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Re: Fwd: Helix Feed with Cup--Dimensions



Hi Ed.
Please tell Mike "hello" for me next time you see him.  He was my first AO-40 DX :-)

> Nice photos of your dish/cavity-helix feed.  It looks like you are using a
> preamp, but I'm confused by the Drake output coax going to the preamp and a
> third cable out of the preamp.  Or is this not a preamp?

It is a Conifer PA-1033 MMDS preamp, rated at 10 dB gain with 1.0 NF.  My "amateur" observations are it does not improve the system gain by more than 6 dB, but the lower NF (my Drake tests out at 5.5) does make a noticeable difference.  The device is made to be a drop-in for the MMDS d/c by routing the power (12 Vdc up the cable) thru the preamp to the d/c.  It's a pretty slick arrangement, but ultimately analogous to the tee arrangement discussed here last week for powering the DEM and DB6NT preamps.  I bought it on eBay about 1-1/2 years ago and I saw another one sell there last week.  I plan to replace it:  ordered a DEM ULNA kit.

> Good photos giving the view from your tower.  Looks like maybe 40-50 foot
> and above tree tops?  I had no idea that there were that many trees in Texas!

It is actually about 35 feet, right at the tip of my roof, but my lot is about 15 feet above and backs up to the 10,000 acre George R. Bush "Park":  an ACOE flood reservoir, for all intents and purposes, a swamp.  But, being above the treetops does afford me 360 degrees of horizon (except for a chimney).
73,
Jerry, K5OE
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