Station updates

I recently decided to make some equipment and antenna changes at station AB4D.

I had several transceivers and an amplifier that I had owned for many years, but were no longer used. Therefore, I decided to sell off some of that equipment.  A FT-1000D, a FT-840, and a Alpha 9500 amplifier were removed from service and sold.  The new owner of the FT-1000D was very pleased to obtain that transceiver, describing it as a treasure, and it certainly was in pristine condition.

Based on the sale, I planned to replace the Alpha 9500 amplifier with a manual amplifier. I was fortunate enough to find a used late model Alpha 8410 for sale at a great price. That amplifier uses a pair of 4CX-1000 transmit tubes. Eventually, I will replace those with a pair of 4CX-1500B metal tetrodes.  


A few years ago, I changed from using a microphone push to talk switch, to a dual channel foot switch for both transceiver and amplifier T/R switching control.  At first, I used a Heil FS-2 foot switch. However, after a year of use, it was beginning to show it's weakness, as operation became erratic. Another issue that always bothered me, was the weight of the FS-2.  The Heil foot switch is light weight made of stamped steel with a rubber pad.  During operating, I was constantly chasing the foot pedal, because it constantly crept under the desk.  To help remedy the situation, I changed to a commercial style foot switch that is used for industrial equipment control.  The new switch is a Linemaster Clipper 636S foot control pedal.  The Linemaster 636S is made of cast steel, offers dual adjustable internal switches, and weighs a sturdy 2.25 pounds. I find the Linemaster 636S foot pedal to be a significant improvement over the Heil FS-2.



I decided to try out a new inverted V antenna for the 75/80 meter band. I read many reviews, but the double bazooka design was one that seemed to have most of the positive comments. One model in particular, the antenna manufactured by IAC Antenna, had very good reviews.   I ordered one, and had the antenna in my possession in about a week. Construction appears to be very good. Unlike many of the antennas offered for sale that uses re-purposed plumbing pipes in their construction. The IAC antenna uses a molded UV protected plastic center insulated that encompasses the two radiating elements and the feed line connector.  The antenna uses Belden RG-58 and heavy 300 ohm twin lead in it's construction. I installed the antenna as an inverted V, center supported on a 72 foot tower.  On the air testing indicates that the DB antenna works comparable to a 160 meter full wave loop@35 feet off the ground.  In some cases the each antenna was either leading or lagging, at certain times depending on band conditions.  The major advantage of the DB antenna is the considerable bandwidth. Relying on the internal SWR meter within a Yaesu FTDX-9000MP, the 1.5:1 bandwidth of the DB antenna covers 3.700 to 4.000 MHz.

       
73 de AB4D