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DX Engineering HotRodz Capacity Hats

 
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n0hr
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Joined: 05 Feb 2007
Posts: 93
Location: Iowa

PostPosted: Sun Apr 01, 2007 2:33 am    Post subject: DX Engineering HotRodz Capacity Hats Reply with quote

I've had these capacity hats installed for a few weeks now. It does seem to improve a HF mobile antenna system. In my case, I'm using the High Sierra Sidekick with the Hot Rodz and DX Engineering MM-1 Un-Un. As a system, so far so good.

Anyone else tried this combo?
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AC0HD
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Joined: 17 Aug 2007
Posts: 7
Location: North Central Missouri

PostPosted: Sat Aug 18, 2007 1:19 pm    Post subject: HotRodz Reply with quote

I put the HotRodz setup on my mobile Hustler 15 Meter resonator out of "necessity" so I could tune 20 meters a few months ago when I was putting my mobile rig together. Hustler had backordered the 20 meter resonator and 20 is where I park a good portion of the time.

I like the top hat setup. I think it may even be a little more effective. Maybe not a GREAT deal better and possibly even just psychological but I seem to make more successful contacts during high noise and pile-ups on 20 meters using the 15 meter resonator with the HotRodz than with the standard 20 Meter resonator...

I also bought the optional extra long rods to use to tune in 160 using my 80M resonator. It works but the bandwidth is EXTREMELY narrow and the 54" mast on the receiver hitch won't put it high enough over ground to get a very low swr. For most effectiveness I either add 2 - 54" masts together or at minimum use a 72" mast. With the extreme diameter of the 160 Meter tophat radials and the necessary extra height on the flimsy (for the added weight at speed on the highway)masts, this limits me to stationary positioning of my vehicle when using 160 meters but o more than I talk on 160, this is fine...it is rag-chewing anyway and carrying on a rag-chew while driving in traffic probably isn't the safest anyway....just notice how many dangerous vehicles on the highway have cellular conversationalists at the helm next time you come up on one running 45 in the passing lane or driving like a zombie.

For the added height I also picked up one of Dx Engineering's 72" masts which I like but wish was just a bit more rigid. I have a quad resonator (quad band) setup usually attached and it is fairly heavy so I have guy lined it (receiver hitch mount aback my Cherokee Jeep with suction cup hooks on the roof to tie nylon guys to) but the stock 54" mast is more stable with the weight even guyed than the more flexible 72" DX Engineering mast. Soooo I use the tall mast for mono band ops and the shorter more rigid 54" mast when guyed and using the quad band setup.

I am sold on the Hot Rodz capacitive topHat setup...

Also I've found that SWR can be varied by moving the radial setup up and down the resonators stinger tube altho instructions say to put it at the top as close to the base of the stinger as possible. Supposedl according to my 'mobileering' book, any portion of the antenna above the topHat radials is largely ineffictive, anyway but it WILL vary the tuned freq a bit it you're close and don't want to trim the stinger or radials by moving the hat up or down on the antenna shaft.

Les - ac0hd
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AC0HD
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Joined: 17 Aug 2007
Posts: 7
Location: North Central Missouri

PostPosted: Sun Feb 10, 2008 5:28 am    Post subject: Works on other antenna setup also. Reply with quote

In my quest to expand my mobileering band experience, I ordered a PHF-160 antenna which I added to the top of the Hustler quad-band setup previously mentioned. It is pretty tall to be sitting atop the 54" mast which is on my Jeep, so I went to work to find a workable resolution to the extreme height of the full 160M antenna atop the 54" mast.

To make a long story short, I ended up making my own custom length radials for the DX HotRodz system to use with the 160M PHF-160 antenna. Each radial is cut to a bit over 13" in length giving a mounted radial length of about 12.5". With 6 radials extended the antenna is tuned to 1.8 Mhz without a stinger and when shortened (by sliding in) to a little over 8" each, the antenna is tuned to 2.0 Mhz without a stinger. SWR at resonant freq is less than 1.5:1, though as expected for a mobile version of a 160M antenna, the bandwidth is pretty narrow but usually there isn't a lot of moving around on 160... even if you do is just a matter of a minute or two of adjusting the radial lengths to the frequency of choice...with just over 3" of radial length adjustment to take it from 1.8 to 2.0, with a little practice you can either mark a common freq's resonant setting on each radial for a preset mark or at least get it in the ball park pretty quickly.

Still tickled with the Hot Rodz performance and versitility/

73,
Les - ac0hd
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