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Re: Some thoughts on cases for exterior loop antenna amplifiers
Michael,
Maybe a mm or less. I guess he just uses the smallest drill bit available. I will try to measure it :) Regards, Simon On Sun, Aug 18, 2024 at 2:48?PM Michael.2E0IHW via groups.io <blumu@...> wrote:
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Re: Some thoughts on cases for exterior loop antenna amplifiers
Simon, very useful info.
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What size is your "tiny hole" ? Michael 2E0IHW - near the Atlantic... ...box venting: I've got CCW Experimenter's amp in February this year and it only has a tiny hole at the bottom of the box. |
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Re: Some thoughts on cases for exterior loop antenna amplifiers
wn4isx
Well a tiny hole is certainly the least expensive and if he's switched from Hylec vents to tiny holes, perhaps I need to rethink my options. I will say the CCW dual polarity H/V active antenna with the Hylec hasn't had any condensation.
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After surgery I'll have time where I'm limited in my motion and I hope to do some serious research on how the big boys protect their IP cases. |
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Re: Good Morning from Rural VA
Hi Guy,
Of that would be of any help here is a list of parts I used: PVC IP67 box: (different sizes available) Cable glands: (PG25 is a bit wide for CAT cable that goes down to receiver, so either some silicon self-adhesing tape can be used or PG19 just for the cable entry) Clamps that I used on the back of the box: (U-Bolts were replaced with straight 5/16 bolts) Straight bolts: (not really sure if they are high quality SS, but I didn't care much for this application) I also used 5/16" wide fender washers from the inside to hold the bolt's heads. Plus a good amount of heat glue (good silicone should probably be better). Mast: (not as strong as other expensive ones, but we will see how it will hold up and I only used 3 lower sections. Sections glued together with epoxy to prevent collapsing down.) CAT8 SFTP "heavy duty" outdoor rated 25ft patch cable used to connect antenna to LZ1AQ control board: . I put quite a bit of FT240 toroid's on it to fight the noise and interference at my Urban location (2 at antenna, 3 at control board and 1 in the middle of the cable). Tripods I'm using at the moment: 7/8" copper pipe that I used with another loop and decided not to use with this one due to it's weight: 5/8" aluminum tubing (not from these sellers but very similar item): !94040!US!-1&itmprp=enc%3AAQAJAAAA8HoV3kP08IDx%2BKZ9MfhVJKnbBHv4DsF7CvTgz%2Fz2seoNNj1Z0J7XLn4m6xDiZ%2FZvf95r9lIDbMA14Yc5PbKP1vRNd47P6lfVeox4SSjm8G2Rspck0p1YQwOasqBofv00QB%2BWrOCyLvHBGinLqBZz2ZTTi4e4y4KaMduJmBrs8Y79uBvdc9YZ7F6Z69vPOILYYPQYkI8jSc8EoFvegz5NwI0MHC1KnloljYZ5XT%2BjDdBMVwaF7jSQNSihbzZrpkz9JFpKmgck3tOoUWNuvTktZ%2BET%2F6WLzvXAVThswPcc36l6sBKmiHJpBEkwyfEiyMyeZQ%3D%3D%7Ctkp%3ABFBM5K7q86xk Both 7/8" OD copper thin wall tubing and 5/8" OD aluminum tubing are thin walled and can be formed by hand - no roller is needed, just time to make it more or less round shape. But as I mentioned before if I need to redo it I'd probably use 1" OD PEC-AL-PEC instead. Pic of the antenna from the back: Best Regards, Simon KM6MUL On Fri, Aug 16, 2024 at 4:25?AM Guy Mengel N1GMM via groups.io <guy@...> wrote:
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Marconi XG189 Goniometer
I wonder if anyone here has had any experience of the XG189?
I recently bought one and it seems to work in a lashed up table top experiment using a sig gen and a dual channel scope..
I am particularly interested in any RF antenna experiments and findings from members here.
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Pete Worrall
G4GJL |
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Re: Some thoughts on cases for exterior loop antenna amplifiers
wn4isx
The only sintered filters I ever saw were the ones on the small compressors that drove the air bearing heads on an Ampex Quad machine.
