inv. L is 50 feet up and 70 horizontal. Wire is #14 bare 7 strand hard drawn. 3 feet out from mast. 101 radials, two ground rods and aluminum siding on garage strapped in to ground sys. on around 1840 Z is 11 R and ~ 20 ohms X. A typical inverted L with a good ground system should be down around 15 ohms at feedpoint from my experience and rapidly change above and below the minimum reactance point. High resistance flat antennas have an inadequate ground system. Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: 160m Condx
>Why is it ever necessary to call on 1830, 1820, 1822 etc. exactly? Call CQ on >1820.3, or 1820.4 or 1822.6 or 1827.8. This only started with plastic radios and digital displays and got worse with dial resolution down to one cycle. Back when everyone had VFOs like the HA-5 with dial markers only every 50 kc no one ever thought about it. All that mattered was being inside the band and zero beat to the fellow being worked. Now for some reason hams act like the bands are channelized every 5 kc. Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: RG6 connectors and installation
Don't re-invent the wheel. There are cable installers all over the place--these are people who are given the tools and connectors by Comcast and other big companies to make high reliability installations. When you see a cable truck out on location stop and ask the guy what he uses. If you explain why you are interested, you will probably get all the information you need to order the F males and tools yourself, but also find out what they use for cable. It's usually Belden "drop cable" high quality outdoor RG6. My experience has been these materials and tools are superior to what the ham radio vendors sell. 73 Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: Radial wire
>Rob, Not barbed wire, but electric fence wire. This wire stays good for >decades. Look at the horse and cattle farms around you. It has the same >conductivity as your galvanized steel tower. Nor does anyone consider >making a tower out of copper or copper clad steel.☺ A radial system of 60 >1/4 wave of #10 copper cost 50 times what the electric fence wire costs. Big difference between wire on fence and buried. I've mistakenly installed galvanized steel ground rods here. Pulling them back out 10 years later they were nothing but rust and useless. The surface area of a tower's galvanized legs is much greater than the surface area of a skinny wire, therefore the RF conductivity is NOT the same. copper has in fact become expensive compared to 15 years ago but all antennas have gotten expensive. The ground system is 1/2 of an antenna. But, unlike the directly excited part, you don't have to do the ground system all at once. You can put it in at affordable segments over time, assuming you will use it for years to come. 73 Rob K5UJ _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Radial wire
Oh man, any time this topic comes up anywhere the guys come out with all kinds of suggestions for wire that won't last like galvanized steel and electric fence wire. Nix nix nix...if you want a permanent ground system go with copper, insulated or not. Stranded doesn't lie down as well; you want soft drawn copper sold. Stranded wants to spring up and stay coiled, especially if it is hard drawn antenna wire. Use that for antennas. Copper clad steel can be hard to work with too unless you have a spool on a radial plow and are laying it into a slit a few inches deep with a tractor. But if the installation only has to last a few months then use the barb wire, etc. 73 Rob K5UJ _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: OT - US Hams, WWV closure
>Some folks have commented on WWV's >minuscule operating expense when compared to the total federal budget, but >the problem with that thinking is we have thousands of federal programs and >departmental budgets that also contribute just a tiny fraction to federal >expense. Collectively, it adds up to a much larger figure. No matter what >goes away, the impact is felt by someone. I've heard Fed. Gov't burns through $6 Mil. every minute (maybe it's every second). In the time it took to read this far, Bam another $6 million. Sure there are lots of dinky things the U.S. blows money on and if no one defends them then they go away if they're up for a defund. NIST is sending up a trial balloon maybe? Well, if there are enough tech. trogs using WWV and we make enough noise, maybe this dinky little program will get saved. Let them cut funding for some stupid study on why moss only grows in shade. Bam, there went another $6 million. Don't know about all of you but I have a hell of a lot of things to do besides mess around trying to set up my own rubidium doohicky because WWV went away. Bam there went another $6 million. 73 Rob K5UJ _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: NEW CALL for WA8WZG
>Finally I get an email from the FCC this morning , I won a lottery!! FB on the new call, but is this all you get? Don't they mail out something on paper? Rob K5UJ _ Topband Reflector Archives - http://www.contesting.com/_topband
Topband: Baker Island DXpedition on 160
