[SixClub] Any one hear any Aurora yet?

[Roger (K8RI)]

On 8/5/2010 5:31 PM, doc at kd4e.com wrote:
> Excellent!  I wondered why I am not hearing this stuff
> here in EM92:  need 5 elements at 73 feet.
>    
It can be done with a 3L at 40 feet, or even a simple ground plane on 
stronger openings.
> And why I am not heard as well as some:  need 1KW!
>    
Not for CW and I worked many stations running 100 watts back in the 
early 2000s albeit I did have 7L @ 115' at the time.
With CW OTOH you will often find stations no stronger than the noise. 
They are just a change in the background noise. Most are running 
relatively slow in the 10 to 13 wpm range due to the distortion. I do 
think  a good 3L or larger Yagi would be the way to go for more reliable 
working of AU, but you really don't need a lot of power.

On strong openings SSB becomes difficult as the "aurora buzz" garbles 
them which can make then difficult to copy.
> Question1:  Do you use, or have you considered a receive
> pre-amp at the antenna?
>
>    
I do not.
> Question2:  What coax are you using, please?
>
>    
I was using Times Wire LMR-400 which is one of the least expensive RG-8 
size cables, yet it's also one of the lowest loss. It uses standard 
PL-259s or type N. I'd stay away from the UF versions (Ultra Flex) as 
they do not hold up well to UV and the elements, nor is the jacket 
abrasion resistant like the regular LMR-400, but it is the most flexible 
of the RG8 size cables I've seen.  Prices are in the 70 to 80 cents per 
foot range for the standard LMR-400. There are also several very good 
"knockoffs" of the cable, but generally you have to purchase quite a bit 
of it. Some is about half the price of LMR-400. Check The Wireman, 
RFParts, and Davis Electric. Another good as well as flexible cable is 
Davis BuryFlex which IIRC was around 89 cents per foot. It's a very 
flexible and TOUGH cable.

NOTE when I took the antennas and coax down this summer, the LMR-400UF 
pigtails that form a coil on the flat tower top plate had actually work 
through to expose the braid in a number of spots. Hence my reluctance to 
use the UF versions outdoors.

But for 50 MHz most RG-8 types will do fine. There is no need for N type 
connectors at this frequency and the loss even in UHF connectors at 50 
MHz is tiny. The loss figures you see for the connectors are for 300 
MHz.  With all the antenna switching, grounding at the top and bottom of 
the tower, patch panels...between the rig and antenna I have roughly 12 
connectors and the loss is barely measurable.
>> 6M band (since this is a 6 reflector), SSB. 5 element Directive
>> System yagi at 73' and 1 KW. The more gain and power the better for
>> AU (and most other propagation modes on 6M).
>>      
When the band opens you need little power, but directive helps a lot. A 
good 3L at 40 foot should do the job though as long as you aren't 
pointed at a large building that tall. OTOH as I said before, you can 
work aurora with a vertical on a good band opening.

My current system for six will be when finished, hopefully in a couple 
of weeks, a 7L C3i Yagi on a 29'8" boom at 115'. The pigtail/rotator 
loop is 28' of Davis BuryFlex that mates with a grounded bulkhead 
connector at the top of the tower.  Then 100' of LMR- 600 to the 
grounded bulkhead connector at the base of the tower. From there it goes 
into the switching enclosure at the base of the tower  where the 
"six-pack" is located for SO2R. From there it's also LMR-600 to the 
grounded patch panel/bulkhead and lightning arrestor at the building 
entrance (house and shop locations). From there I do have some LMR-400UF 
and 600 UF for patch cables and jumpers that I'm willing to use indoors, 
or in the underground conduit between the tower and the shop or house. 
The 600 is really too large for convenient patch cables even if it is 
flexible. Also connectors for the 600 tend to be  a tad pricey.  UHF 
connectors for the 600 are not pricey, they are ridiculous at $50 to $60 
each.

So for the den I have a 228' run of which 33' is either Davis 
BuryFlex(TM) and/or LMR flexible cables. For the shop it's about 190 to 
200 feet again with about 33' of the flexible cable.

The rig is an Icom 756 Pro (not II or III) running barefoot either SSB 
or CW at a max of 100 watts output. BTW I find aurora to be far easier 
on CW. I also have the Yaesu 897D, but it needs to go to the hospital 
and have its CW fixed.

73

Roger (K8RI)
>> Gary Mitchelson N3JPU Davidsonville, MD FM18
>> http://www.mitchelson.org/
>>      
>
>