Re: LF: Re: FT-817 at LF/MF

[Dexter McIntyre W4DEX <dmcintyre@att.net>]

Roger Lapthorn wrote:

> On 137 kHz the FT817 RX is unusable and I've been trying with a simple 
> SBL1 up-converter with some post mixer gain......
Roger,

I have a FT817 I bought used a few years ago.  I got a real deal on it because 
it had no output power.  I bypassed the dead FETs and got +10 dbm out on 144 mc 
which is exactly what I wanted for a microwave IF.  I have used it for 500 and 
137 kc receiving.  Works great with no help on 500 kc but is a bit weak on 137 
kc unless it's connected to a big antenna.  On my transmit antenna it needs no 
help but for best receiving I use an amplified balanced loop.  With that antenna 
the FT817 works as good as any receiver I've used for QRSS reception.
Below is the receive sensitivity I measured to produce a decent audible CW 
signal:

100 khz   1000 uv
125 khz   5 uv
150 khz   3 uv
175 khz   1.5 uv
200 khz   1 uv
250 khz   0.5 uv
300 khz   0.2 uv
350 khz   0.1 uv
400 khz    <0.1 uv
500 khz    <0.1 uv

Dex