Call Search

New to Ham Radio?
My Profile

Friends Remembered
Survey Question

DX Cluster Spots

Ham Exams
Ham Links
List Archives
News Articles
Product Reviews
QSL Managers

Site Info
eHam Help (FAQ)
Support the site
The eHam Team
Advertising Info
Vision Statement

donate to eham
   Home   Help Search  
Pages: [1] 2 3 4 5 6 ... 10 Next
 on: Today at 05:43:50 AM 
Started by KG5AJX - Last post by N8YX
It is also remotely possible that antenna could collect some x-ray energy and route it to HT internals. If this is a factor you could remove antenna before x-raying.
You're dismissing one key factor with that "theory". I'll let you tell the rest of the board what it is.

 on: Today at 05:39:39 AM 
Started by KB1KTF - Last post by N8YX

Just stop.

To the OP:

The shortcomings of the Astrons - namely, the efficiency of their pass transistor and regulator circuits when run close to their rated current capacity - are well known and are well documented. An RS-20A - as delivered from Astron - is insufficient for use with a 100w class rig when said rig is operated at full power...particularly when an antenna mismatch occurs and allows a PA without proper SWR foldback control to deliver more than its nominal ratings, thereby increasing current load.

You've posted this same request for help at several places around the 'Net and are getting the exact same response in every case. Upgrade your supply to something with more current headroom, and fix the existing one for use with a lower-power rig. A few posters elsewhere even gave you step-by-step instructions on how to troubleshoot it.

 on: Today at 05:30:21 AM 
Started by W8JX - Last post by W3WN
Interesting comment posted to the CQ Contest reflector this morning... as they say, food for thought...
< snip >XYL and I stopped at a local restaurant Saturday afternoon and visited with the
manager. We talked about the Hamvention a little.

He indicated a lot of local business were really disappointed in how few hams stopped in their business when the community tried to roll out the red carpet for us.

This particular person use to be manager at some restaurant by Hara and said they were always full of hams during Hamvention so he was surprised to hardly seen any.

I can come up with a couple of reasons for not hitting the local restaurants, such as all the good food
choices at Hamvention and it not being as easy to run out to the local restaurant as it was at Hara. Another is the new location my focus was just learning and figuring out how to get there.
< snip >
Can't speak for anyone else, but now that I know my way around Xenia a little bit, I'm going to make it a point next year to stop for dinner on the way back to the hotel somewhere. 

 on: Today at 05:28:40 AM 
Started by W4KYR - Last post by N8YX
I likely know more than you ever will
Just stop.

and I was a operator before you were even born
I believe they call this "Silverbacking". Also...for someone who knows more than the rest of us, can you explain why you constantly butcher the English language in your postings?

and used many rigs that were not no tune plug n play like today and some I even built. (show some respect)
Respect is earned on the basis of deeds, not on that of runtime. Kindly publish the schematics and operational theory of something you designed (not copied) and we amateurs as a group (not just Eham members, mind you) will evaluate your engineering prowess.

...from HT's with spectral purity issues actually interfering with communications. But some like ZIM thinks that the HT purity BS sells well and is a BIG problem and talking about it makes them sound "expert" like....
I know what my spectrum analyzer tells me about certain makes and models of equipment. What does yours say?

 on: Today at 05:28:39 AM 
Started by KB1KTF - Last post by W8JX

The bolded is likely your problem. At 100w output, you're running that supply at or near its maximum ratings...which - due to their overall design - Astrons don't particularly care for. The right (wrong) set of circumstances came together on a power peak and out it went.

Find yourself a used RS-35M and I doubt you'll have a recurrence. Then fix your 20A unit and use it to power your 50W VHF/UHF FM gear.

What a hunk of BS. YOU DO NOT NEED A RS-35 DOOR STOP.  I used a RS20 for over 25 years with a TS-140, TS450, TS850, TS480 and a TS570. I still have 480 and 570. I also powered dual band rigs and a TNC from supply too at same time (dual band rigs on receive) and never had a problem. Today my RS-20 is a backup and has been replaced by a smaller, lighter and more efficient SS-30 power supply (much cheaper than a RS35 too) There are also some miss conceptions about power supply ratings. A RS20 is rated at 16 amps continuous and 20 amp at a 50% duty cycle and it does not quit as 20.5 amps either. SSB duty cycle does not even come close to 50% duty cycle rating as average power is about 8 or 9 amps when talking and duty cycle is based on average not peaks. BTW I did use about 100,000 ufd of capacitors in parallel with load to soften surge/peak load on power supply during SSB.  

 on: Today at 05:19:07 AM 
Started by N6YFM - Last post by N2DTS
The same could be said in comparison between ssb and CW.