The heads scanned across a 2" tape at 14.386RPM.
There was a ~1" inlet filter of sintered brass or bronze, followed by a 5" sub micron filter with a final filter right before the feed to the air bearing.
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You've never lived until a quad head decides to come apart. The heads come off at the speed of bullets.
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Or, sometimes a head would start to clog, so you'd use a 4" square texwipe soaked in Xylene, folded to form a ridge and try to gently unclog the head. And, 1 time out of ~20 a head would grab the cloth and pull it into the gate.
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Yea a lot of fun.? Heads cost ~$3000 in 1980. Management accepted the occasional destruction of a quad head and tape as the cost of doing business.
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You spliced quad tape by spraying super fine iron particles in a Freon carrier and cutting between the scan lines across the tape. I so don't miss that I'm tempted to celebrate.
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My personal failure mode was when an air bearing died. It sounded like a banshee being tortured and almost always ended with the head assembly experiencing a "rapid unscheduled disassembly." Everyone ducked for shelter. We had painted lines on the floor for each machine showing the most probable path of debris flow. I generally fell the floor and rolled up against the machine about to go. I was below any possible debris.
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Again, I so do not miss quad VTRs I am tempted to take my wife out today for steak dinner to celebrate their demise.?
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OMG there is an Groups IO page devoted to Quad machines!
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I am so not joining!!!!! I still have nightmares about rush feeds and needing a quad machine ready RFN, and trying to tweak all the adjustments on the air as the beast warmed up. My first stint as solo engineer was the result of the chief engineering collapsing from food poisoning after an hour of training. I realized about 10 seconds before air time he'd given me the wrong tape. It had taken me 2 hours to set the VTR up and there wasn't a thing I could do except watch the trainwreck.
In the aftermath the chief almost got fired. He was honest and told them he'd given me the wrong tape and there wasn't anything I could have done in the time left.
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A week later I'd have told master control to run a PSA or 2, different tape source, 3/4" U-Matic, while I swapped tapes and did a hot set up on the air.
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We were the master media source and control point for ACSN which morphed into a commercial operation, TLC.?We fed a number of C band downlinks scattered throughout Appalachia.
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https://en.wikipedia.org/wiki/TLC_(TV_network)
This says 15 sites but there were at least 21.
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Re: Some thoughts on cases for exterior loop antenna amplifiers
On 8/17/2024 13:37, wn4isx wrote:
I'd be a bit concerned over the size of the "holes" in the sintered brass, they might be large enough to allow water ingress.I've seen some that also have a filter material within them, some multiple layers, screen, sintered material, a fibrous material, what looks like blotter paper, I think some are designed for oil, or water, it all depends on the application. Of course, pointing downward helps, I have a case with eight vents, in the bottom, no water issues. A generic search of images for "breather vent", should show different styles. Kurt |
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Re: Some thoughts on cases for exterior loop antenna amplifiers
wn4isx
On Sat, Aug 17, 2024 at 04:37 PM, wn4isx wrote:
This was in June 2023 and they finally cut the dish mounts off at ground level 3 or 4 years ago.Ah the joys of dyslexia and fatigue, I mean 2003. ?
I had to write the final notes in our FCC log, "Satellite dish moved to lowest elevation, power has been removed and the system should be considered decommissioned, TAF, 2003.10.29 10:00AM." then my signature and I sent the log to the archivist. I'd also opened the master breakers, individual breakers, pulled the control software so it would have been somewhat difficult for the system to be operated.?
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After Captain Midnight, the FCC frowns on unattended satellite uplinks.
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Re: Some thoughts on cases for exterior loop antenna amplifiers
wn4isx
I'd be a bit concerned over the size of the "holes" in the sintered brass, they might be large enough to allow water ingress.?
I've spent the day searching for how the big boys protect their exterior IP case/delicate electronics.
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I know our 10M satellite up/down link dish used waveguide, aluminum with gold plated insides. The flanges were double "O" ring gasketed but the system still leaked.?
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We had a dry air pump system that produced 0.01PSI. The operations manual had dire warnings about how moisture would cause the gold to "delaminate" which would require replacing all the waveguide.
