Legendary DX Commander introduces the new 7m telescopic pole. This is the small version of its big brother, the 10m DX Commander and delivers you just under 7m in height.
If you need a heavier pole, take a look at the 10m version.
- Length: circa 6.8m
- Max diameter of pole inc screw-over end cap 45mm
- Max diameter of lower tube: 36mm
- Lower diameter of second tube: 32mm
- Wall thickness: 1.3mm
The last section is solid fibreglass so that super-lightweight dipoles and doubles may be flown from the very top, albeit with some “curve”. This pole is not suitable for hard-drawn copper wire dipoles and doublets (for instance standard G5RVs) because that type wire is too heavy.
I have tested this with a 40m inverted V dipole using 1.2mm equipment hook-up wire with a spec of 7 x 0.2mm strands. I soldered the coax directly to the wire to cut any weight down at the feedpoint and used Aircell 5 coax (very light but similar spec to RG213) to good effect. But this pole will not accept a heavy head-load.
Verticals (Assumes insulated sheathed wire [velocity factor plays a part in the dimensions]:)
- 40m vertical. Go all the way up the pole with your wire, through the little loop at the top and back down again. Cut the length to tune for perfect match. Total length will be around 12m long. Next time I build this, I’ll give you the exact dimensions
- 30m Vertical. Cut your element length to 6.8m and fold back the end 6cms to form a loop. You’ll have a 10 MHz pure quarter-wave vertical and your ATU will easily tune 12m and 10m as a bonus.
- 20m. Leave off the two top sections. Cut your wire to 4.95m. Fold back 6cms. You will have a top-performing 20m mono-bander that will probably out-perform most of your other wire antennas on TX.
Ground Radials: Much baloney has been talked about ground radials. Do a google search, “how many ground mounted radials do I need” and you’ll find my paper. However, as a guide, 10% of the wavelength x 16 radials be only 1dB down on 64 radials at a quarter of a wavelength. I know what I do. Of course, being near the sea will also help, as will being up a darned great big hill.
Elevated Radials: If you want a no-tune version, you will need to tune your elevated radials just like you would do a dipole.
All-band: Use a tuner at the base of the antenna (for instance SG230). Use all the 7m of the pole. Add some radials and this will work from 160m through 10m.
Supporting your vertical: Find yourself a circa 35mm hoseclamp. Undo the clamp completely and slip over some 8mm / 10mm aquarium (which will protect your pole too) then do it back up. Make this into a guy-point by attaching three strands of paracord to this hoseclamp and then guy it out 120 degrees apart with some camping guy stakes. Fit the clamp directly ABOVE the last lower section. Of course, you can just bungee cord it to a gatepost / tree etc. Easy.
Delta Loop: I’ve never made a delta loop (yet) but I’ve modelled one and I can’t wait to build it. These 7m poles could make an excellent 20m project. Two poles would deliver a 20m mono-band rotatable delta loop with fine D10 wire or similar. Alternatively, use a tuner which will give you 30m through 10m performance. It’s on my list of projects actually and I have already bought some 20cm x 20cm half-inch aluminium plate. Just need to drill the holes out for some Stauff clamps. Watch this space!
That’s it folks. Have confidence. I have (currently!) a 100% feedback rating (on eBay). If you have any problems or concerns, address me directly. I always “do the right thing” and fix your issue. This is a hobby business for me with genuinely low margins. I use my own products for real on holidays and for personal experiments and your sale will help me buy more antenna gear, more analysers, more coax, make more aerials and keep paying the rent on my rather splendid hobby workshop! You’ll notice that I don’t have a catalogue of useless aerials that don’t work. I don’t sell 9:1 baluns or anything else that has excellent attenuation properties. All my designs and ideas are favoured towards those keen individuals that need all their RF energy going where they want, like into the ionosphere!
PS – There’s some review on eHam too and remember there’s a lifetime warranty on this, so if you break it what ever the reason, send me a pic of the broken one and I’ll ship you another one at cost.
Enjoy your radio!