repairs Needed

Below are repairs needed to K7UAZ equipment.

Status Updated 8-15-20


Troubleshoot and repair Remote Coax Switch Control Box (Ameritron) 8-7-20 This antenna switching system is defective, as determind by troubleshooting on 8-5-20. System symptom: measuring the SWR (from the coax connector that is normally connected to the HF transceiver) the SWR is unacceptable high in multiple antenna switch positions. The cause of the problem could be one or more of the following system elements:

a) coax switch controller

b) transmission line to the roof

c) Ccoax switch on roof

d) individual coax lines to individual antennas

e) individual antennas

To identify / narrow down the element that is defective the following procedure was employed:

(1) attached a 50-ohm dummy load to the coax that was attached to output of the coax control box in the shack;

(2) detached all coax cables from the coax switch on the roof;

(3) measured the SWR on the main transmission line from the roof switch position looking back towards the 50-ohm load -- MEASURED GOOD -- conclude the xmission line to the roof is GOOD;

(4) separately measured the SWR of all the antennas, FROM the coax end that was attached to the switch on the roof TO the various antennas (80-10m OCF, 40m dipole, 20m yagi, 15m yagi) -- MEASURED GOOD - conclude that all the antnnas are undamaged and nominally functioning (the 15m yagi is a bit high in SWR);

(5) Removed the coax switch controller and coax switch, put it on the test bench. Below are written notes from the bench testing. These data seem to indicate the control box is not putting out the proper voltages to effect relay switching in the switch box.

The coax switch controller and coax switch will be transported to Mark KD7PHW up in Phoenix for detailed troubleshooting and repair. Thank you, Mark!

--- other repairs ---

Kenwood TS-430s

8-15-20 This radio is no longer needed by the club and the club has decided to sell it.

a) The FM module should be removed, so the FM module can be sold separately.

b) The PTT light is constantly on, seeming to indicate a problem with the PTT circuit. While the PTT light is constantly on, the transmitter does not appear to be sending out RF al the time.

(unit transported to Mark KD7PHW in mid August)

Icom IC-207

8-15-20 This radio is desirable as a loaner to students.

a) Reports have been received on 146.52 that the transciever is signficantly off frequency.

(unit transported to Mark KD7PHW in mid August)

Icom IC-228H

8-15-20 This radio is desirable as a loaner to students.

a) The display normally is illuminated by one or two bulbs. Both appear to be burnt out.

(unit transported to Mark KD7PHW in mid August)

Yaesu Az/El Rotor Controller

8-15-20 We plan to modify the K7UAZ station to use an omnidirectional antenna, eliminating the need for this controller. Prior to selling this controller it is desirable to have it in working order.

a) One of the momentary switches does not return to the up position.

(unit transported to Mark KD7PHW in mid August)

Yaesu FT-212RH

8-15-20 This radio was donated to the club last summer, and we thought it could be used in the shack to monitor and talk over local repeaters. K7ZOO replaced the memory battery, but this repair seems to have failed. The user interface on this radio is not all that attractive. If the repair is easy, we might consider repairing it and selling it for about $40. Becuase of it's high visibility and possible use in the shack, it is recommended that we purchase a new 2m or 2m/70cm radio in the $200-$300 price range.

a) Memory of programmed channels is lost when powered down.

(unit transported to Mark KD7PHW in mid August)

Westcom RS-20A 12 VDC Power Supply

8-15-20 This power supply is useful to the club as a possible loaner to students.

a) When powered on, this power supply's back panel is very hot.

(unit transported to Mark KD7PHW in mid August)