Rattail Do or Do not?
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I remember those being advertised about 15 years ago, haven't heard anything about them since until today. My guess they don't help much if at all.
mmckenna
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Most antennas require a ground plane underneath them to work efficiently.
Hand held radios use the metal parts of the chassis as the ground plane. There is often some coupling to the human hand if it's being held, but that's not as efficient as having a true 1/4 wave ground plane under the antenna.
On UHF, 700MHz, 800MHz, etc. it's fairly easy to get the necessary ground plane. On UHF, 6 inches will do, 700MHz - 4 inches, 800MHz - 3 inches.
Low tier radios like the Baofengs often don't have much in the way of a metal chassis. So getting a proper ground plane is difficult. On VHF and lower frequencies, it's even more difficult.
Back in the days of big radios, like HT600's, etc. there was more 'meat' to work with. New smaller radios, not so much.
Installing a tiger tail or rat tail, or other counterpoise under the antenna can help a bit with reception as well as transmitting. A crimp lug sized correctly to go over the antenna jack on the radio with a 1/4 wave length piece of wire coming off it will help. You need to make sure the antenna is still making contact with the center pin, though.
So, for VHF use, 19 inches or longer will cover you down into the 2 meter amateur radio band. Longer is OK, but it needs to be at least 1/4 wavelength. No need to have a separate one for UHF.
You can give it a try, they are easy to make. I'd not expect any miracles, though.
When I am in RF challenged terrain I use a Diamond SRJ77CA antenna. I also have the SRH77CA and RH77CA versions for other radios. Additionally, I have counterpoise wires with properly fitting connectors for the radios as well. One or two are stored in the vehicle and others in gear bags. The counterpoise on a handheld really makes a difference in my field testing as well as sweeping with an analyzer.
The counterpoise for the 6m handheld is a bit much, but it works in a pinch.
The counterpoise for the 6m handheld is a bit much, but it works in a pinch.
I have rattails in my go box.. Was a lot easier with BNC's than it is with SMAs.. But I can attest, they do help in some situations. Like at the airport disaster drill (Simulated 737 crash with 75 souls on board) I get put in what could be the lowest area with my trusty T7A, couldn't hit the repeater until I put on the tail.. then if I emulated 70s TV antenna tuning (carbon dating myself here) I could get in no problems.
Rattails do work if you do them right and if you don't expect miracles. You are changing from a loaded short antenna who'z "groundplane" is basically the HT's metal body, to a vertical 1/2 wave dipole. If you can, swap out that rubberducky for a 1/4 wave to start with. That will make a difference all by it's self. Make that rattail the same length as the 1/4 wave antenna. As I said to start with, don't expect miracles, but there will be an improvement.
I have used and or tested various small diameter wires such as speaker wire and smaller, alligator clips with thin wire, etc. They work fine on the radios and swept well on a VNA trying various antennas during testing. The most important part is to use a proper antenna. A four inch stubby antenna with a counterpoise (rat tail) will not work as well as say a 16" stubby on a handheld, with or without a counterpoise. (Now I am wondering why people started calling a counterpoise a rat or tiger tail.)
I never tested using coax, nor large unwieldily wire like #10 etc. for use with a handheld. I do not have any plans to do so.
Again, I never use them until the signal is poor for either TX or RX. They do help and are worth the effort to take a bit of spare wire and cut it to length. Still, I carry very long telescoping antennas in my bag as well. One for six meters and one for two. Although I would not walk around with them attached, they get the job done for making a quick contact, or if sitting in a fixed position.
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mmckenna
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Just plain old wire. Get some 18 gauge stranded wire and you'll be good.
Thanks for the reply and information. I really appreciate it. I understand the need for using a better antenna to begin with. Upgrade from a 4in or 6in stubby is usually the first order of business if I am having difficulty with TX or RX signals.
I would only be guessing but I could see this counterpoise design getting the nickname "Rat Tail" because of the way it looks on a handheld radio.
Thanks for the info, I am excited to try it out. What would a guy do if he has a handheld radio that doesn't have a center pin style antenna. For example a Motorola HT1250 or a Bendix King DPH?
mmckenna
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Find a screw on the back of the radio that is connected into the radio chassis that you can connect to. On the Motorola, try the screw where the speaker/mic attaches.
Another way of connecting a 'tail' is to unscrew the antenna slightly and expose the threads. Wrap the wire around that threaded portion and tighten the antenna back down. As long as the wire makes contact with those threads it's connected. It only requires maybe one wrap, not several. Otherwise the antenna will never screw back down, right?
mmckenna
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Yep, but not on the MX series antennas used on some of the Motorola gear as well as non-coaxial connectors used on some older radios. Those are simply a stud that screws in to the top of the radio. The entire thing is part of the radiating element. You don't want to wrap wire around that, it'll detune the antenna.
I have very seldom ever used Motorola HTs and added a rattail to it. The one's I've used were not mine. I don't mess with my employer's equipment without specific instructions. If I had asked, I can tell you what the answer would have been, so why bother??
Indeed.
Additionally, a Moto APX 7000 and the like has a deep well, so wrapping a bit of wire around the base will not work. Fortunately, as mmckeena pointed out, the screw point at the side would be the ideal point of attachment. One could easily slip a thin ring terminal on there with the wire attached. Plus, the screw is metal to take care of the continuity to the chassis.
I am not familiar with BK radios. A quick look at that model did not provide a definitive answer. I am unsure if the screw point has continuity to the chassis and if the screw itself for the dustcover/mic is plastic, nylon, or metal.
I do not recommend using a rat tail wire on a handheld radio. Otherwise you might end up with a radio that transmits and receives further.
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