Both radios will work fine as long as you are likely to want to use them.
I even hear the original Flex 1000's on the air.
And a lot of Icom's are in the landfill due to display problems...

Why not just get the radio you like best?


7.  Please don't talk to me about AM :-)   Take a look at your panadapter on 20m or 40m and show me where there
is room on these crowded bands for wide, obsolete modes?  Oh, um, there is probably a lot of room for them on 10 and
11 meters, sorry.   Even more room on 6m.  That said, my Icom 7300 did just fine on the recent A.M. Rally, I actually heard
and made almost a dozen contacts, using A.M.   That's it.  One dozen, out of ~750,000 USA hams.    Since SSB fits in less
than half the bandwidth, is still understandable, and has a 9dB advantage, it's almost like virtually having "Kilowatts for Free".
Please don't worry me about A.M.  :-)  A.M. is not energy efficient, it is not bandwidth use efficient, and it will NEVER
be Energy Star rated :-)    But if you really need a ballast load for that 150 KW Santa Fe Diesel Generator in your back yard,
go ahead and key up your A.M. Amplifier for a rag chew.

 on: Today at 05:18:09 AM 
Started by KG5AJX - Last post by W8JX
I think where the risk of damage increases is as the die size in IC chips used in newer HT shrink, they get closer to the size the wave length of some x-rays used and therefore absorb more energy. Older HT's have much larger dies sizes in IC chips and are not effected by Xrays as easily. It is also remotely possible that antenna could collect some x-ray energy and route it to HT internals. If this is a factor you could remove antenna before x-raying.

 on: Today at 05:09:16 AM 
Started by AA4N - Last post by AA4N
Well, I got those study results translated, and I was able to ask a few follow up questions as well.  Here's the short version;

All of the tests were done using calibrated test gear.   The glass samples had all been ground to a uniform 1mm thickness.   The various types of glass in the test were all batch tint types, no coated glass.   Both green and privacy gray tints.

The results were that there isn't much variation to speak of.   The variation was less than the 20% that you might see in common electrolytic capacitors.

Bear in mind that these tests were done in Japan, and there are slight differences in the make up of the batch over there from what we mix up here in the US.

All of that being said...   I also did some google research on this term "passivated".   I had never heard that term before in the industry.   What I found was a good bit of discussion about glass that has had a coating applied to it.  Frequently with regard to bits of glass used in microchip or electronic component manufacturing.

This brought to mind a time, back around the mid 90's when Ford was making a lot cars with mirror like coatings on the glass behind the B-pillars.   I remember seeing a lot of Explorers with that "Smokey and the bandit" mirrored sunglasses look going on.   I also recall a lot of Pontiacs with the metallic purple coatings on the windshields.   I've got a sneaking suspicion that those coated products are what Larsen was talking about when they mentioned "passivated" glass in their literature.  I don't think anybody is doing that anymore.   We certainly never used coatings.   That stuff is expensive, fragile, and kind of goofy looking.

My take away from all of this is the following;    If you would like to try a through-glass antenna, your best chance of success will be had by putting it on tempered glass (not the windshield), that doesn't have any plastic film tint, or any metallic tint coating from the factory.  You also need to stay away from any of the screen printed features like the black band around the edge and the silver heater grid and antennas.   Regular green or gray tempered glass will likely work as advertised.   But, an NMO mount in the middle of the roof will probably work better Smiley

Nuff said...

73  mike

 on: Today at 04:49:16 AM 
Started by N4SRN - Last post by G8HQP
There is a slight danger with multiple wires of similar but not identical lengths that between two low impedance resonances you will get a high impedance resonance. Whether this will be a problem in practice depends on details.

 on: Today at 04:44:36 AM 
Started by M6WVI - Last post by G8HQP
I have just read your first post more carefully. Did you buy the wire but not the feedpoint?

For a passive antenna on 2-30MHz you basically have two choices:
1. poor performance at some frequencies, good performance at others
2. poor performance at all frequencies.
Fortunately, for HF reception you will be limited by noise so good performance is not needed. As the antenna impedance will be high at most frequencies a 4:1 or 9:1 balun may help.

If you want to transmit then pick a frequency, cut it for that (using a 1:1 balun), and accept poorer performance for reception at other frequencies.

Pages: [1] 2 3 4 5 6 ... 10 Next
Powered by MySQL Powered by PHP Powered by SMF 1.1.11 | SMF © 2006-2009, Simple Machines LLC Valid XHTML 1.0! Valid CSS!