[VHFcontesting] 500w SSPA's

[Terry Price]

Since there was such a large response, I will reply to the groups.

 

I’ve included a pix of the front and rear. This amp doesn’t have the
connector installed yet for the remote preamp and there will be a toggle
switch to select whether the remote preamp gets 12VDC or 24VDC.

 

The RF desk weights 30#, which means it’s get a decent sized heat sink. I
will test at full output on WSJT to see how hot it gets. It’s 3RU’s high
which is 5 ¼”, 17inches wide and has rack ears to mount in a standard 19”
rack. It’s about 18” deep.

 

The top LED will be a power LED denoting the amp is online.

The LED right below it will illuminate when the remote LNA is activated,
there will be a small toggle switch next to the LED to enable/disable the
LNA(If you get that option)

The remaining LED’s will be a bar graph display showing relative power
output – no calibration, just a quick way to see it’s putting out RF.

 

I have not tested the power supplies yet but they look like that are a
perfect match for the amps, 50V, 1kW output – 100~240VAC input. We will
install ferrites on the AC and DC lines for noise but ultimately, it’s up to
the end user to deal with any noise. These came from a low noise
installation so I suspect they are relatively quiet. We do not have enough
power supplies to cover all the RF decks so if you already have a 50v ps,
you won’t need another. The HP server supplies that are all over ebay are
fine for these amps also. 

 

We are going to offer these 3 ways:

 

1.       Basic amp with internal RF relays, W6PQL low pass filter, no
controller, no remote preamp support, no power supply, fans run all the time
(they aren’t noisy at all), 20w nominal input power for 500 watts output. -
$700

2.       Same as #1 but with W6PQL controller which gives remote preamp
support, temperature controlled fans, high temp cutout, front panel mounted
preamp on/off switch. - $900

3.       Same as #2 but we will include an integrated PAG103+ remote preamp
(.5 - .6 dB NF – not the best but a good start and VERY high quality relays)
in a weatherproof enclosure and 200’ of RG6 control cable with F connectors
on both ends to mate with the connector on the amp and preamp box. - $1200

 

If your exciter won’t put out at least 20w (like and old IC706, internal K3
transverter etc) an extra stage is available we can activate to lower the
drive requirements to a watt or so. We STRONGLY suggest adding an internal
attenuator to protect from overdrive. For the added gain stage and
attenuator it’s an extra $100 and you’ll need to tell us how much drive
you’ll have so we can size the attenuator properly.

 

The remote preamps will only operate when the power amp is on, this will
help protect the preamp since the sequencer will be active. If you forget to
plug in the PTT line from your transceiver/transverter and transmit into the
preamp, the “magic smoke” that makes all preamps work will escape and the
remote preamp will become a remote attenuator!!!

 

Each amp will be tested and leave in 100% working order, it’s up to you to
ensure you have an antenna connected BEFORE you transmit and that antenna
has a reasonable SWR (2:1 or less). It’s also recommended to start with low
drive to determine where your amp starts to saturate.

 

We will receive the amps next week and hope to have them all ready to go by
the 2nd week of July depending on parts availability.

 

Please reply direct if you want on the list for one and what configuration
you want. We ask for a 50% deposit next week if you are serious about
getting one. All prices do not include shipping. I do have good boxes and
packing so the amps will arrive in good condition.

 

Terry Price – W8ZN

Directive Systems and Engineering

www.directivesystems.com

703-754-3876

M-F 4:00 PM – 10:00 PM EDT

S-S 10:00 AM – 10:00 PM EDT