The cards on demarctech's site look suspiciously like the SMC 200mw card which goes for about $50. These cards are also using RP-MMCX(a pretty uncommon connector on a card, which is a pain) and have the same removable clip on antenna. If you don't already have gear the SMC high wattage card is a good deal, otherwise if you want to use other antennas you'll have to buy a cable(pigtail) for about $20, which puts at the price point for the Senao 200mw cards(that do not include that cool clip on antenna).
On 8/4/04 9:58 AM, "Jim Thompson" <[EMAIL PROTECTED]> wrote: > > On Aug 4, 2004, at 5:38 AM, Haudy Kazemi wrote: > >> There are also 300 mW (24.8 dBm) prism 2.5 cards from Demarctech. I >> haven't tried them but the specs are here: >> http://www.demarctech.com/products/reliawave-rwz/reliawave-rwz-300mw- >> prism2 >> -5-pcmcia-card.html >> http://www.demarctech.com/techsupport/rw-wireless-cards-support/100mw- >> rx-te >> st.htm >> >> Their 100mw and 200mw models sensitivity was found to be, and the 300mw >> card is probably about the same: >> -91dBm 11mbps FER<8% >> -93dBm 5.5mbps FER<8% >> -95dBm 2mbps FER<8% >> -96dBm 1mbps FER<8% > > Theoretical receive sensitivity can be calculated as: > > Receive sensitivity = Nt + Ns + SNRmin > > where Nt is the thermal noise floor, Ns is the system noise figure, > and SNRmin is the minimum SNR required for a given bit-error rate. > > 802.11b's CCK requires a SNR of about 10dB to decode frames with a FER > of 0.08. (We'll leave SIR and/or SINR out of the discussion unless > someone insists.) We'll call this SNRmin. > > All matter at temperatures above absolute zero (0K, about -460F) > radiates electromagnetic energy. The amount of energy is related to > temperature -- the hotter the matter, the more energy is radiated. This > energy is described by Boltzmann's Constant, 'k' (k = > -198.6dBm/degreesK-Hz). This constant, multiplied by the temperature of > the matter a receiver views and the system bandwidth, yields an > irreducible background noise against which a desired signal must > compete. This is thermal noise. > > For the purpose of this exercise, lets use 80F, or about 300K (T=300K). > RF engineers typically use this number as a rule of thumb, and its > roughly the year-round temp here in Hawaii. :-) > > 802.11b uses a channel 22Mhz wide. > > Tn(dBm) = -198.6 + 10 * log10(300) + 10 * log10(22,000,000) = > -100.4dBm. > > Receive sensitivity = Nt + Ns + 10log(BW) + SNRmin > -91dBm = -100.4dBm + Ns + 10dB > > You can see we're in-trouble already. (Or my math is out to lunch, and > someone will correct me.) > > The thermal noise floor is at -100.4dBm, we require 10dBm of SNR, and > someone has promised us -91dBm rx sensitivity. Even with a > noise-free (perfect) LNA and receiver chain, we're slightly short. > > I'll leave it as an exercise to the reader to fill in the noise figure > for the LNA and Prism-II receiver on the Zcom designs. They'll be > listed on the datasheet(s) for the part(s). > >> That said, the extra power may or may not make a difference in your >> ability >> to talk to an access point, depending on the AP's own sensitivity. >> (If you >> have a powerful but insensitive AP, this card may help.) >> >> Note: there was a way to overdrive the 200mw Senao cards to 249mw >> using one >> of the linux drivers. > > Its a huge mistake to do this, and not just for the obvious legal > reason. > >> Maybe the 300mw cards can go even higher...or maybe >> like when overclocking cpus, the higher spec chips are simply the >> higher >> grade cut of the chip production line. > > This is what Tony would like you to believe, but its not true. > > 3054 is 21dBm in 11b modes. (+/- 2dBm) > >> >> Aries info links: >> review: http://ben.pfountz.com/~bpfountz/3054CB.html >> http://www.netgate.com/3054CBARIES.html >> http://www.netgate.com/New/NL_3054%20CB%20Aries.pdf >> http://www.hautespot.net/products/datasheets/nl-3054%20cb%20plus- >> spec.pdf >> Atheros AR5212 baseband, AR2112 radio >> Typical TX Output power upto 21dBm / 126mW >> >> On 4 Aug 2004, crispin wrote: >>> The Senao cards are some of the best, check out netgate.com for >>> descriptions. They are available with or w/o buit-in antennas. Until >>> recently they were among the highest powered "B" cards w/200mw of >>> power(compared to an Orinoco or mant other at about 32mw), they have >> great >>> sensitivity as well. They also use a standard Prism chipset so they >>> play >>> well w/other gear. You should be able to pick one up for around >>> $70(just >>> saw that they're on sale @ netgate for $65). That site also has a >>> good >> "G" >>> card based upon the Atheros chipset, the Aries, which is 100mw(high >>> for a >>> "G" card"). They also have the same cards available in a mini pci >>> form, >>> enjoy. crispin >>> >>> >>> On 8/3/04 2:59 PM, "Philip J Robar" <[EMAIL PROTECTED]> >>> wrote: >>> >>>> On Aug 3, 2004, at 1:36 PM, Randy S wrote: >>>> >>>>> I'm looking for an 802.1b, g is optional, ext. antenna jack is >>>>> optional, pc card that has great reception with just the built in >>>>> antenna. >>>>> >>>>> Can anyone recommend a good card or a good site with some tests and >>>>> reviews of hardware? I'd like to upgrade from my current Netgear >>>>> MA401. >>>> >>>> http://www.practicallynetworked.com >>>> >>>> Phil >>>> >>>> _______________________________________________ >>>> BAWUG's general wireless chat mailing list >>>> [unsubscribe] http://lists.bawug.org/mailman/listinfo/wireless >>> >>> >>> _______________________________________________ >>> BAWUG's general wireless chat mailing list >>> [unsubscribe] http://lists.bawug.org/mailman/listinfo/wireless >>> >> >> >> _______________________________________________ >> BAWUG's general wireless chat mailing list >> [unsubscribe] http://lists.bawug.org/mailman/listinfo/wireless > > _______________________________________________ > BAWUG's general wireless chat mailing list > [unsubscribe] http://lists.bawug.org/mailman/listinfo/wireless _______________________________________________ BAWUG's general wireless chat mailing list [unsubscribe] http://lists.bawug.org/mailman/listinfo/wireless
