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 2 3 4 5 [6] 7 8 9 10 11 ... 23 Next
76  eHam Forums / QRP / RE: Is the KX3 all it's cracked up to be or fake? on: November 09, 2012, 05:07:13 PM
The FT-817 lacks lower current draw and weight, better selectivity, a built-in tuner and better front panel. Polar satellite passes are rather short, so if I was only going to operate satellites and tropos, I'd bring the FT-817 and still bring an HT for full duplex, since the current draw isn't the limiting factor, pass time is; perhaps I'd even bring an FT-857 instead of the FT-817 since on low passes you might need more than QRP power on an FM satellite with a portable antenna.

The Kenwood TH-F6A/TH-F7E does SSB/CW reception, and I've done satellite operation using an FT-817 and IC-7000 on the uplink and the TH-F7E (European version of the TH-F6A) on the downlink.

If I was going for a SOTA activation, I'd want a KX-3 and a Kenwood TH-D72E instead, but I'll make do with just my FT-817ND for now. (Spending limits, you know.)
The FT-817ND is and can be my HT.
How much scan time do you get out of the battery? Even if you don't like working repeaters the primary reason why I'm looking or an HT is to have something on 2m/70cm that has a longer standby time, can do built-in APRS, and finally can be used for full duplex operation on satellites.
77  eHam Forums / QRP / RE: Is the KX3 all it's cracked up to be or fake? on: November 09, 2012, 09:25:58 AM
A 7 Ah lead acid battery and an adequate solar panel weighs quite a bit more than an HT and perhaps a little spare Li-ion battery for it. I have an FT-817 and a 7 Ah lead acid battery too, and when I go hiking I leave the lead at home and bring some spare dry cell or NiMH batteries instead; I'm going to get a LiPo pack too.
The FT-817ND was the best solution when I got it, but today I would be choosing a KX-3 and an HT instead. More performance and operating time for the weight.
78  eHam Forums / QRP / RE: Is the KX3 all it's cracked up to be or fake? on: November 09, 2012, 02:11:40 AM
"Make  some contacts on the satellite passing over head in about 3 minutes."
With the FT-817 batteries run down already? The KX-3 owner could use an 2m/70cm HT if it's an FM satellite, or put a transverter on the KX-3. And if the satellite has a microwave uplink, both guys would need a transverter anyway.

The right answer to the question would be that instead of getting in a "pissing contest" they would combine their radios so that they could work the satellite full duplex (listen to the downlink while transmitting). If it was a linear transponder or inverting transponder, they could perhaps transmit with the FT-817 and listen with the KX-3s more selective receiver.
79  eHam Forums / Emergency Communications / RE: Looking For Gas Powered 12V DC Generator/Charger Advice on: November 08, 2012, 03:58:17 AM
Also consider practicality and safety: You probably have your battery bank indoors. You absolutely MUST run the generator outdoors to not contribute to the usual CO poisoning death statistics. If you were going to have a long run of 12 V DC wiring from the generator to the battery bank, at high amperage, you'd need very thick cables - perhaps costing more than the generator itself. Higher voltages transfer the same amount of energy with less amperage, meaning less resistive losses and one can use thinner cables.

If you're going to charge batteries on the "battery charging" output, it's meant for carrying the battery next to the generator, not for charging big battery banks.

Look into getting a generator with both 120 v and 240 v output by the way. Some equipment like well pumps, sump pumps, etc. actually run on 240 volts.

For a more gee-wiz, but far less efficient, way of getting 12 volts, you could look into Peltier elements.
80  eHam Forums / QRP / RE: QRP PSK rig on: October 23, 2012, 06:10:25 PM
The KX-3 decodes PSK-31 on-screen, but you have to use the morse key to enter the text. Unless you're fast at CW, until somebody "hacks" it to plug a keyboard straight into the radio, you still need an external modem or computer for practical operation. Any QRP SSB rig should be usable for PSK-31 with a modem, as far as I know.

NUE-PSK is a PSK-31 box that you just connect to the radio and keyboard - no extra computer needed. It is available pre-assembled and tested if you don't want to build it.

If you have an iPad, there are PSK-31 apps for it. If you have laptop or netbook, put flDigi on it.

North West Digital Radio are developing a 70 cm radio with a built-in Linux server; that might turn into something interesting for HF QRP'ers too in the future.
81  eHam Forums / RFI / EMI / RE: NB and NR Performance Comparisons? on: October 15, 2012, 01:26:21 AM
The NB on my FT-817ND does make the wideband electric fence pulses more bearable, but it doesn't cancel it completely. The pulses are like clockwork, so I guess that helps the NB, but they're S9 so perhaps more than the ignition noise that the NB was meant to deal with.
82  eHam Forums / Antennas and Towers and more / RE: dipole attached to the top of a verticle antenna - can this be done on: October 10, 2012, 03:18:53 PM
Yeah as far as I understand, the typical thing is to have - say - a 20 meter beam, or perhaps a trapped beam for 20 to 15 meters on a tower (substitute for a 20 meter dipole if you want less directivity), and then load up the tower itself for - say - 160 meters vertical. Rather than isolating the tower from ground (which would be hard to do with that feedline going to the beam), what you do is keep the tower grounded but move the feed up and down the tower, you tap it, combined with adding capacitance or inductance, until you get a close to 50 ohm + 0j  impedance on your chosen frequency.

Note here that one usually does this with bands that are far apart. Putting a dipole on top of a vertical of the same band, or a nearby band, would lead to the problems that K0ZN's post is about

Check out Tom's webiste W8JI.com - there's plenty of information there. For example here: http://www.w8ji.com/omega_and_gama_matching.htm or in the ARRL Antenna Book.