It was with some sadness the day I shut down the entire system because I knew the $250K system would quickly turn into scrap because moisture would not only ruin the waveguide but also the travelling wave power amp.
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This was in June 2023 and they finally cut the dish mounts off at ground level 3 or 4 years ago.
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Water where it doesn't belong can cause serious problems, so the big boys must have a good idea how to vent their IP6 cases, but darned if I can find any useful references, which is extremely frustrating because I am generally very good at research.
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Perhaps this area is part of the dark arcane bag of tightly held trade secrets.
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Re: Some thoughts on cases for exterior loop antenna amplifiers
On 8/17/2024 04:43, Fred M wrote:
Whith a simple hole, sometimes small insects get in and the IP-class of sealed cases is lost. Thus instead of a simple hole, i prefer protective air and moisture vents. There are two versions, cheaper adhesive vents and more expensive screw in / plug in vents.I've seen the stick on, now I know what those are! In recent projects, I've been using brass, or stainless steel "breather" vents. Here is an example: Kurt |
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Re: Schematic & PCB design software
Hi Henry,
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Unfortunately, I suspect Altium may fall into that category at some point, it's just too tempting a prospect to avoid acquisition by a competitor. Autodesk being one I can immediately think of.
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If you are already using it, then stick, but otherwise the only Opensource, free, future proof and widely adopted (as much as any can be) in my mind is KiCad.
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I definitely agree that I certainly wouldn't bother learning any of the simple offerings, or those produced by small "one man band" type companies. If you are going to learn the basics, then you may as well invest a bit more time in something that will not quickly outgrow. I have wasted far too much effort in the past, wanting to quickly produce something, and then getting caught out later when the design had progressed, but the required tool was not available in the free / trial / basic version.
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This is also how the larger companies try to suck folks in to their ecosystems, by initially providing free "student" licences to trainees and graduates.
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Regards,
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Martin
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On Sat, Aug 17, 2024 at 12:24 PM, <tardivat@...> wrote:
As Martin has indicated many of these CAD tools come and go and you invest time and become good at it then? either the company folds, is sold off and destroyed by the new company or it just becomes naturally obsolete from lack of further updates. For these reasons? I am reluctant to waste time? learning any time in any new CAD tool if its not widely used in industry. |
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Re: Some thoughts on cases for exterior loop antenna amplifiers
wn4isx
? My CCW dual polarity H/V antenna, has never had condensation. ? Chris used a Hammond RP1060 with a Hylec vent and wire glands of unknown manufacture. There is no obvious name on the exterior. [I'm looking at it right now, not quite willing to tear it apart until my new Hammond cases arrive.] ? The RP1060 has a tongue and grove case with a neoprene gasket. ? The Hylec vent has a special membrane, Polyether sulphone PES, similar to Gortex in that it allows air to freely pass but blocks water. I suspect it has much smaller holes in the material and is even better at blocking water then Gortex. ? I received this antenna at least 3 years ago, maybe 4 or 5 and it was placed in service that weekend and endured a series of storms. ? I opened it after the storms passed, no trace of water, I then installed it "permanently. [I used "" because it's been moved 3 times] ? I opened the case after the first winter, in late March and there was no trace of water. ? Central Kentucky gets a lot more rain in winter then snow.?Here is a list of average monthly temperatures and precipitation https://www.usclimatedata.com/climate/lexington/kentucky/united-states/usky1079 ? As you can see, we receive ~45 inches of precipitation, most of that is in the form of rain. ? I neglected to open the unit for the next few years. I opened it prior to moving last year, August, and then again this spring, March. ? There has never been a trace of condensation. ? As I explained in the post that started this thread, my theory on moisture ingress suggests water doesn't seep in along well sealed seams but is sucked in as air laden with water vapor as the temperature drops and the volume of air inside the case decreases, the water vapor condenses and is trapped. ? [I'll admit I haven't used Charles' and Boyle's