Call Search
     

New to Ham Radio?
My Profile

Community
Articles
Forums
News
Reviews
Friends Remembered
Strays
Survey Question

Operating
Contesting
DX Cluster Spots
Propagation

Resources
Calendar
Classifieds
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
About eHam.net



QSL Managers
     

Ham Links
     


  Home Help Search  
  Show Posts
Pages: Prev 1 ... 4 5 6 7 8 [9] 10 11 12 13 14 ... 147 Next
121  eHam Forums / Elmers / Using V/UHF Dummy Loads/Watt/SWR meters on HF... on: June 27, 2007, 08:44:29 AM
As statd above, the meter reading may not be accurate at frequencies below the rated minimum; it's the meter circuit that has a frequency lower limit.
    The dummy load itself will work perfectly well, as long as you do NOT exceed it's power dissipation rating, which could ruin it's usefulness at HF OR VHF/UHF.  And if it's rated for intermittent use, it's even more important to be careful about not exceeding it's power rating.

    But hams are famous (notorious?) for using equipment above and beyond it's rated specs.  The trick is to understand that equipment used for other than it's intended purpose requires the user to interpret the result of that use, and prevent damage along the way.  In this case, your meter could well give a false reading, and you should use other means to measure power.  But unless you exceed the actual power rating of the device, there should be no damage.
    (Look at it this way:  If the physical meter were damaged or missing, you would still have a usable dummy load.  A ham should be able to understand, or learn to understand, that that portion of the equipment will still function properly.  Blindly saying "you shouldn't use a piece of equipment outside it's design range" as stated above is disingenious.  It's a matter of knowing what to expect (and what NOT to expect) when you think (or use) equipment "outside the (black) box."

    Good luck, and don't be afraid to ask questions when you feel the need.
122  eHam Forums / Elmers / Field Day Strategy on: June 19, 2007, 12:41:50 AM
I've participated as a single op/home emergency power, as well with clubs that are amoungst the "sit around and eat" crowd, as well as a "no time to eat; get those point" group.

    I have to say I feel there should be a balance, but the "sit around and eat" club seemed to be the best of the bunch.  there were plenty of multi-band operations set up, both CW and phone, some digital, and some satellite, for the bonus points.  But the real emphasis was NOT sheer number of points; it WAS getting the public to notice the operation in a City park, and introduce non-hams to Amateur Radio.  Point score was NOT the "be all, end-all" reason for the set up.  Really, more enjoyable than a cut-throat contest type of setup.  And it DID allow for some socialization, without some FD Jockey/Coach yelling "get back to work" when making a pit stop.  I don't feel bad about leaving THAT organization.  Sadly, FD is nothing more than a contest at this point in time.  True emergency preparedness would put much emphasis on VHF/UHF communication for local comms and coordination; HF isn't justified for local disaster relief.
123  eHam Forums / Elmers / VHF Cable Length on: June 19, 2007, 12:18:42 AM
Regardless of all the replies telling you to use "such and a such" a cable, or telling you "not to use" such and such a cable, or even telling you are doing things all wrong, the answer to your question is:

1.  You WILL suffer signal loss either way you describe.  
2.  9913, if properly installed and weather-proofed is not a bad choice, especially on 2 Meters, assuming it's fairly recent manufacture, and not 20 years old.
3.  The difference in loss between 100 and 140 feet won't be noticable if all you want to do is contact repeaters.

    Yes, there WILL be greater loss with the 140 foot run.  40% more, in fact.  But the difference in loss will be less than 1 dB at 2 Meters.  THAT won't be moticable, nor would going to a slightly lower loss cable such as LMR-400  .  If you already have the cable, do what ever you wish.  Your ability to communicate effectively with repeaters will not differ.  If you were REALLY working weak signal, such as CW/SSB, you would be investing in hardline anyway, but that's an entirely different subject.

    You should do fine with what you have.
124  eHam Forums / Elmers / TS 680s power cord on: June 18, 2007, 11:57:45 PM
The red and white are connected to positive, and gray/black go to negative.
    In order to reduce voltage drop at maximum current draw, Kenwood uses parallel 12 AWG wires for both positive and negative leads.  There SHOULD be fuse holders in each set of leads, tied together.  IE, the Red and White leads go to one fuse holder, which then connects to a few inches of red and white wires to connect to the positive terminal of your power source, and the black and gray go to another fuse holder, with another short length of gray and black wire to go to the negative terminal.
    If the fuse holders are no longer in place, they should be added!
125  eHam Forums / Elmers / Holes in 2 Meter on: June 13, 2007, 06:38:24 PM
Wild guess?  An image from your HF rig or even a local TV or other electronic device.  The LO form the same type of electronic device?
126  eHam Forums / VHF / UHF / 6-meter band plan on: June 12, 2007, 10:33:17 PM
N0EE on June 8, 2007    Mail this to a friend!      Let me get this correct... 50.110 "calling" frequency, and you get chewed out for "calling" cq? Not to be tooooo
offensive, but do as they do on 75 meters--tell them to go...Never mind....
======================

50.110 MHz is (by gentleman's agreement) a DX calling frequency.  That usually means Intercontinental or International contacts.  (And No, Seattle WA to Vancouver, B.C. or San Diego to Tijuana do not count as "international" DX contacts.)
    Just because YOU personally do not hear activity on that frequency (or any frequency, for that matter) does not mean it's not in use somewhere that your use might interfere with.
    50.125 MHz is the accepted domestic SSB calling frequency.