PS: W9GB, are you sure you responded to the right thread?
83  eHam Forums / Antennas and Towers and more / RE: 2m/440 vertical - coupling and static question on: October 09, 2012, 12:26:10 PM
Note that although you have DC continuity on the coax joint, you might have a signal reflection point there (if the coupling is not of the same impedance (reactance and resistance) as the coax, it will cause some reflection)). Your length of coax might be "just right" for a problem to occur as well.

As well as the suggestions above, try one coax at a time, and try moving the antenna.
84  eHam Forums / Station Building / RE: Flourescent or Incadescant? on: October 05, 2012, 07:54:20 AM
I think in most countries in Europe, all stores which sell CFLs are required by law to take used ones back, and there are municipal recycling points as well.
85  eHam Forums / Emergency Communications / RE: Whats in your "GO Box"? on: October 05, 2012, 04:09:55 AM
No, it's not true. He's drunkposting again.  Roll Eyes
86  eHam Forums / Station Building / RE: Flourescent or Incadescant? on: October 04, 2012, 06:22:56 AM
I did have a couple of CFL's go bad so I threw them in the trash.
Please don't throw them in the trash. CFLs require hazmat handling, so deliver them to a recycling point for CFLs.
87  eHam Forums / Station Building / RE: Flourescent or Incadescant? on: October 02, 2012, 03:38:07 AM
Except for the height of summer here in Norway, and outdoor lights, replacing incandescents with CFLs is actually causing more emissions. For those with only electrical heating, the electricity usage savings is zero. The place I'm at right now is heated with fossil fuel, while the electricity is mostly hydro power (and some nuclear from Sweden), which means CFLs cause more emissions both by replacing hydro power heating with fossil fuel heating, and more emissions caused by production and hazmat handling.

In winter, the only houses that might be causing less climate effects without incandescents might be those heated by wood burning, high efficiency ground-to-water heat pumps, or municipal waste heat.

And then there's the spurious radio emissions. (For those in the UK, don't look to the government for regulation of this either - Ofcom is completely useless as a government agency, as unless the manufacturer has defined their product as a radio, it could be used to hold DX QSOs on public service frequencies without Ofcom caring about it.)
88  eHam Forums / QRP / RE: FT 817 and solar power on: September 26, 2012, 09:32:27 AM
If you get a small panel (7W maybe?), I hear you can live with the panel having an open voltage higher than what the radio accepts - the current draw from the radio causes internal resistance which lowers the voltage that the radio sees.

The FT-817ND is pretty forgiving with input voltage, but connecting a higher wattage panel directly is not a good idea. You will need either a solar charge controller for a sealed lead acid battery (avoid MPPT types, they tend to be RF noisy, heavy and expensive - use a simple resistive type), or something like a LiPo laptop/netbook battery pack. The latter will accept a direct connection to a solar panel, and charge an internal LiPo battery which again will charge a variation of netbooks/laptops, 12 volt, 9 volt and USB (5 volt) devices.

Here's one such battery pack (Energizer XP8000) used with the FT-817ND - looks pretty neat: http://www.youtube.com/watch?v=IsvPOyn0LeQ

A list of possible candidates:
- Powergorilla
- minigorilla
- Energizer XP8000
- maybe Energizer XP1800 <- Not sure if the voltage regulation on this will work with the FT-817ND

Tom's Hardware has a thorough review of these models here: http://www.tomshardware.com/reviews/notebook-battery-external-power-supply,2821-9.html

I have seen several different brands of solar backpacks.  They usually are 4 watts.  Can they be used to charge the ft-817nd battery?  check out http://www.amazon.com/s?ie=UTF8&page=1&rh=i%3Aaps%2Ck%3Asolar%20backpack
Those backpacks are only for USB charging, it seems - too low voltage for the radio.
Not only charging the FT-817nd, I would also like to charge my cell phone and mp3 player)
Then one of those LiPo battery packs seems like an ideal solution, given that they have both a USB port and many other outputs running off the same battery. You strap the panel to your backpack, and connect it to the LiPo pack, without having to have it connected to the radio all the time. Also you could bring some spare internal NiMh packs. (If you want to play around with internal LiPo and LiIon packs that is a possibility if you understand the dangers involved).
89  eHam Forums / QRP / RE: QRP for Preppers. on: September 19, 2012, 08:11:43 AM
Tom, you just typed 65 words about how you didn't want to type 8 characters. You could forget about it, have your browser remember it, and just request a password reset the next time you need to use it.

Password strength requirements are needed not just to protect the users - who might not care - but protect the forum owner and the server owner (and the colocation facility, by extention) from automated mass password guessing attacks.
90  eHam Forums / Emergency Communications / RE: FLARQ this weekend on: September 18, 2012, 04:45:57 AM
I'm not sure why one would use it with PSK31 since PSK31 performs very poorly under high noise conditions. 
True, on HF you'd typically use something like DominoEX 22, Olivia 8/500 or Olivia 16/500 for NBEMS, but those are wider signals than PSK 31, so while he's just sitting there throwing out his beacon (basically the computer is sitting there CQ'ing away every 30 seconds) at least he's not taking up more bandwidth than necessary. Presumably, once he gets a connection from another station they could agree to change modes to a wider mode for file transmission (be it radiogram greetings, or other test data). flARQ has a live plain talk field as well as the file transmission field so you can chat with the operator while you're setting up the file transfer.

For testing, you can do audio frequency file transfers between two computers in the same room.
Pages: Prev 1 2 3 4 5 [6] 7 8 9 10 11 ... 23 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!