I respectfully suggest the Baker Is. dxpedition be postponed for a few years until band condx improve. It makes no sense to me to mount this costly undertaking to a limited access location when propagation is in the toilet. If USFWS is managing access, they've lately shown that they'll only approve trips to islands under their custodianship every 10 years or so. If this is the case with Baker Is., then this trip will make another one in a few years impossible. Another point I'd like to make is that a later trip might afford a chance to renegotiate what I consider a ridiculous antenna limit, which seems to be based on a ridiculous antenna design, namely the "43 foot all-band vertical."Such a height with top loading might work okay on 80 meters but on 160 its efficiency will be poor. 73 Rob K5UJ _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Adding chicken wire or mesh on top of radial field
for permanent installation it's a waste of time because thin wire steel mesh (chicken fence mesh) will rust away in most ground in a short time. Recommend copper mesh but professionally it only seems to be employed around the base pier of voltage fed towers. For a current fed tower a lot of radials near the feed point, >= 90, is good enough. 73 Rob K5UJ _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Soil conductivity maps
Suggest that for Hawaii or other locations where you want specific soil data, contact local small AM or walk in and ask to talk to C.E. Big corp. owned stations will give corporate hq. run around. >>#1 As far south in the country as possible due to better propagation. bzzt, sorry but South = high thunderstorm QRN. nix nix. QRN is everywhere but in South you get shut down due to noise level or proximity to lightning. 73 Rob K5UJ _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: low inv-vee
1. You never use an inverted L or other vertical for receiving, unless maybe, you are in a QTH so remote and noise free it might work. But in-town, forget it. 2, From my experience, 7 or 8 out of 10 hams on 160 m., have poor antennas, usually low horizontal wires. Most of these fellows are casual operators who ragchew and are okay as long as they understand the limits of their antennas. Rob K5UJ _ Topband Reflector Archives - http://www.contesting.com/_topband
Topband: decoupling Inv L for loop on Rx
I found I had to put a relay in the feedline to my inverted L to completely open the line on rx. Your typical "coax relay" only opens the center conductor. Fortunately on 160 m. an open frame relay that opens the entire line isn't much of an impedance bump. It is essential that the relay be between the antenna and the shack ground system, matching network etc. The inverted L must be isolated from the shack and rx loop antenna system on receive. 73 Rob K5UJ _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: 1/2 wave inv L
A 180 or 190 degree vertical radiator presents a few different problems compared to one 90 degrees long, due to the high voltage at the feedpoint. You can have ground loss there, but since it is more of a coupling problem than a return current problem, the earth shield is usually a copper mesh that extends out around the pier about 20 feet. Think in terms of the loss at the ends of an inverted V when the ends are anchored near the ground. Since the feedpoint is high voltage, the way in which the base of the radiator is insulated becomes more important, and the ball gap must be adjusted accordingly, and access to the area kept more secure to prevent casual contact with the excited base of the radiator. If a concrete pier is used to hold a ceramic base insulator, the pier must be bypassed with copper ground strap so it is not part of the voltage gradient between the mesh and the radiator, as concrete is conductive. For ham (in my opinion) none of this is worth the trouble, and I'd go with a quarter wave antenna. 73 Rob K5UJ _ Topband Reflector Archives - http://www.contesting.com/_topband
Topband: Radial Wire System Comparison - (was adding a parasitic reflect
>> I have researched Laport's material, and find nothing that compares multi-tower array performance when using insulated radial wire versus uninsulated wire when using a bus wire at the radial overlap points. Since his worked in the 1950s mostly focused on directional broadcast tower arrays -- and the use of heavy-gauge wire, possibly insulated radial wire wasn't considered because of long-term insulation decomposition that one day >> results in electrical contact between overlapping radials. I doubt if you'll find anything in the broadcast literature. The reason is that the standard DA ground system as far as I know, has always involved strapping radials to a copper strap running along the line of radial intersection, clipping off the radial wire that runs past the strap. And the standard ground system wire is AWG solid bare soft drawn. I think engineering firms like everything done the same way from one site to the next to reduce variables for a full proof and get a DA dialed in to the licensed pattern. Why the teflon insulation? 73 Rob K5UJ _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: FT-8 question
