[amsat-bb] Re: is it really QRP making the difference
n3tl at bellsouth.net
Wed Dec 17 09:51:30 PST 2008
Jim and all,
Great points, and all very well-made.
My choice to take the approach I have is just that - my choice. This isn't my first time to the ol' ham radio rodeo, either - and I am well aware of the compromises I inevitably must deal with, and of the need for the patience and understanding required to achieve whatever success I have, and will as I move forward.
Thank you for a very thoughtful and well-written post.
73 to all,
Tim - N3TL
-------------- Original message from "Jim Danehy" <jdanehy at cinci.rr.com>: --------------
After 4 months of working the satellites I have the following observation . . .
> I have QSLed close to 300 stations with great response (thanks for confirming close to 200 Grid Squares) . . . most but not all of those QSOs were North American stations . . . . many (but not all) QSLs indicate the type of antenna that was used . . . my statistics show that about 2 out of 3 are using some compromise antenna . . . definition of compromise antenna : Elk, Arrow, Eggbeater, Vertical. They are compromised compared to a Yagi or Helix antenna.
> Some of the compromised antennas are further impaired by being used indoors.
> I have often worked K9CIS on either FO 29 or AO 7 when Frank was running milliwatts and I had an armchair copy on CW. He was not running compromised antennas. FM mode is the mode of choice for most. Those using FM must realize that there is a difference on how FM receivers work. The strongest signal captures the discriminator and comes out on top compared to a competing signal.
> That does not occur on SSB or CW. Frank, K9CIS and Mike, K9QHO further assisted
> me when I got on in August with my use of a dual polarity yagi. . .this type of
> antenna mitigates the constantly changing polarity heard by those using linear
> (vertical or horizontal) polarity. . .
> Many of those compromised antenna users also use QRP power levels ( 5 watts or
> less). . . . when I got back into satellite operating from a 30 year hiatus, I
> noted the advertising for the Arrow and its use with an HT (QRP) rig. That was
> certainly novel and interesting from my 56 years of operating sometimes with
> stacked yagis on HF and VHF. . . My receiving antenna for satellites has 14 db
> of gain and dual polarity . . . well 13 db of gain is equivalent to a multiplier
> factor of 10 for 10 db and double that to 20 for the extra 3 db. A friend of
> mine has used the Elk and the Arrow. He could not carry on a cross town QSO on
> 435 mhz using the Elk so he sent it back.
> I often make QSOs into France, UK, Netherlands and Belgium on AO 7 using my
> antennas at an elevation of 1 or 2 degrees. I can hear very well with these
> antennas. Something that a compromised antenna can not do. [ transponder
> satellites] AO7 , FO29, VO52. . . turn on a preamp and it gets even better
> for the transponder operator . . . you do not use a preamp on an HT . . .
> With 5 watts (QRP) on FM and a 10 db transmitting antenna my ERP is 50 watts .
> . . . and an HT @ 2 or 3 maybe 5 watts to a compromised antenna maybe is lucky
> to get 6 db gain (a factor of 4) . . . for an ERP of 8 to 10 watts and linear
> polarity (another compromise) which can reduce the ERP during a pass by a factor
> of 3 db (half) . . . cutting the HT's operator's power to 4 or 5 watts . . .
> compare that to my 50 watts ERP ( 5 watt station ) with no compromise antennas
> used both on FM and Transponder satellites to the HT operator . . you will see
> that it is not QRP levels but antenna efficiency and effectiveness that is the
> BIG difference . . . QRP operating refers to the power not to the antennas being
> used . . . I think folks need to reflect on what QRP operating is compared to
> QRP and compromised antennas . . .
> Using an HT is OK but do not expect it to compare to the same 5 watt power level
> and a set of yagis . . . 5 watts is still 5 watts for either station . . . the
> difference is the antennas. . . . . yes it is novel and good PR to see HT users
> use the satellites . . . . . reality is something else . . .
> A pair of yagis with dual polarity (not linear polarity) and ACCURATE TRACKING
> is still another advantage that is compromised by the hand held antenna . . . I
> have seen operators wave the antenna and twist it around . . . well it works . .
> . the yagi operator using elevation and azimuth rotors can set his antennas to
> the correct positions within a couple of degrees . . . . that is another
> advantage over a compromised antenna . . . .
> yes there is a lot of passion by the Davids out there who want to outdo the
> Goliaths . . . that is human nature . . . if both are running 5 watts ; the
> increased gain , tracking and superior polarity all add up to grabbing the FM
> receiver in the satellite and shutting out the less advantaged station running
> the same power but with inferior antennas . . .it is the antennas not the 5
> watt QRP that makes the difference . . .
> Probably 20 % of the FM users have the superior antennas compared to those with
> compromised antennas . . . . so often the compromised antenna user feels good
> and being able to compete (against other compromised antenna users) for QSOs . .
> . in the situations where they run into a user who does not have a compromised
> antennas they should understand the situation for what it is . . . it is not
> QRP against non QRP it can be the antenna
> hearing is another issue . . . i call stations that I want to add to my Grid
> Square or country total like every one else . . . others do not hear the DX
> stations i call . . .i can get multiple stations replying to my call . . .
> others get upset . . . . remember what compromise means = PATIENCE and
> UNDERSTANDING. . . . thanks for reading , I hope this helps some understand the
> reality of the situation . . .
> Jim W9VNE
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