Usually some form of high density polyethylene (HDPE) or a variety called UHMW - ultra high molecular weight which is quite slippery and used as an inexpensive substitute for TFE in sliding bearings,
I have the same question with a bit of a twist - the 2.4" cores cost about $6 each @ Arrow, and make a lot of sense in a QRO transmit application. But, that is a lot of ferrite for a receive antenna
Browning is another choice for sprockets. Why not use a timing (synchronous) belt instead? It won't rust and can be sized for any load you might need. http://www.emerson-ept.com/eptroot/public/prod/d
One other input - many larger pulleys/sprockets/timing drives are made with shaft adapters so one sprocket/gear/pulley size can fit many shaft diameters. Check the catalogs for this style of "sprocke
Goop up the first 10' very heavily. Then a couple of ounces slathered on every 15' are more than enough. The person feeding can do it as the cables go in the conduit. Wear nitrile gloves or the half
Re your original question - having both the DG8SAQ VNWA (sdr-kits.net) and original AIM4170 here are some of my thoughts - Of course the VNWA can do much more as a two port VNA, has an attractive pri
The W6NL 40M Moxon has several design iterations. As far as I know there are 4 versions, in time sequence I think they are V1 - 2006 original Cushcraft modified XM-240 V2 - 2007 center of element str
re items 1. your concrete supply house should have plastic inverted basket supports in different heights for rebar . These are used instead of the concrete blocks with the wire tie imbedded in them,
For a wood telephone pole mounted A4S I built a similar, but longer, cage ala W8WWV. I made it about 3.5' long from rotator shelf to thrust bearing as to reduce the moment on the rotator (the antenna
316 stainless is a good choice for corrosive environments. Some sailboat makers use it for rigging and good boatyards may stock it and certainly will have swaging equipment and fittings if you can ge
I found the MFJ's useless at a prior QTH which had a 1 MHz BC 50kw line of sight 2 miles away. The MFJ detector is energy based and not very frequency selective so most any nearby transmitter can cau
I'll second the motion that the DX Eng saddle clamps are the way to go. Lots of surface area of the saddle in contact with the mast and stainless u-bolts are provided. Use a SS nylock nut backing up
No doubt one can design and spend $$$ for boom clamps that will exceed the torsional strength of the mast, but why bother when off the shelf economical hardware will do the job? The major problem we
Common Loctite cures in the presence of iron (Fe) and the lack of Oxygen (O2). Interestingly, those plastic Loctite containers are oxygen permeable so it doesn't cure in the tube. So a tightly enclos
And you can also get flooded CAT 5. A little messy to terminate with the goo (silicone?), some is stranded, and tough and/or UV resistant jacket for direct burial or aerial use. Lots of it on ebay. h
RG304 but get out your wallet, if you can find it! 0.28" od http://www.awcwire.com/Part.aspx?partname=RG304 Also RG142 dbl silver braid is close to QRO all bands, same as RG303. 1900 volt max. Grant
I think the steppIR specs relate to the antenna wind survival and sq ft does not change with wind speed. Wind load is proportional the the square of the velocity, so a new L470 rated 85mph/18 sq ft s
I've had great results with Rust-Oleum Direct to Metal (oil) alkyd enamel paint (Grainger stock item, others as well). I use two coats of primer, red first, then grey to prove coverage, followed by t
I've had excellent results with a metal roof as the ground plane for a two different single band verticals on two different structures. You have a real asset if it is of decent size - 1000 sq ft +. C