Looking for a bit of assistance.
Ive modded my TS850 to allow LF/MF transmit from info from
http://we0h.us/Amateur_Radio_stuff/TS850/ts_850_lf_tx_mod.pdf
(thanks Mike, original by Bob ZL2CA) but the
"supplemental" parallel capacitor value in uF to increase the LF level
isnt mentioned.
Ive actually tried another 0.01 and smaller and higher values but at
137kHz it doesnt appear to increase the level - any takers or
experiences out there who have modded the beast?
We had a load of snow here at the weekend but thankfully its gone
already and Im in the garden pulling up new ropes into 2 Spruce trees -
a bit stronger than the bendy Birch and Ill attempt to pull up the loop
this week. The loop will be slightly bigger, about 50m in length and
slightly higher than WD2XDW in Bartlesville. We will see. COnditions
are lousy at LF and MF given the Geo/Mag at this latitude but I was
hearing Eu on 20m over the Pole pre dawn. We lose nearly 6 mins of sun
per day at this time of year....
Laurence KL1X
"The TS-850 transmit drive to the transverter port is
reasonably broadband as manufactured, and passes
some LF energy for amplification using an external LF
amplifier. It is difficult to modify the TS-850
circuitry to decrease the LF droop without impacting
on response at other HF bands. One modification
to improve low frequency response is to supplement
the value of C219 (a 0.01 uF capacitor, located
near L88). It is possible to solder a parallel
capacitor to the top side of the RF Unit PCB. Otherwise
the "broadband" circuits in the TS-850 transmit drive
are accepted for what they are. With C219
supplemented in value, 180 kHz output from IF OUT 1
is between about 100 and 250 millivolts,
whereas on HF it is more like 1 volt."
