[amsat-bb] Re: Questions on practical aspects of coax and preamps.

[Gordon JC Pearce MM3YEQ <gordonjcp@xxxxxxxx>]

Curt Nixon wrote:
> Good Morning All:
> 
> So, after this last week of ISS fun, I have the bug to upgrade into some 
> simple satellite work.  I will be confined to simple FM untill I can 
> upgrade to all-mode rigs.  My question is on coax and preamps.
> 
> I will use a pair of vertically polarized yagis to begin with.  One for 
> 144MHz and one on 70cm.  I have some LMR 400 I got for the ISS project 
> on 144 but it is so stiff, I didn't use it. 

I built a simple "Arrow-style" antenna using the WA5VJB Cheap Yagi 
designs.  One on 2m, one for 70cm, at right angles to each other, with 
an HB9ABX-design diplexer for the two.  I use this handheld with my 
Kenwood TH-F7E HT and get into AO-51, SO-50 and AO-27 without any real 
difficult.  Total time for construction about an hour ;-)

If you've got an antenna analyser or even just a good SWR meter, it will 
help a lot with getting the 2m part right.  I didn't bother tuning the 
diplexer much for 70cm because the MFJ-259 antenna analyser I was using 
didn't cover UHF - so I just woke up a 70cm repeater on the other side 
of town and tuned until I could hear it best.

I find it hard to get into AO-51 when it's busy and people are hammering 
it with huge stacked arrays of antennas.  When it's in QRP mode I get in 
no bother at all, with good reports from all over Europe.  Not bad for 
an aerial build out of a bit of scrap wood, some brazing rods and a few 
feet of hydraulic pipe ;-)

Gordon
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