Law since university physics...so please bear with me,] ? https://chem.libretexts.org/Courses/University_of_California_Davis/UCD_Chem_002A/UCD_Chem_2A/Text/Unit_III%3A_Physical_Properties_of_Gases/06.03_Relationships_among_Pressure_Temperature_Volume_and_Amount#:~:text=Because%20PV%20is%20a%20constant,equation%20V%20%3D%20constant%2FP. ? V¡ØT [anyone up to calulus?] ? https://www.omnicalculator.com/physics/charles-law "In the second problem, we heat an easily-stretched container. It's filled with nitrogen, which is a good approximation of an ideal gas. We can find that its initial volume is?0.03 ft??at room temperature,?295 K. Then we put it close to the heating source and leave it for a while. After a few minutes, its volume has increased to?0.062 ft?. With all of this data, can we estimate the temperature of our heater?" -------------------------------- Let's reverse this, if the temperature is decreased, the volume of air will decrease from 0.062 ft? to 0.03ft?. [Air is mostly nitrogen and I don't feel like trying to calculate precise thermal expansion/contraction versus temperature for the mixture of gasses that compress out atmosphere.] ? Here is a practical example. Take an empty 2 liter sodapop bottle at room temperature.?Screw the top on tightly. Place in your refrigerator. ? Leave for an hour and then remove, notice how the sides have pulled in? The volume of air in the container has decreased as the result of cooling. ? In the world of electronic enclosures in the real world, do you think the decrease in air volume might not suck in air laden with moisture? And might not an alternative air vent that allows air and water vapor to move both ways might prevent air laden with moisture from condensing because it can escape just like if there were vent holes? ? I am not trying to argue, I will state as a fact the CCW dual polarity antenna with the Hammond case, wire glands, and Hylec vent doesn't have any water condensation after a typical year in central Kentucky. Or after several years in Central Kentucky. ? Also, a Carlon PVC case with a tongue and grove mating surface and the factory supplied flexible gasket (I believe it is neoprene, but I'm not sure), a wire gland and a quarter inch hole with Gortex repair tape on both sides has also never had condensation after a typical central Kentucky winter. This case protects a PA0RDT Mini-Whip antenna. ? I've been playing with active antennas since July 1979. Most were E-Field antennas. All of them experienced "water ingress" [Well except for the vacuum tube unit, it was warm to the touch at 10F and over heated in 50F weather] until the CCW. ? Based on my experience with that antenna I decided to try the Gortex tape for a friend who needed an antenna "now." It was late September, a series of t-storms was forecast the next day and I had a contract job which promised to be a nightmare for the next few months. The Hytec vent has a delay (really long delay) getting here from England, so I took a gamble with the Gortex repair tape. I was out of my preferred spray on conformal silicon coating, so the PCB went in 'naked.' I threw the whole thing together in few hours and half expected it to maybe last the winter but would probably need the PCB replaced come spring. That was 3 years ago. ? https://www.hylec-apl.com/datasheet/1047/JDAE12PA_SW-Datasheet.pdf ? Until proven otherwise, I'm sticking with my "lower air temperature means less air pressure, means sucking in air/moisture from the outside and trapping the moisture inside after it condenses." ? Now I'll agree if you do not properly seal any ports, you will have water "wick" in by capillary action. https://en.wikipedia.org/wiki/Capillary_action ? Look up Capillary action on youtube. There were too many demonstrations for me to pick out the best one. Water will be "sucked in" narrow gaps, the narrower, the further the water will be 'sucked in' regardless of temperature. ? This is capillary action and demonstrates how any unsealed opening can allow water in regardless of air temperature, pressure differential, etc. ? One must properly seal all ports. I use wire glands with "O" rings on the base of the wire gland that mates with the case. ? I've used conformal silicon coating to protect, seal, the seams on PVC cases that don't have tongue and grove / flexible gaskets with the 1/4 hole with Gortex repair tape. ? I have a Geiger counter mounted in aluminum Budd case. [I only want to detect Gamma rays <cosmic rays for a random number project for a cousin of my wife>]. Given the unit operates with 400V, any water condensation would be "a really bad thing." The unit has a ~9V to 400V inverter, is powered via the coax, the clicks are amplified and fed back down the same coax with a Bias-T. ? The coax enters via a wire gland with "O" ring, and I sealed the seams with spray silicon conformal coating. The breathing vent is a Hylec vent. ? This unit has been in constant 7/365 operation for 15 months with no problems. Unless I open the unit, I can't be certain there hasn't been any water ingress, but, given the inverter board is mounted on two strips of double sided tape [non conductive PVC] on the bottom of the case, I have every