Hi Hugh
What instrumentation are you using ? dummy load
to match the amp and rf voltmeter could be a starting point ,
I don't think any of my bridges , work at 136 , apart from the
Rf probe + attenuators , 477 , the hf swr meter and bird
inserts [ with cal chart] work fine ..
No ferrites , I use air-cored inductors and a tapped one
as auto-transformer , things may get a little over
size at 136
Tx wise , PC with sound card as the audio source /
decode , the exciter is a Racal MA 1723 ,
will run to 136 , fine on 477 , that
feeds , via a stepped 10/1/0.1 dB attenuator to set the
drive , a resistive splitter and two skanti trp
8500 , 250 watt out ssb linear pa modules , which are
combined , with a [lucky-find] 5 port combiner , the
whole thing is wide band, the only tuner is
the ATU , variometer for 477 and a racal
1k auto tuner for HF , same Ae , can use it on HF,
but its a bit back to basic's ,
I use the audio drive on Opera , with the change
over hard keyed from the com-port , the racal set up is
getting on in life , but effective .. as long as it passes self-test
...
Psu is a ebay special , some sort of phone
exchange , switchmode 50 volts , not sure on the max amps , but
the plate asks for a 35 amp 240v supply , which by
the size of the copper busbar out put terminals , 150 A
is probably about right , but not from a 13 amp plug !,
the other is a old farnell variable 20 amp ..
Q What exciter do you use Hugh ?
73-Graham
G0NBD
Sent: Thursday, July 28, 2016 11:52 AM
Subject: Re: LF: From M0DSZ by M0DSZ Loc IO82LS 0.136 MHz (2200m),
OPERA, -36dB
Effectively linear amplifiers, class AB2, one 300W and one 500W
dc input with very low output impedance. The antenna current difference is less
than 5% so the expense of a new PSU, case and so on is so far wasted. Matching
for the 500W is awkward as the transformer primary for the 500W may need the odd
half-turn which is difficult with a toroid.
I can't send on Opera & WSPR
consecutively without some delay to reset the COM1 port.
Anyway I'm happy
to monitor both simultaneously by request or if there's anyone on. QRSS at the
same time is not yet possible because I only have COM 1 available and Spectrum
Lab doesn't like sharing. What's your setup?
Hugh, M0DSZ
On 27/07/2016 22:22, Graham wrote:
Just spotted you on the psk-map Hugh
There's a square law , to the current ,
doubling the power , gives a fractional increase ..
but still + 4 dB over the decoder limit , ~ + 9 over
the dynamic detector
What are you running, what's the set up ?
73-G,
Sent: Tuesday, July 26, 2016 11:27 AM
Subject: Re: LF: From M0DSZ by M0DSZ Loc IO82LS 0.136 MHz (2200m),
OPERA, -36dB
I'm pleased someone was monitoring, I suspect conditions were
not too good. This is a new linear amplifier but, in spite of having more
input power, doesn't produce much more antenna current.
Hugh,
M0DSZ
On 25/07/2016 19:48, Graham wrote:
One ping this afternoon
Rx
at Mon, 25 Jul 2016 16:17:22 GMTFrom M0DSZ by PA7EY Loc JO22JJFrequency:
0.136 MHz (2200m), OPERA, -36dBDistance:
530 km bearing 91°Using:
Opera v1.5.7/Rptr V1.6Antenna:
RX Op32
73,G