    The comment indicating it's quite acceptable or even advisable to use the area between 50.1 and 50.125 MHz because "the band is dead and nobody's on the air" is incorrect.  Again, YOU might not hear activity, but it might be there.  And if the band is "dead," then there's no reason to NOT operate above 50.125 MHz.
 

    There ARE also the "Pacific DX Window frequencies" from 51.0-51.1, and 52.0-52.050 MHz.  Hardly a such a big chunk that the band plan can't be observed.  If you want to use FM simplex, there's 50.1-52.0 MHz, even if it's shared with some repeaters.

    There's plenty od spectrum out there to use without violating the bandplan, and just because some other operators don't respect the bandplan, is not an excuse to do the same.


 Of course, gentleman's agreements are only observed by gentlemen (and Ladies.)
127  eHam Forums / Elmers / Station Identification on IRLP / Echolink on: June 12, 2007, 09:58:58 PM
The FCC rules state that the "incidental" music from a shuttle rebroadcast (such as their wake-up call) is permissible, since the intent is not to broadcast the music itself, and only occurs for a short period of time.
128  eHam Forums / Elmers / Station Identification on IRLP / Echolink on: June 12, 2007, 09:55:55 PM
The FCC rules state that the "incidental" music from a shuttle rebroadcast (such as their wake-up call) is permissible, since the intent is not to broadcast the music itself, and only occurs for a short period of time.
129  eHam Forums / Elmers / station at different location than my license addr on: June 12, 2007, 09:44:08 PM
N8UZE on June 11, 2007  

The FCC database and QRZ database need to reflect where you can reliably receive mail
=========

    Actually, the QRZ database doesn't REQUIRE anything.  The only official database is that of the FCC.  NO OTHER database has ANY official or legal standing.  The FCC only requires an address where you can receive mail; if mail is returned to THEM as "undeliverable" or "NOT AT THIS ADDRESS" your license can and will be suspended.  But that address does not HAVE to be your own; it could be that of your third cousin once removed.  Just as long as postal communications from the FCC are not returned to them.  (You don't even HAVE to receive them, but if you fail to reply at a letter from the FCC, you will be in even more toruble.)
    Obviously, you DO want to have a current mailing address on file because of the legal requirement, but as also suggested, you presumably want to be able to  receive QSL cards and the like.  Your address given to the FCC is a matter of public record, and the other callsign databases get their information from the FCC.  If for some reason you don't want to list your street address, or your regular "mailing address" is removed from your operating location, many hams use a Post Office Box for such correspondence, including that from the FCC. That's perfectly OK, as long as you check the mail.  (One example would be a person who is assigned to a work location for a long period of time; even if they don't give up their home residence, they might want to get mail delivered to their temporary location, and a P.O. Box can be most suitable in such a circumstance.)
130  eHam Forums / Elmers / Conversion of IC-T7H FM Transceiver to Airband on: June 09, 2007, 03:18:56 PM
VA7IC on June 8, 2007    
It is illegal to modify amatuer radios to transmit on other than amateur bands in Canada. This is from the June 2007 Industry Canada Spectrum Connection newsletter.
=============

    Not sure about Canada, but there are a lot of misconceptions about this here in the U.S.:

1.  It is NOT illegal to mod a radio to receive additional frequencies; the only exception is that cell frequencies are not supposed to be monitored or listened to.  (Older radios that had cell receive capability before the las was enacted are quite legal to own or posess, but it's still illegal to actually LISTEN to cell conversations.)
2.  It is not illegal to mod a transmitter to transmit outside the Amateur bands, but it IS HIGHLY ILLEGAL to actually USE any modified Amateur transmitter outside the Amateur frequencies.
3.  Posession of a modified transmitter is NOT illegal for a licensed Amateur.
4.  While Amateur transmitters and transceivers are exempt from any "scanner laws" regarding the incidental capability of receiving transmissions or operating outside Amateur frequencies, the FCC preemption does NOT cover receive only units, or "scanners."
5.  Currently, there are very few Amateur radios that comply with NTIA standards, which is REQUIRED for equipment used ib CAP activities.  CAP participation is no longer a viable excuse for making a transmit mod to Amateur equipment.
6.  MARS (Military Affiliated Radio Service)authorized stations can (at least at present) still use modified Amateur equipment for it's activities.  Modification information can be supplied by the individual MARS (Army, Air Force, Navy, Marine) military branch, if provided with a legitimate MARS license.  Manufacturers will usually provide the modification information (where feasable)if provided with a copy of a valid Amateur Radio license AND a copy of a valid MARS authorization.
7.  Other than MARS, there's no legitimate reason for modifying the transmit portion of a radio; anything else is just an excuse.  There's really NO other justification, whether a person is an EMT, law enforcement official, fireman, etc.  Use (to transmit) of modified Amateur gear outside the Amateur bands is a violation of FCC rules.
131  eHam Forums / Elmers / Handheld and DC plug on: June 05, 2007, 08:29:02 PM
That wasn't my point at all.  A 2 Amp fuse should be more than adequate in the cig lighter adapter; the draw is inconsequential to the auto supply, but the H-T's battery shouldn't contribute anything to operation; if anything, it should be charging if the lighter socket provides 13.8 Volts while the engine is running.

