LAMCO AT-5189 4m

Here is an interesting radio for sale at LAM Communications in the UK, it is a 45w FM radio for the 4m band.

I have placed my order and should have delivery of it in the new year.
I will do a review of it when I get it.

Here are the specs:

Output Power:45W/25W/10W
250 channels, every channel can be named with 32 characters
Can be divided to 10 scan groups.
One priority scan channel for each group
CTCSS/DCS/5-Tone decodes and encodes
ANI function (display missed calls)
Single call, group call, selective call are features
Emerqency call are all available

Accessories:

Microphone
Mounting bracket
DC power cable with fuse holder
Hardware kits for bracket

Technical Specification:
Frequency Range: 66-88MHz
Channel: 250 Channels
Channel Spacing: 25kHz(Wide Band) 20 kHz(Middle Band) 12.5K (Narrow band)
Phase-locked Step: 5kHz 6.25kHzOperating Voltage: 13.8V DC 15%
Squelch: Carrier/CTCSS/DCS/5Tone/2Tone/DTMF
Frequency Stability: 2.5ppm
Temperature Range: 20~+60 4 F~+140 F
Dimension (WxHxD): 160 x155x 40mm
Weight: 1Kg
Receiver (ETSI EN 300 086 standard testing )
Sensitivity (12dB Sinad): Wide band 0.2V Narrow band: 0.25V
Adjacent Channel Selectivity: 70dB 60dB
Intermodulation: 65dB 60dB
Spurious Rejection: 70dB 70dB

Audio Response: +1~-3dB(0.3~3kHz) +1~-3dB(0.3~2.55kHz)
Hum & Noise: 45dB 40dB
Audio distortion: 5%
Audio power output: 2W@10%
Transmitter (ETSI EN 300 086 standard testing )
Power Output: Wide band: 45W/25W/10W(VHF) Narrow band: 45W/25W/10W
Modulation Wide band: 16K F3E Narrow band: 11K F3E
Adjacent Channel Power: Wide band: 70dB Narrow band: 60dB
Hum & Noise: Wide band: 40dB Narrow band: 36dB
Spurious Emission: Wide band: 60dB Narrow band: 60dB
Audio Response: Wide band: +1~-3dB(0.3~3kHz) Narrow band: +1~-3dB(0.3~2.55kHz)
+1~-3dB(0.3~3kHz)
Audio Distortion: 5%

Price and shipping can be found at the following link.
http://www.lamcommunications.net/shop/product_info.php?products_id=621

Slim Jim Antenna for the 4m Band.

This 4m Slim Jim is cheap and easy to build yet it greatly out performs the more usual dipole due to its low angle of radiation. An SWR of 1:1 is obtainable across the 4m FM band with simple adjustment. The photograph and PDF diagram show the construction, however a brief description is also given. The spreaders are made from plastic knitting needles; two small holes are drilled about 10mm in from each end of the spreader to accommodate the aerial wire. Suitable sized holes are then drilled in the fishing pole to mount the spreaders. The spreaders are then glued in position using a two part epoxy. The telescopic fishing pole sections are also glued to each other using epoxy. Once the glue is set the antenna wire is then threaded through the spreaders according to the diagram. RG-58 is connected to the matching section but not soldered yet, just wrap the braid and inner around the aerial wire. Raise the antenna at least 3m above ground and clear of any objects (walls etc), Apply a few Watts of RF and adjust the feed point to give a 1:1 SWR (slide the RG58 up and down the matching section). When the correct feed point has been found, solder the feeder connections. I dabbed some yacht varnish over the connections and the first couple of inches of the coax to stop water ingress down the feeder. Mount the aerial as high as possible; due to the construction materials the wind resistance is very low so it should survive the worst of any storms. N.B. I did try making a 4m slim Jim out of 450 ohm ladder feeder from a diagram posted on the web, however i could not get it to work correctly (maybe the two conductors in the ladder line are too close for 4m use, I also made one for 2m using the same ladder line from a design posted on the web and this one works great!) construction diagram pdf format
Barry Zarucki M0DGQ

A centre-fed "co-axial" dipole for 4m

by Tony Hawker G4CJZ

This design has the following advantages:
Low-cost components
Easy to set-up - nothing to adjust
No metalwork required, and only four soldered joints!

In contrast to the end-fed designs, which can be difficult to set up because of their narrow bandwidth, this alternative uses a low-impedance centre-feed, and hence offers a broader bandwidth.
In this design, the radiating half-wave section is formed from the centre conductor of a piece of co-axial cable, which is fed via two sections of its outer braiding which have been left in place.