reason to believe there has been no water ingress. And any condensation on the GM tube would stop detection. ? I accept holes in the bottom were the only way to control condensation in the past, I also accept that modern vents allow us to have better moisture control and keep insects out. ? Our hobby is fun but industry depends on reliable equipment, condensation would be a major problem for them. Somehow I can't see a major telecom outfit relying on a couple of holes to control condensation. ? I suspect Don Clement's use of Qingrong "Blue Breather Plug M12x1.5-10 Venting Screw In Vents for Solar GPS Tracker Box, Outdoor Lighting Prevent Condensation,5G Outdoor Telecom Enclosure" will work every bit as good as the more expensive (and damn near unobtainable) Hylec or Honeywell. ? The secret is in the membrane that allows air to pass but stops water. I suspect Honeywell and Qingrong [and many others] have developed/copied the membrane used by Hylec. ? Given the 'really bad stuff happening if there is water condensation in a high voltage PV array / control' I suspect Qingrong's products almost certainly work as advertised. ? I've ordered several and I'll see how they work. I'm still going to stick to the Hylec for critical applications until I get a better feel for the Honeywell and Qingrong. ? The stick on water barriers mentioned by Fred M. appear to be a bit more professional then my Gortex tape. ? ? ? |
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Re: Schematic & PCB design software
On Sat, Aug 17, 2024 at 05:24 AM, <tardivat@...> wrote:
Just remember if you want to be a pro in PCB design stick and learn imperial if you are a metric country.? Thats design rule 1!A modern PCB design Software can handle metric als well as medieval imperial measures in parallel. :-) The challenge is more with the user, not for the Software. Footprints and pitch of most throug-hole and integrated circuits are by default in fractions of an inch. The rest is up to you.
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with regards from the metric world
Fred |
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Re: Schematic & PCB design software
If Sprint is too simplistic then in my view? use Altium? if you want to invest in a future proof solution. Even if you can find a old version of Protel 98SE? it can do just about everything and all the PCB houses support protel PCB files. Its not hard to find for free!
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As Martin has indicated many of these CAD tools come and go and you invest time and become good at it then? either the company folds, is sold off and destroyed by the new company or it just becomes naturally obsolete from lack of further updates. For these reasons? I am reluctant to waste time? learning any time in any new CAD tool if its not widely used in industry.
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Then just look at the Libraries and footprint files in PCB design software. You would have thought that there would be some kind of global standard for PVB libraries by now. Everyone has their own standards. You can invest in a considerable amount of time building RF connectors and specialised connector parts for your library. Once you are familiar with 1 or 2 PCB? CAD programs I feel that switching from one to the other to do a PCB layout becomes pretty straightforward. What breaks many PCB CAD programs is the lack of library parts which can slow you down considerably especially common RF parts and connectors which can have pretty precise footprints.
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Just remember if you want to be a pro in PCB design stick and learn imperial if you are a metric country.? Thats design rule 1!
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Henry |
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Re: Some thoughts on cases for exterior loop antenna amplifiers
Whith a simple hole, sometimes small insects get in and the IP-class of sealed cases is lost. Thus instead of a simple hole, i prefer protective air and moisture vents. There are two versions, cheaper adhesive vents and more expensive screw in / plug in vents.
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You can purchase breathing vents in various sizes at low prices from chinese sellers:
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regards
Fred |
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Re: Some thoughts on cases for exterior loop antenna amplifiers
No mater how good the box is, if you don¡¯t drill vent holes in it you will get water in eventually.
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Everett N4CY On Friday, August 16, 2024, 5:21 PM, Dan Clementi <dan@...> wrote:
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Re: Some thoughts on cases for exterior loop antenna amplifiers
On Fri, Aug 16, 2024 at 05:26 PM, wn4isx wrote:
Clever idea on the GoreTex tape and good find on the Honeywell vent.? FWIW, I just deployed my LZ1AQ in a sealed ABS box with one of these for a breather:
I'll report on that after a while.
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Dan - K3GMQ |
Pete_G4GJL
Scott Dupuie
Everett N4CY