Product information

Anglian 3 Transverter - News

Sales of the Anglian 3 are currently temporarily on hold. See below for details.

At my request Leif, SM5BSZ, has conducted a range of measurements on the Anglian 3 transverter. As a result of his measurements an upgrade to the Anglian 3 is currently being tested. Leif's results so far indicate a significant performance improvement.
Whilst the Anglian 3 largely performed as measured. Leif had some concerns about amplitude noise (AN). This is not something you will see quoted for many amateur radio rigs or transverters. More commonly designers and reviewers concentrate on phase noise (PN) and the effects of this on receiver reciprocal mixing and its limitations on dynamic range. Also the contribuition of phase noise to overall transmitted 'broadband' noise or 'composite' noise.  AN noise is equally as important but often ignored.
The best current HF transceivers have a reasonable AN noise performance, but it is not exceptional with one or two exceptions. Driving an Anglian 2 or 3 with one of these (many) HF rigs, the HF rig's AN and PN noise will dominate the transmission (together with IMD), but with a contribution from the Anglian. Leif was able to determine the source of the greatest noise from the Anglian and in testing found he was able to make a significant improvement in the Anglian's AN and PN noise, such that all but the very best HF rigs will now become the dominant source of transmitted noise.
I have started to test the changes in my own workshop and if both successful and economically viable I will release the Anglian 3L with the improvements and also offer parts to upgrade existing Anglian transverters (where possible). Please bear with me as I introduce the upgrades.


VLNA

VLNA is now synonamous with the G4DDK low noise preamplifier for 23cm and 13cm. Versions are also available for 70cm and 9cm. It stands for Very Low Noise Amplifier. The name is not unique, but has become synonamous with the G4DDK preamp.
The VLNA has been remarkably successful since it's introduction  over lunch, at the 2007 Weinheim VHF meeting in Germany! The current serial number is now over 2200.  This does not mean that is the number sold, but it's not far off!

When developing the VLNA for 23cm EME experience was drawn from the design of WA5AGO and work by WA5LUA (now W5LUA). My contribition was to realise that the ATF54143 would make a far better, low noise, higher dynamic range second stage than existing designs.
The original VLNA was meant for 23cm only. The noise matching was optimised for 1296MHz operation. It wasn't long before I discovered that the design could be stretched to 2320MHz and later to 3400MHz and 432MHz. All from one PCB design.
After a board redesign the Issue 2 board has been in constant production for about 9 years.
It would be unfair not to recognise the contribution by RW3BP. Sergie did some further work on the VLNA and improved its input match, lowered the noise figure and improved its stability. However, not all of Sergie's ideas are practical from a production point of view and so the VLNA has adopted some of his ideas including use of the MGF4919 as the first stage. In practice this has provided a lower noise figure than the previous NE32584 (most of the time) and a noise figure of around 0.25dB is now typical. Previously it was time consuming, but possible, to get below 0.30dB and occasionally to 0.25 and even down to 0.22dB. Now, these numbers are open to debate in view of the difficulties of accuracy and repeateably measuring such low noise figures with any great meaning. However after many hundreds of measurements in Europe, and North America, it can be claimed that 0.25dB is achievable and on-air results in EME operation have confirmed the extremely low noise figures achieved by builders of the VLNA.

VLNA9 uses a different input device in order to achieve a noise figure of below 0.4dB.

A word of caution. The VLNA23 has a very high gain of around 37dB at 1296MHz, with the absolute gain peak of around 40dB occuring at about 1.05GHz. This is intentional and a result of the low noise input arrangement. It is quite normal in low noise designs. But, it does mean that you need to be careful when using the VLNA23 not to pick up nearby 900MHz Mobile Base stations as the amplified output from the VLNA may cause gain compression (blocking) in the later stages of the receive chain. The gain of the VLNA13 and 9 are a bit lower, by about 10dB, so don't tend to suffer this problem. The gain of the VLNA70 is deliberately tailored to be no more than about 34dB in order to reduce blocking from nearby digital TV transmitters. You should carefully consider whether you need the full gain of the VLNA23 when attempting to use it with terrestrial systems and it is recommended that a 15-20dB pad should be inserted after the VLNA23 and before the following receiver. This may also be necessary with the VLNA70.