The feed is essentially a delta-match, which makes use of the intrinsic capacitance of the two co-axial stubs.
At the ends of these delta-match sections, the braiding is soldered to the centre conductor.

 

 

The whole antenna is built inside lengths of 20mm plastic conduit, with the feed housed in an "inspection box" T-piece. This offers sufficient rigidity and weather-proofing, once the ends of the conduit are sealed with stoppers. A third section of conduit houses the feeder.

The flat VSWR response is characteristic of a low-impedance centre-feed.

The antenna may be clamped at the centre, either in vertical omni, or horizontal bi-directional configuration.

Original design by Tony G4CJZ, pictures by John GW4TQD.

Transverters

The most popular way of operating multimode on 4m is by using a 'transverter'. A transverter is simply a device which allows a transceiver designed for one amateur band to be used on another. Unfortunately most of the latest HF transceivers don't offer transverter facilities unless you are prepared to modify them yourself. Experience has found that some of the older 'Trio/Kenwood' transceivers such as the TS830S, TS430S, TS930S and TS940S are excellent as 'prime movers' for transverters. These provide all the interconnections on one 8 pin DIN connector and make for a convenient and professional installation. The TS430S in particular is particularly good in that when changing mode from CW to USB the transceiver changes frequency slightly so that a readable CW tone is received and not zero beat like most transceivers. This is useful on 4m as there are often either cross mode or changing of modes mid-QSO for the long haul contacts where QSB is often present. The Icom IC735 is also particularly good for transverting, as it offers a low-level transverter drive output. The Kenwood TS2000 has a transverter facility which allows display of the transmitted frequency. Minimum power output of 5W is automatically switched in when using this feature. There is also a separate receive input which can be used to avoid a relay to switch between receive and transmit chains. The Yaesu FT817 has a maximum power of 5 Watts, which can be set to even lower levels. This set can provide outputs at 28 or 144MHz. Spectrum Communications of Dorchester manufacture a range of products for the VHF bands. Since 1988, they have been producing 4m transverters in kit and ready-built form. The picture shows the latest design (2005) of transverter board with its companion 25W PA. Danish amateurs have developed a transverter design which is now available in kit form, see OZ2M's website. The kits cost 125 € including shipping within Europe, and profits go to support theOZ7IGY beacon project. With more than 175 kits sold this transverter is probably the best selling transverter kit these days. An accompanying 25 W PA kit is also available for 130 €. Mechanics & Electronics Inc, run by Gabi HA1YA, is now producing a 4m transverter and a range of valve RF PAs and associated control and power supply units. See his website for more details. Tony, I0JX has modified a Ten-Tec 6-metre transverter kit (which costs around 120 US dollars) to the 4-metre band. The project is described on Tony's website. Microwave Modules of Liverpool were well-known in the 1980s for their amplifiers and transverters. Many of these are still working, and appear on the second-hand market - check the dealers, or RadCom members' ads. These were constructed inside a compact Eddystone diecast box with either BNC or SO239 sockets for RF interconnections and a 5-pin locking DIN connector for DC and switching connections. Models were produced for use with 144MHz transceivers as well as HF transceivers using a 28MHz IF. They have been proved to be quite robust units over the years with many proving useful for both portable and home station use. They produce around 10W output and are suitable for all-mode operation. The input power required to drive these units is around 0.3 Watts: they were originally supplied with an external 15dB power attenuator (as shown in the photo), which dropped the output power from a 10W transceiver to a suitable level. The same company produced some new models in the mid-1990s, which are reputed to have a much better performance than the originals. Dave G4FRE has set up an archive of MM circuit information and Steve M0BPQ has provided a scan of the schematic. RN Electronics also produced transverters for the 4m band although these too are no longer available new. They were very similar in size and concept to the Microwave Modules devices and were also produced with IF's suitable for both 144MHz and HF transceivers. They were generally better than the Microwave Modules types in that some models gave 25W output and the receive sections were a little quieter. They are very rare on the second hand market however as very few were manufactured but again RadCom members' ads may turn one up. Mutek produced a nice dual-band transverter for the 50 and 70MHz bands with 25W output. They produced versions for 28MHz and 144MHz IFs but were quite expensive when new, but had a reputation for superb RF performance. Cirkit manufactured a kit for a 70MHz transverter designed by Tony Bailey G3WPO. This design was originally published in Ham Radio Today magazine around 1984. It was designed for use with a HF transceiver and used a 28MHz IF. It only produced around 0.5W output and so needed additional amplifier stages. Examples of these have been successfully built and used by Roger G3MEH and Ross G0WJR.