long wire

[thewrench002]

so i just ordered 100ft of 14awg unsulated 6 strand copper wire and two insulators to run down through the woods for my grundig750. i will be installing a G5RV in the spring along with a new tilt tower 50ft.... should i get a tuner for the G5RV or run it with out.... I mainly listen for EAM's and military chatter..

 

[ka3jjz]

A couple of things here - number one, no tuner will be needed with that antenna. You're not transmitting, so it's not nearly as needed.

One other thing is a question - which version of the G5RV will you be using? The 750 doesn't have the most robust of front ends, from all reports, and a full size G5RV might well overload the radio. This is particularly a problem if you live in an area with several high power MW stations nearby. I wouldn't at all be surprised if you needed to put a trap in to block the stations from overloading you, no matter what antenna you use.

Next, ignore what services you want to hear - antennas in general, and HF in particular, don't respond to services. Instead what frequency range do you want to go down to? Military chatter can be heard virtually anywhere in the non-broadcast HF spectrum (from the US and other countries). So something broadbanded would be needed. Certainly a G5RV (even the junior version) would do pretty well, but there are many other designs you can consider.

Finally I hope you've given some thought to properly grounding your installation. You'll be putting up a nice lightning rod there, and this is something that deserves serious thought

Mike

 

[Token]

For receive operation you do not need a tuner at all, for any antenna, let alone the G5RV.

That does not say there might not be some advantage to using a tuner. This is a discussion that comes up from time to time. There are some conditions when a tuner will improve a receive only antenna. Some older radios include an "antenna trim" adjustment that was sometimes basically a built in tuner. Some people swear you should use a tuner for receive operations, others say don't bother. I fall in the don't bother category, I have used tuner with receive operation in the past, but I find a well built and designed antenna just generally does not really benefit from such operation.

An antenna tuner is designed to present an acceptable impedance match to the radio in use. This is important for transmit operations as incorrect impedance results in reflected transmitter power coming back into the transmitter, potentially causing damage to the transmitter. A receiver does not have to worry about this, so that using any antenna and no tuner will not result in damage to the receiver due to antenna miss-match.

T!

(edit) Ooops, I see while I was typing KA3JJZ was also responding.

 

[thewrench002]

thanks for the response... i will be doing much research into this... i do have afew fm radio stations near me that over power my scanner antenna from time to time.... i was thinking on a trap for them as well.. i do have a good ground planed for it... MFJ 1778 G5RV Wire Antenna 160-10 Meters is my choice..

 

[ka3jjz]

At 102 foot, overloading the radio would be an issue. You could start hearing FM broadcast stations on HF (highly distorted) or broadcast stations inside the non-broadcast bands.

You may need to ride that RF gain control on the radio to keep this from being too much of a problem, but even so, there are other designs that are as broadbanded and smaller than this. An 80 foot Windom, for example, would be a reasonable match right down to 3 Mhz or so (it would work lower than that, but with less efficiency).

Mike