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G4DDK / W5DDK
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VLNA70 PDF 1B
As published in DUBUS 3/11. The new VLNA70 is the result of a lot of work to produce a stable, repeatable 70cm low noise preamplifier using the PCB and mechanical arrangements of the well-known 23, 13 and 9cm VLNA2+ preamplifiers. The VLNA70 provides a noise figure of better than 0.4dB with a gain of 40dB. The input P1dB point is approximately -20dBm. The input return loss is approximately 10dB. With careful adjustment the input return loss can be improved to 20dB or better. Best of all, the new VLNA70 is stable in operation. It is impossible to guarantee that it is stable at all mismatch phase angles, but tests suggest that it will remain stable with most if not all current 70cm antenn designs. With 40dB gain second stage noise contribution should no longer be a problem in EME systems. For terrestrial use I recommend a 20dB attenuator at the preamplifier output. The PDF includes construction details. However, it is best to read this in conjunction with the following VLNA2+ PDF C2
In order to simplify names the VLNA preamplifiers are now all called VLNA, with the VLNA70, VLNA23, VLNA13 and VLNA9 covering the 70, 23, 13 and 9cm bands respectively.
VLNA PDF C2
This document now replaces the previous PDF. It incorporates all of the VLNA2+ updates for the 23, 13 and 9cm versions of the VLNA2+
The original Issue B3 is still available here for those who need it.
VLNA kits are £49.50 each plus postage and packaging. For orders over £100 I recommend International Signed For service, where available.
All band kits are the same price plus postage and packaging.
I
can
also
offer
the
VLNA2+
kits
with
male,
4
hole,
connectors for the same price.
For payment, I can accept Paypal, cheque (UK bank only), or Bank Transfer.
For payment, I can accept Paypal, cheque (UK bank only), or Bank Transfer.
E-mail me for details. My e-mail address is near the foot of this page.
Link to pre-amplifier articles Includes a 'must read' by Sergie, RW3BP
SPF5043Z amplifier. The SPF5043Z amplifier article appeared in the July 2011 issue of Scatterpoint, the newsletter of the UK Microwave Group. This is a slightly updated version of that amplifier article. It includes some new figures and details of the kits that are available from me. For readers in the USA, similar kits are available from WA5VJB.
News update
The new PCBs have arrived.
See here for details of the types of PCB available for this kit.
Cable termination PCB SPFAMP
G4DDK2001 Source
PCBs and filters for 1152 and 1296MHz are still available.
Contact the e-mail address in the graphic at the bottom of this page for further details and prices.
Thanks to the RSGB for allowing me to publish a reprint of the original G4DDK2001 Radcom Article on my web page.
WA5VJB PCB antennas
Stock is constantly changing. Please inquire for current stock position.
1296 MHz and 2.4GHz 'Big Wheel' antennas and 1.3GHz yagi antennas
Further details and prices by contacting the address in the graphic at the bottom of the page.
| Contents The UK Microwave Group RSGB Tech stuff WA5VJB Antennas About G4DDK Links G4DDK Blog Spot Change history:- 07/03/2012 SPFAMP Update some other general updates. 13/3/12 SPFAMP PCB information |
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given
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| 07/03/2012 |
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first
established
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1997
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