Recently, I was searching around for a new project when I realized that while I had Go Kits with 10 watts output and 25 watts output, I had nothing portable with a full 50 watts out. Never one to leave a project unfulfilled, I promptly ordered another Yaesu FT-7900R with the separation kit from HRO which at that moment seemed to have the best price. Since I wanted to have this larger kit have every possible capability except HF, that meant it had to be capable of being self powered (ie: batteries) as well as operating off of a gen set or mains power if that was available.
Thus the shopping list was born. Some of the items would come from stuff I already had in house, a few iterms would have to be purchased. Here is the list (with sources)
1. Radio: Yaesu FT-7900R from HRO in Atlanta approx. $270.00
2. Power supply: Mean Well 12.5 amp 12 vdc $27.08
3. External speaker: 1/2 of an old PC unpowered speaker set. free
4. Medium sized tool box (plastic) from Harbor Freight $8.00
5. Luggage carrier free
6. Coax cables assorted lengths 25' to 50' in hand free
7. Antenna (dual band, knock down to about 18" in hand free
8. 33 amp-hr SLA battery in battery box in hand free
9. Assorted wiring, switch and battery charger in hand free
10. Bungee cords to secure boxes to carrier in hand free
11. Hose clamps to secure antenna mast to carrier in hand free
12. Telescopic aluminum mast (extended 12 feet) in hand free
My total outlay therefore was $305.08 since I have a very well equipped junque box, actually more like a junque room plus a junque shed. Like many amateur operators I rarely throw anything permanently away. Even the dead transformer mentioned in the updates has become a handy hold down for soldering jobs.
Below are the pictures with captions that will walk you through the project.
One end of the radio box has been significantly changed since version one. The double power pole set on the left is now intended for providing power out to other devices as needed. The single powerpole set to the right of that is for input power from a battery or other source of 12 VDC. The socket labled power supply is for 110 VAC to power the included power supply and also has its own on/off switch just below the socket.
This project demonstrates the fact that no project remains unaltered for very long. In the space of about 3 weeks the Large Go-Kit went from having a large tote box and a very simple radio box to no tote box and a somewhat more complex system for thje radio box. Switches were installed and then replaced or removed as the modifications came about. This is not unusual for any amateur radio project. As we view the first attempt we realize that some aspects could be improved or a better method would improve the project.
So, naturally, I am still making minor changes to the radio box. I replaced the home-brewed separation cable with a more pleasing one made from a CAT-5 cable with the brown and brown and white wire pair removed leaving me a black 6 wire cable. I then installed RJ-12 connectors on both ends of the cable. I also shortened the cable to about 18". I then also shortened the audio cable of the external speaker in a major way thereby eliminating much of the excess cable that just cluttered up the interior of the radio box. It also got rid of the light grey flat cable which looked quite out of place. Pictures have been added or replaced in the article above to show the latest version
Another change that was made due to the elimination of the tote box was to create a hanger hook from 3/32" welding rod and hose clamp it to the antenna mast in such a way that the handle of the carrier can still be collapsed for transport in a vehicle. Since this photo was taken, barrel connectors have been added to one end of each cable run so that they can be combined if need be. The total run can be as long as 91 feet.
To the righgt is a view of the aluminum telescopic antenna with the base for the antenna semi-permanently mounted on the top section. From a collapsed length of approximately 3' 6" it extends to a hair over 12 feet. That should keep the RF well above the heads of the operators at least.
Here are the pictures of the new separation cable. The photo on the left shows the entire 15 foot cable. The other two photos show the male and female ends of the cable. All of the connections were correct and the cotrol head and speaker worked just as designed. (After a repair of a bad connection, at one end and a solder bridge that created a short circuit, that is). What can I say, that's why they call it amateur radio.
Because of medical issues that limit my stamina and movement, I have dismantled the large Go-Kit and added the FT-7900R to my home station. The telescopic mast has been sold along with the power supply. I am not getting out of amateur radio, far from it, but the realities of my more limited mobility are forcing me to take a more realistic view of my capabilities and opportunities.
This is actually version three of the large Go-Kit. The tote in version one that carried the battery and the coax and antenna has been eliminated. The antenna and coax are now hung or strapped to the vertical portion of the carrier. The wooden tray allows both the battery and the radio box to be secured by two bungee cords that can be used to secure the carrier with the antenna mast to any convenient picnic table or other secure footing.
The New and Larger Go-Kit
I had to use two photos to present the radio box. If I shot it in one go, the picture would be lacking in detail. On the Left side the control head, speaker and mic clip are secured to the box lid. The control head is connected to the main body via a home-brewed 6 conductor cable. This works fine and since the stock separation cable is much to long for this set up, the 1.5 footer works much better. Inside the box is the main body of the radio plus the power supply. One will notice that a 90 degree elbow is connected to the SO-239 on the back of the radio to make connecting the coax much easier. This picture shows version three. I am using a 12.5 amp supply which is quite slim allowing room for the extension cables. I also added a 3.5mm mono jack to the speaker front housing so that if a headset is needed, the headset plugs can be plugged into the mic jack and the speaker jack. I also created a pair of extension cords for the separation cable and the external speaker cable so that the control head can be placed on a desk or table and the main body with the power supply can stay on the floor under the table or desk. The extensions add about 6 feet of separation to the system. The picture above right shows the extension cables and the power cable which was supplied by a fellow ham Jerry Johnson, AE4XW
N1GY- The simple Approach to Ham Radio