Re: QRO Operation Question

Don Wilhelm <w3fpr@...>


I would suggest that you equip each radio with a 2 position coax switch and a 100 watt dummy load.  Switch the radio to the dummy load when it is not being operated and to an antenna when it is used.  That is the fail-safe situation if only one radio is to be used at a time.

OTOH, you mentioned only two bands - 40 meters and 70cm.  If operation is confined to those two bands, they may co-exist just fine and even allow simultaneous operation if both transmitters are sufficiently clean.  If there are problems, a 30 MHz low pass filter in the HF antenna line(s) should cure it, and a High Pass Filter in the VHF/UHF antenna line(s) will even allow simultaneous operation with no problem.
If you have more than those two transmitters, a set of good bandpass filters for the HF bands would be in order.


On 5/27/2015 4:00 PM, kk5ib01@... [4sqrp] wrote:

We have a communications trailer with Arkansas Baptist Disaster Relief. We plan to run HF and VHF/UHF radios with antennas in close proximity. The trailer is 30 feet long and on the right front corner will be mounted a Comet GP-3 at about 15'. At the back corners will be two HF antennas, right back corner will be a screwdriver antenna at 10', and the back left corner will have a 25' push up pole with a 40 meter inverted vee, ends about 15' above ground. The UHF radio will be running 10 watts on 443.150, and the HF radio will be running 100 watts on 7.260. Should I turn the non-operating radio off when I am running the other one? Disconnect the antenna or just turn the radio off? Your suggestions appreciated.
Darryl, KK5IB

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