No, polystyrene capacitors have LOWER maximum temperature capability than most other capacitors; that is one of their limitations. But they have very low leakage, last forever if not mistreated, and are cheap.
Tempco is shorthand for temperature coefficient. It describes how much the capacitance changes as temperature changes. Some capacitors change very little (for example C0G ceramics), others change a LOT (Z5U ceramics).
-- Jim Mueller wrongname@nospam.com To get my real email address, replace wrongname with dadoheadman. Then replace nospam with fastmail. Lastly, replace com with us.
No market. Everything now is built on PC boards and axial lead parts take up too much room. Some axial lead parts are getting hard to get.
-- Jim Mueller wrongname@nospam.com To get my real email address, replace wrongname with dadoheadman. Then replace nospam with fastmail. Lastly, replace com with us.
Agreed. You've given up before you've even started looking for a solution. We have about 5 small and one large wireless ISP's in my area that provide reliable service for your situation.
Duz this neighbor have high speed internet? If so, a point to point wireless link will get you internet.
Can you "see" this small town from your rooftop? From a nearby hilltop on your property? From the top of a tree or tower? If it has high speed internet, as seems to be the case since the local coffee shop does have it, you can establish a similar point to point wireless link, or find a WISP to do it for you.
That's a bit too far.
I live in a hilly area with lots of tall trees. Cellular coverage is spotty in many places. So, I arrange to have someone install either a nanocellular base station from the cellular provider, or a yagi antenna on the roof pointed at the nearest cell site. (I gave up tower and rooftop climbing about 15 years ago).
I've been mildly involved in several neighborhood campaigns to "convince" the incumbent service provider to provide internet. If they want a franchise from the city or county, they'll have to provide service extension for those that are willing to pay for it. For example: Get your neighborhood organized and be prepared to make some noises when your local cable franchise is scheduled for renewal.
Only way? You're ignoring almost everything I previously suggested. I suggest you do some research into wireless internet before declaring your situation as hopeless. If you're lost, the email address in the signature works. If you're desperate, so does the phone number. I just hate to see anyone suffer with only dialup.
$70/month after the teaser rate expires. No TV required. You can possibly dump your phone service and switch to VoIP or use their phone offering. You can get a similar prices from: You'll need to buy satellite equipment and have an authorized installer do the dish installation. Not sure of the prices.
-- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558
No, they are Amish. Almost all my neighbors are Amish, except for one very old retired farmer who I doubt even knows what the internet is.
I can not see it from my rooftop. There is a woods between my house and the road. But even without the trees, I could not see the town, unless I drive to the top of the hill (I live in a valley). My land ends at almost the top of the hill, and I can probably see the town if I was to climb a tree, or even stand on top of a full hay wagon full of hay. But if I go another 50 or 70 feet higher (up the private road), I can easily see town. (If this is not making sense, my driveway is a shared private road. Between the county road and my farm, there is cropland. The driveway is shared by myself and the farmer who owns that land. (He does not live there, it's just crops). This roadway (driveway) is 2/3 of a mile from the county road to my house. [and, yea, I have to plow the whole friggin thing when it snows].
Yes, that town has high speed internet, and has public WIFI at the library and at a fast food restaurant. As well as a lot of secured WIFI signals (at businesses) that I can see on my laptop, when I am in town. I regularly sit in the parking lot at that restaurant and use the WIFI from my car, even when they are closed.
You lost me, when you started talking about "point to point wireless link, and WISP".
I was looking at those cellphone boosters on ebay. Since I can get a semi-usable signal on the roof, I thought about putting a yagi antenna on my tv antenna tower and running that into the house. Part of my problem is having a house with metal siding and roof.
Getting my Amish neighbors involved is not gonna happen :)
But I did sign a petition to get better cell service, after I raised hell with some of the law enforcement people in the area. This occurred about 20 months ago, when I saw a building on fire in another small town nearby. I had a vehicle breakdown, and I was unable to call anyone for help, because there is no cell signal at all in that town. So, while I'm trying to fix my truck in cold weather, I notice a building on fire a block away, and I cant even call the fire dept. This was during the night, that town consists of about 100 population and no one drives up that town's roads during the night. I finally woke someone up by banging on doors, but by the time they called the fire dept, that building was a total loss.
After I bitched like hell to the fire dept and other law enforcement, that petition was created. It was passed around that town and other nearby small towns. It was at the bars and public buildings, and got around 250 signatures. The cell company in the area said they were planning to build a new tower. (But from what I have heard from the locals, they said that same thing 10 years ago). Nothing has changed.
I hate having to cope with dialup, and worse yet, I can not establish a decent connection using my US RObotics modem on any computer with Windows XP. I can only connect using Window 98. I dont mind Win98, in fact I like it, but the newest browser I can use if Firefox 3.x. At least half the websites no longer work for me. So I mostly just use usenet and email most of the time now, but some websites still work. If they dont load after 10 minutes, I know they will never load.
I may be emailing you soon....
The modern equivalent of the Amish are people who claim to be "electro-sensitive". A former lady friend was like that. I didn't recognize the similarity until now. Thanks for the hint.