So, now you are familiar with the number one  23 and 13cm low noise preamplifier, go to the price list and see if you would like to buy one from me. You can choose the band, kit or board-assembled, and how you want to pay. I don't have an on-line shop so you will need to  e-mail  me  to ask about availability. e-mail at the bottom of the page.  I accept either Paypal (prefered) or bank transfer. In the case of bank transfer I will need to send you an invoice first.
For Paypal I will ask for your callsign (if appropriate) and shipping address to be added in the Paypal payments comments box. This is for my reference, even if you have already given me these details.


vlnapcb

Note, this is the old, original, PCB from 2007

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SPF Amplifier

These amplifier kits are based on the popular boards by WA5VJB.
The SPF Amplifier components are optimised for the frequency range 400 to 2400MHz
Board kits are available for SMA input and output as shown below. These boards have no provision for extra RF path filtering
The smaller cable terminated boards are in extremely short supply at present.
The SPF Amplifier performance is shown in the SPF Amp PDF

SPFAMPPCBs



 PGA wideband amplifiers


If you want high dynamic range, low noise and widebandwidth, then the PGA Amp is the one to choose. Currently PCB levels are very good.

PGA Amp PCB

PGA Amp PCB This board is also available ready assembled, to order.

The PGA Amplifier kit provides a noise figure of below 0.5dB at 2m and 70cm, rising to 0.8dB at 23cm. However, the wideband frequency response of the PGA Amplifier means that it is important to use a filter either at the input or output of the amplifier IF IT IS CONNECTED TO AN ANTENNA. This makes the wideband PGA amplifier better suited to use within equipment to boost levels, reduce noise figure or just add gain. Full details of performance are published in the PDF
The PGA144 (described next) is a truly Contest grade 2m preamplifier and already incorporates the necessary filtering.

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PGA144

This is a fully filtered, low noise, high dynamic range contest grade preamplifier. Unlike other PGA based amplifiers the main filtering is at the input, with a broader band pass filter at the output. Two metre receivers are prone to blocking from nearby Band 2FM broadcast transmitters in the 87.5 to 108MHz frequency range. Whilst the FM transmitter will be unlikely to trouble the PGA144, the following receiver may become 'blocked' by high level Band 2 signals. Blocking or gain compression manifests itself as a reduction in sensitivity and can even produce intermodulation artifacts on top of wanted signals. The 130MHz high pass filter and notch arrangement used in the PGA144 was devised by G4SWX as a combined Band 2 notch and 2m bandpass filter that reduces the Band 2 signals to 'safe' levels whilst introducing minimal input loss at 2m. Hence the low noise figure of the PGA device is maintained. The PGA144 is suitable for EME where the very low noise figures often quoted for some designs cannot be used in practice due to high local noise levels, but where 0.5-0.6dB is more than adequate and the PGA144 very high dynamic range allows operation where some other low noise, low dynamic range, preampliers can be a problem.

PGA144 Picture

The PGA144 has built in gain adjustment, supply regulator, provision for over-coax powering and SMA input and output connectors.
Please note, the PGA144 does not incorporate any antenna switching relays. You need to provide these yourself!

PGA432


Following on from the successful PGA144 preamplifier the PGA432 uses the same PCB circuit techniques to deliver a low noise, high dynamic range preamplifier for the 70cm band. A deep notch at 144MHz is incorporated as protection against strong 144MHz (2m amateur band) signals such as might be experienced when operating on 70cm during a multiband contest or when using satellite Mode J with the user uplink on 144MHz. The notch is over 60dB down on the wanted 432/435MHz at the preamplifier output.




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