Sam's Microwave Page


Loc: JO02PA

Web page established November 1997
Don't forget my blog, also established many years ago!

I'm back!


Picture courtesy of GM3SEK  Note, this is the V0.9 PCB, later updated to v1.0

GM3SEK, recently published a design for a low cost, 144MHz amateur band, masthead preamp construction article in the new RSGB
Radcom Plus
  digital-only, magazine available to RSGB members. Ian has asked me to stock the PCB and some other parts for the preamp.
PCBs, coil sets, Trituner tool, low noise MMIC, and Coax brass tags are available from G4DDK now
All other parts are available from Farnell or CPC and although they may need to be purchased in quantity, everyone needs some 1nF and 100nF SMD capacitors in their spares box!
A full Bill of Materials ( BOM), with ordering part numbers is included in the article.

Since publication Ian has updated his web page BOM to include some suitable alternative parts.

The total cost of the project should be a small fraction of the cost of a commercial low noise, high dynamic range, masthead preamp.

The DG8 is Relay switched and designed for single cable working. It can be Powered over the coax, or separately.
It is housed in a low cost, ABS plastic, weatherproof box available from CPC.

Short spec:
Noise figure < 1.3dB with gain adjustable from 11 to 18dB
It is powered from 12V supply and should use a sequencer, like all good preamps. See GM3SEK's web page or the DG8 article for suitable sequencers.
Best of all the masthead preamp is rated to carry at least 750W in  JT or similar 1 minute modes.

The short kit price is 19. Shipping is 3. I can accept Paypal. Please ask for price with Paypal. It will depend on whether you are in the UK or not. My e-mail details are in the graphic below.
If you are an RSGB Member, why not log onto the member's area and take a look at Radcom Plus? There is a lot more in there besides the preamp article and there will be more fine articles over the coming years.

Anglian 144MHz high performance transverter module

This is a high performance 144/28MHz transverter module featuring a ready-assembled PCB. There is now no SMD soldering required.
The kit comprises a tin plate box, connectors ( SMA) feed-through capacitors, tuneable coils, crystal ( 116MHz by Krystaly) and a few other parts needed to complete the build.
The PCB has been updated to the 'Gold' version. A number of small errors have been corrected. These are explained in the accompanying paperwork. Why 'Gold'? The new PCBs have gold plated pads!
A comprehensive PDF of the transverter assembly is here. Updated to V1.2 This covers a mod to improve transmit receive switching speed.
Kits are available at 125 each plus shipping. Kits now include the official Coilcraft TriTuner coil core and trimmer adjusting tool.

Anglian 144MHz 8W power amplifier
A 144MHz version of the 70MHz amplifier using the Mitsubishi RA08H1317M module is described in this article.
Short kits are available at 8. The Mitsubishi module is not included. Mitsubishi power modules are available from GH Engineering in the UK and from AngliaLive in Wisbech.

EME2014 Presentation added as PDF

Nacton 70MHz  high performance transverter module.
No longer available!
The Nacton 4m amateur band transverter module was awarded a 'Highly Recommended' at the 2013 RSGB  Centenary
Convention Construction Contest ( Designer category).
Among the judges were Joe Taylor, (K1JT) and Eben Upton ( Raspberry Pi Foundation).

Brief details of the Nacton are available here and more detailed information as well as construction and alignment details for the transverter here.

Several modifications have been made to the original Nacton following further work on the 2m version. These modifications are here
and now include the ones from the previous modifications document. Now version 0.2

The NACTON 4m power amplifier
A 7W Mitsubishi module type RA07H0608M available from GH Engineering in the UK.
PCBs for this module are available from the author. Suitable wire for the LPF as well as the passive components ( not the Mitsubishi module) can also be obtained from the author. E-mail to the address in the graphic at the bottom of the page for price and availability.
A full document detailing construction of the PA module is HERE

Short kits are still available at 8 each. Contact me for details.

Low Noise preamplifier (LNA) kits. Fully documented assembly.
for 70cm, 23cm, 21cm* ( Hydrogen line - radio astronomy), 13cm, 12cm, 9cm.

VLNA kits are available for all these bands. The price for a full kit is just 50. This includes the tinplate box, connectors and all components.
Complete and working VLNAs ( including for 21cm Hydrogen line) are available from The DX Shop
For orders over 100 I recommend International Signed For service, where available.
I can accept Paypal, cheque (UK bank only), or Bank Transfer.
A number of the kits are available fromWA5VJB
in the USA. Contact Kent at  Kent's web page for details of price and delivery.

E-mail me for Europe. My e-mail address is in the graphic near the foot of this page.
VLNA document. This has been updated to include a few small changes for the 70cm version.
Link to pre-amplifier articles Includes a 'must read' by Sergie, RW3BP


Have run out of THE ORIGINAL PGA Amp kits because of lack of PCBs. But, I have updated the kit to use the alternative PCB. The original  PGA Amp article is still here. 
The new version is called the PGA Amp v2 or PGAV2 for short.
The PGAV2 Amp features the facility for an output LPF or BPF as well as facilities to power the amplifier over the output coax feed.
The amplifier features the same low noise figure and high dynamic range as the version 1 (original) but on a marginally longer PCB. By changing some of the component the optimum performance can be moved up in frequency from VHF to UHF. Components for the filters are available separately. Currently these are 75 and 150MHz LPF and 70 and 144MHz BPF.
The basic PGAV2 kit is 13 + shipping. The filter kits are 1.50 or 2.0 for the LPF and BPF respectively.


A 144MHz high dynamic range, low noise preamp based on the earlier PGA Amps, but now incorporating an input high pass filter, band pass output filter, adjustable gain, on-board voltage regulator and provision for power feed over the the output coax. The preamp kit is supplied with tinplate box, long reach SMA female connectors and power feedthrough capacitor.
Short spec:
Noise figure 0.6dB
gain 2 to 20dB
Input two tone, third order intercept (IIP3) greater than +6dBm
Input return loss better than 9dB

The kit costs 35 plus shipping. I can accept Paypal. .
Contact me for details at the e-mail address at the bottom of this page

SPF Amps
With the popularity of the DG8 preamp I have seen demand for the SPFamplifier grow again, as it uses the same device. I have SOME PCBs with cable termination and some with SMA through hole SMA in Arlon material.
The original kit is available again, but in limited quantities, at 13. Ask for details if you are interested.

Micro X PCBs
Recently added. Micro X PCBs from WA5VJB. These boards accept MMICs and discrete devices in the popular Micro X package style e.g. ERA, MSA/MAR.
The boards are available in 'panels' of two at 5 pair. The material is 0.79mm FR4. Termination is cable, although a few SMA through hole boards are also available.

PCB Antennas
Kent Britain, WA5VJB's, wide range of PCB antennas have become virtual industry standards, widely copied at higher prices in Europe! These are the original and best PCB antennas, developed over a long period of time and used as OEM antennas by many commercial, monitoring and test houses in the USA and elsewhere.
I carry a wide range of these antennas, so if you see something in the list below that you want or on  Kent's web page  ask me first!


Log periodic yagis for 400MHz to 1000MHz, 850 to 6500MHz and 2 GHz to 11 GHz 
Vivaldis for 9 - 25 GHz, Big Wheels for 1296 and 2400MHz,
1.3GHz 3 element and 2.4GHz 5 element yagi antennas and 4 element patch antennas for 5.8GHz and more. Check Kent's web page for list.
Further details and prices by contacting the address in the graphic at the bottom of the page.

The UK Microwave Group
Tech stuff
WA5VJB Antennas

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Page first established November 1997