I suspect that the aesthetics of a 50ft radio tower would be a show stopper with the local planning department. However, if you can get past that, you would end up with a radio tower with one end of a 2.4 or 5GHz wireless bridge with the other end in town with someone who has high speed internet. Ideally, the backhaul from the tower to your house would be buried cable or fiber, but can also be wireless. More commonly, there's a 2nd wireless radio on the tower to distribute internet to the neighbors, but that doesn't seem to be a requirement here.
WISP is "Wireless Internet Service Provider". It's just like a conventional cable or telco service providers, but without the wires. Instead of you building the tower and negotiating for sharing broadband, the WISP does this for you.
Point to point wireless is basically a wireless bridge. I'll spare you the details, but here's an example: Think of it as an ethernet network extension cord without wires.
The legality of some of those boosters are questionable. They're also expensive. I have one made by zBoost. Of course, I couldn't resist tearing it apart and looking inside:
I had a talk last year with the local Verizon engineer about new site construction. He casually mentioned that they typically have about
2,000 new sites in progress at any time in Northern California. That doesn't mean they're building these sites, just at some step in the process, such as getting approvals from the local councils, boards, and agencies. If they meet any resistance from citizens groups, that site goes to the bottom of the list, and they continue working on those where the locals want a cell site installed. He mentioned that there were several sites where the locals offered to subsidize the construction in order to get cellular service. I suspect your cellular company meet some resistance from the local Amish, and just walked away.I used that combination for many years until I was able to get DSL. It should work. I wrote this during that era to test phone lines using USR modems:
I was afraid that might happen.
-- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558
The 470pf polystyrene capacitors used in the mpx circuits of many receivers in the 1970s used to fail all the time.
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AFAICR: the one with the paper reservoir cap was a regen.
Apparently the tempco of polystyrene is a good match for pot cores.
I've seen polystyrene crack/craze with age - I didn't investigate whether performance was impaired.
Polystyrene is pretty much the most vulnerable to solvents there is - fortunately, most de fluxing solvents were banned to protect the ozone layer.
On Feb 2, 2017, snipped-for-privacy@tubes.com wrote (in article):
Several causes listed are caused by shorted or leaking capacitors. It?s a tube killer.
A;so the sinle largest killer of hard to replace power transformers.
Not to mention a leaky grid coupling cap can pass a large DC voltage from the plate of the previous stage. I've seen tubes that got so hot the glass melted and the vacuum wrapped it round the internal structure like cling film.
If it happens in Ham gear - the PA tubes are seriously expensive.
I have put fuses on the secondaries of the power transformer on some high powered amplifiers. (On the high voltage leads). That protects the xformer as well as other parts. Line fuses on the primary are not enough in my opinion.
There are stories of Collins receivers, I forget which model, where the capacitor feeding the mechanical filter can go bad, and the result is a ruined mechanical filter, it can't handle the DC going through it.
SO that's the sort of thing knowledge that is out there for people coming to an old receiver for the first time.
Michael
What is a " mechanical filter"?
Pretty much what the name says it is.
Usually a row of disks with a mechanical resonant frequency, AFAIK: the transducers at each end were usually inductive, but I believe there were piezo types.
At one time they were the most common type of IF selectivity in Ham radio and other communications gear.
It provide selectivity in the receiver. It goes in the IF, at 455KHz or sometimes 500KHz or even I have one at 250KHz. Generally for narrow selctivity, like for SSB or CW. Kind of expensive, but even more so decades later when they are no longer being made, and finding a specific model may not be so easy. So if the capacitor goes, it can be expensive to remedy.
Michael
-- Jeff-1.0 wa6fwi http://www.foxsmercantile.com
I think that's debateable.
For a long time IF transformers were "good enough" and a single crystal filter was the step up. Those were common until the SSB age in the mid-fifties, when mechanical filters became somewhat common, but multi-crystal filters also came along at that point, and within a few years the shift was to a crystal filter in the HF range.
Collins used mechanical filters in their receivers, but not all of them. Some CB sets used them, helped in part because some company in Japan made a cheaper mechanical filter, but that wsa sort of a blip, ceramic filters ame along soon after and they were cheaper. Upper end equipment tended to use mechanical filters right to the end, when Collins stopped making them a few years ago, the implied move to software radios taking over.
Some ham SSB sets used them, and I had an RCA SSB Carphone that had a
250KHz mechanical filter.But lots of other equipment used other things rather than mechanical filters.
Michael
Collins introduced them in the 75A-4 and 51J-4 receivers back in the early '50s.
Drake used a 50 KHz IF and tuned LC filters in their receivers up until the mid '60s.
The alternative to Collins mechanical filters were multi-pole crystal filters. Which was what everyone else was using.
One of the stranger things to come across was Henry Radio offered a kit to install a Collins mechanical filter in the Drake 2B receiver.
Absolutely pointless, but it allowed you to win "dick waving" contests.
-- Jeff-1.0 wa6fwi http://www.foxsmercantile.com
-- Never piss off an Engineer! They don't get mad. They don't get even. They go for over unity! ;-)
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