[TowerTalk] Field Day

Grant Saviers grants2 at pacbell.net
Mon Jul 3 09:52:42 EDT 2017

We (N7KE) haven't had the lack of interference others note re same band 
operation on FD.  So am looking for ideas about what to chase or improve.

Operating 2A on two separate generators - Honda inverter 1000EU, no 
interconnections of stations
Stations inside travel trailers, about 175' apart
two A4S beams at 42',  elements end to end and separated by about 225'
two 80/40 fan dipoles at 65' parallel and separated by about 450'
SWR on all antennas is very good, antennas tuned to the band segments
Correct chokes on all feedlines at antennas, no RF at the rigs
no more space to get the antennas further apart
SSB with K3 and CW on IC7300 (7300 RF gain set w/o overload of A/D)

We experience lot's of buzz from cw into ssb, need to get as far up the 
band as possible.  Reverse also true.  About the same level of trouble 
as last year with the beams 75' closer together.

Tried a new vertical 40m dipole this year on ssb and noticed less 
problems, which was expected with the crossed polarization.

As an aside, what do others do for grounding on FD?  We have about zero 
lightning here.

Any designs for 100w same band filters appreciated.

Grant KZ1W

On 6/30/2017 10:44 AM, Huff David J wrote:
> One other point to make that has not been stressed.  Field Day rules allow up to 1000 foot diameter for all operations. (984 feet to be exact. They specify 300 meters or 1000 feet diameter)
> That means if you use good coax and tuned antennas, you can spread the antennas over a wide distance.  Putting the antennas on the same tower or pole is likely to cause interference.
> Generally the rule of thumb is coax will have higher losses if the SWR mismatch is bad, but you can use a very long run of coax to separate your antennas.
> Many field days also spread out power and grounds, so that noise on one is not radiated to the other, and battery operation is a really good way to isolate DC power from each other.
> Thanks,
> David
> W0IM
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