> As is, its infuriating listening to high noise > levels on 160m. If I cant hear on 160m...except for the usual louder > stations, Im not going to even try TX. Don't let noise stop you from transmitting. >Right now, Im trying to evaluate if 160m is even worth >the effort required. Are the rest of you on 5 acres out in the woods ? Nope, I am on a 50 x 100 foot lot in town. Try getting a pair of small rx loops, two rotators, and a phasing network. I have two pesky noise sources from two directions and I can put one in the nulls of the loops and phase out the other. Of course all of this is a lot more trouble than just putting up a dipole so 160 isn't for everyone, but the challenge sort of gets into you. I refuse to submit to the plasma TV authority and let 160 m. be the province of those with "vast tracts of land." You don't have to have a S0 noise level to have a nice QSO with someone. 73 Rob K5UJ _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: FT8 discussion
Actually the problem with the alleged QRM and FT8 is more about simply identifying ham computerized modes of digital transmission and reception and separating them out from the rest of the noise generated by poorly filtered appliances, leaky cable TV, power line data communications etc. I am evidently a troglodyte who does not have a computer in the shack and I refuse to run one for no reason other than to be able to demodulate and identify ham digital signals. I believe the onus is on the digital mode operator to make his emissions identifiable as ham radio to others, who like me, may be operating analog equipment capable of demodulating common basic transmission modes such as analog phone, and CW keyed with radiotelegraph code. What I'm getting at is that a big mistake was made in the 1980s with the CW ID requirement for RTTY and SSTV was dropped to convenience those operators. It was burdensome then, but SSTV and Baudot RTTY was pretty easy to ID (although you couldn't tell a ham station from an intruder). Now, with seemingly zillion digital computer modes, it's impossible for someone like me to tell a licensed ham from an intruder, or a variable speed furnace motor.Ironically, an automatic fast CW ID at the end of each transmission would be easy to encode in a computer and implement, and it would not be disruptive since the transmission is ending anyway. It's time for FCC to reinstate the CW ID requirement. Until then, my default is to assume any emission I cannot identify, to be either an intruder, or noise from an appliance and carry on accordingly. 73 Rob K5UJ _ Topband Reflector Archives - http://www.contesting.com/_topband
Topband: Fwd: Fw: Solar Storm September 6th in real time Video - K5UJ de DK7PE
Posting for Rudi R.A. -- Forwarded message -- From: Rudolf Klos Date: Fri, Oct 6, 2017 at 2:58 PM Subject: Fw: Solar Storm September 6th in real time Video - K5UJ de DK7PE To: ranchoro...@gmail.com Hi Rob, I tried to post this infor regarding the latest strongest solar storm since 12 years. Unfortunately I can not post it as my email is not known. Could you please load it up into the Topband site. Thanks 73s Rudi DK7PE Hi all, September 6th 2017 we had the biggest solar storm since 10 to 15 years (ref. NASA). During that time I was in Northern Norway on a photo excursion. When the particles arrived on earth, on Sep 8th, I was able to make a short video what shows some of the extreme Northern Lights in real time. What caused the Bands to collaps looked like this: YOUTUBE: https://youtu.be/mdcwEGra1Ts To me it woul'd be interesting to know what happened on 160m in advance between Sep. 6th to 8th. In the past I observed great DX openings on Top Band just before the bands completely broke down. Any observations? 73s Rudi DK7PE _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: RX/TX Antenna decoupling, (OFF LIST)
> Thanks for sharing this info. > Would you please provide more information on the relay model number and how > it is wired into your system. I used a P&B open frame relay 4PDT but a single throw will work. What's important is that the relay use metal other than steel (or other magnetic metal) for the RF path. The P&B PM17DY satisfies this requirement. I mounted it in a plastic box and mounted UHF jacks on the ends and ran copper strap and AWG10 stranded to the relay, using the AWG10 for the center conductor. I used two poles for the center and two for the cable shield. On rx the relay is open and the inverted L is disconnected from the shack and common mode RF prevented from continuing to the shack. The plastic box is important for this -- a typical metal box would allow the shield RF to continue from the UHF jack flanges around the relay at all times. The relay I used has a 24 v. coil because my T/R sequencing system runs on a 24 v. DC supply. This as all antenna relays should be used with a sequencer to avoid hot switching. Obviously this is not a solution if one desires QSK. In that case a faster switch is needed. 73 Rob K5UJ _ Topband Reflector Archives - http://www.contesting.com/_topband