[NLRS] HR-2510 vs HR-2600

[jcplatt1@mmm.com]

Here is one of the easiest ways to control output power.   Look at the
schematic .... locate the predriver stage that is one or two stages before
the final drivers (I don't have the schematic in front of me right now)
.... there is a 100 ohm fixed resistor between the NPN emitter and ground
where the drive to the next stage comes from.   Replace that 100 ohm fixed
resistor with a 100 ohm multiturn pot with the wiper connected to the next
stage.   You can then adjust the output power between 0.00 and 25 watts or
so with good control by adjusting the pot.   Use the normal SO239 connector
on the back so that you are still using all the 10m xmt side filtering.
For receive, locate the 39pF capacitor that comes off the xmt filters and
runs to the first RF gain stage .... lift it from the xmt filter side and
connect it to a BNC connector that you install on the back panel.   Use the
SO239 for 28 MHz xmt out and the BNC for 28 MHz rcv in.    The receiver is
plenty hot especially when you bypass the "lossy" xmt filters.   You can
poke around inside and find a control signal that goes to +9 vdc on xmt for
wiring to a NPN for PTT.

73, Jon
W0ZQ