    One more important consideration:  H-T's aren't necessarily designed for automotive use, and unlike mobile rigs, don't usually have much filtering or sureg protection built in.  It would be VERY prudent to switch the H-T off when starting the car, or turning off the ignition.  While no permantent damage occurred, when I neglected to do that with my dual-band H-T, the display and memory would get totally corrupted and a full reset to factory default was necessary to get the radio to work again.  It took a while to reprogram...
132  eHam Forums / Elmers / Handheld and DC plug on: June 05, 2007, 07:36:03 PM
Not quite...

    A H-T that puts out 5 Watts will take at LEAST one Ampere of current.    (12 Volts @ 0.41 Amperes = 4.92 Watts.  If I had a way to get 5 watts OUT with 4.92 Watts IN, I'd be a billiionaire.)

    It will take considerablty more than 5 Watts to run the H-T at full power.  The typical modules are only about 50% efficient at best, and the other circuitry in the radio also consumes power.  A CONSERVATIVE estimate is 1 Ampere; but it could be more.  (When I bought my 2 M H-T, it was advertised as using the least amount of current for 5 Watts [nominal; it's really a bit over 6 Watts)] of any H-T on the market; it uses 1.08 Amperes @ 13.8 Volts.  H-T's have gotten more complex, but probably not any more efficient.  A dualband H-T by the same company uses 1.3 Amperes @ 13.8 V. for 5 Watts OUTPUT on 70 cm.)
133  eHam Forums / Amplifiers / Need suggestions for mid-power amp on: June 04, 2007, 11:29:04 PM
K7PEH on May 27, 2007    
     >>>>I agree; solid state. (no excess heat in the summer)


I agree, solid state, the only way to amplify.

However, doesn't solid state, watt-for-watt, put out more heat then a tube amp. The average tube amp is a little better than 50 percent efficient and some are a lot better. But, just about all solid-state amps are only 50 percent efficient (I think).

Thus, given a 500 watt rated tube amp and a 500 watt rated solid-state amp, the solid state will generate more heat. Albeit, it is nicer heat, but indeed, still more heat.
==================

    Nope.  ONE WORD:FILAMENTS!

    Tube amps use filaments, solid state amps don't.  The power consumed by tubes is NOT figured into the power output rating of an amp, or the amp's efficiency.  As an example, an AL-811H with 4 811A's consumes 6.3 Volts @ 4 amperes each.  That's 100 watts of power given off as heat.
134  eHam Forums / Amplifiers / Alpha 76CA "Loud Bang" on: June 04, 2007, 11:16:07 PM
EWD makes a good point about shorting HV caps through a resistance.  I was figuring the caps would be discharged to a considerable degree by the time you got the amp "unbuttoned."

    It's unlikely your fireworks were caused by a bleeder resistor going out if the amp was on standby for 24 hours prior to the "big bang."  If anything, they would be under LESS stress as you tuned up and the plate voltage dropped.    If one DID open up, however, it WOULD be a possible hazard; the bleeders are also equalizing resistors for series connected filter caps.  If one bleeder resistor opens, it can lead to unequal voltage across the caps and cause one of the caps to exceed it's voltage rating.  That, bnesides the fact that the caps would stay charged WAY longer than expected.  Check the bleeders for resistance changes; if one is bad, (shorted, open, or otherwise more than 10% off the original value) it would be wisest to replace them all with new resistors; there are "flameproof" resistors available in several wattage ratings.  Replace the whole string for safety sake.
    There could have been failure of a parasitic trap in the plate connection of one of the tubes; or again, an arc in the tuning capacitor because of dust oe some sort of accumulation over the years.  A close visual inspection should at least give you a clue as to what failed.
135  eHam Forums / VHF / UHF / element length on: June 04, 2007, 10:03:45 AM
only diff is that i made it of brass instead of al.

have i still ruined it or will it really make a diff??

david/wd4kpd
==========

    As long as the element DIAMETERS are the same, there should be no measurable difference between the original AL  element and a brass element.  If it's a true K1FO design, and the element is truly insulated from the boom so there's no metal to metal contact, then corrosion due to the reaction between dissimilar metals won't be a factor, either.
Pages: Prev 1 ... 4 5 6 7 8 [9] 10 11 12 13 14 ... 147 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!