Discussion in 'Antennas, Feedlines, Towers & Rotors' started by WA6MHZ, Jan 4, 2012.
I found your replacement for the Town Car...
I could put that SMART CAR in my TRUNK!! LOL!
Meanwhile, the HAMSTICK Miseries continue!
Today I was on talking to Leif and Sue and the 3843 group while sitting in line for the Santee Swapmeet, and I noticed that the noise went up and down as the antenna was flexed. OH OH!!! I just fixed that!!!! I resoldered the bad antenna to wire contact joint!!!
After the swapmeet, I brought it into work and heated up the soldering gun very hot. HOWEVER, I found that no matter HOW HOT I got the joint, the WIRE would NOT Take Solder. Upon investigating it, I found it was ALUMINUM WIRE with a miniscule micron thick coating of copper which dissappears instantly when U try to solder it!!! RAT B*******DS!!!!!!!!! YOU CAN'T SOLDER ALUMINUM!!!!!!!!!!!!!!!!!!!
So what am I going to do now? Then I remembered what they do for Pigtails in old Mobile Homes with aluminum wiring. They use a CRIMP CONNECTOR to smoosh the aluminum wire onto the crimp and then to a copper wire to the outlet.
I drilled out the hole in the brass and retapped it for 4-40. Then I found a mini crimp connector with a tiny hole in the ring. The connector was CRIMPED onto the aluminum wire and then bolted to the brass shaft which goes to the base.
So, JETSTREAM uses CHEAP AND USELESS WIRE!!!!!!!!!! NO WONDER it is so cheap!!! Don't know how it will hold up, but it is back on the air now and flexing shows it still works (for now)
Good hearing you on the group this morning.
How much trouble is it to strip off the heat shrink and re wind the Hamstick with new copper wire and re-cover it??
Forums are trashed. U cannot create a new thread anywhere!
No, I can't rewind the coil. That would be an incredible undertaking. I would have to carefully count the EXACT # of turns, and how they are wound on the shaft, and then find the exact gauge of enameled wire to wind it with. Will see if this rinky dink fix works. So far it does.
I was wondering.
We missed you this morning.
It may depend upon how one defines resonance...
Some use the term "resonant" to mean where it presents 50 Ohms to the transmitter. That is not where it is resonant. At resonance, a 3.7 MHz antenna that is 8 feet long center loaded presents around 0.7 to 0.8 Ohms Radiation Resistance. (The power that is actually transmitted must be developed across this resistance.) In series with that is the Ground Loss, which will vary from between 6 and 8 Ohms (for a trailer hitch or bumper mount) to around 2 Ohms for a mount that is high up on a truck or SUV. In series with that is the Coil Resistance/Material resistance, which is pretty hefty for a small diameter small wire low-Q coil like the ones on Hamsticks and the "clones".
Everything except the Radiation Resistance is WASTED POWER. The key to a great mobile signal is to reduce all losses -- which means:
1. mount the antenna as high as possible to reduce Ground Loss
2. Use a Hi-Q coil to reduce coil losses
3. Match the TRUE input impedance of the mobile antenna by using a tuner like the Icom AH-4 at the base of the antenna.
NOTE: The so-called "internal tuners" really are not. They are really "line flatteners" that simply make the transmitter see 50 Ohms without fixing any issue at the antenna. They do not improve your actual radiated power.
On 20 through 10, the Hamsticks offer somewhat reasonable performance -- but certainly not equal to a Hustler or any of the large coil antennas.
I typically run my IC-7000 with the 20 Meter resonator. Because of the AH-4, I can operate 3.5 through 30 MHz (haven't tried 1.8), but there is a noticeable drop in transmitted signal on 7.x when compared to that achieved with the 40 Meter resonator. I cannot tell any difference when switching to the 15 Meter or 10 Meter resonators, so I no longer carry those with me.
I switch to the Hustler 40 Meter resonator if I intend local (to 500 miles) communication. I can actually operate 1.8 through 30 MHz with that configuration, thanks to the AH-4 -- HOWEVER, best efficiency is on 7.x and above.
True NO TUNE mobile operation is really nice. You can pick one or two coils (or coil taps) and operate on any band without having to get out and change anything -- and without having to have multiple antennas or resonators on the vehicle. Select the frequency, press PTT and start talking.
My son is WA6BEN! (and his name is Ben, so you know THAT was a Vanity call!)
I keep his license current hoping he will gain an interest in it someday.
Today we had a 17M Hamstick outperform a full sized multiband vertical at our Kids day site, so Hamsticks do work. Just not as well as we would like. Obviously, the best place for a good mobile antenna would be in the center of the roof, but we have to consider trees and parking garages. Thats why I have a big spring on my Hamstick.
Well in my case, could not get the Jetstream to work on 75/80m and later an analyzer confirmed high SWR in 3.5Mhz range and low SWR at 5.300. Think it was mislabeled at the factory and I don't have a receipt since it was cash buy at a hamfest. Oh well.
This is a good example of why I won't buy certain things at hamfests.