Marc PA1O has produced two documents, covering his analysis and simulation of the RX and TX band-pass filters, and the PA output and low-pass filter circuits.

His analysis highlights errors in some of the previously published component values, and suggests corrected values.
Marc's documents also include photographs of the PCB modifications, and his measurements of efficiency and reflection coefficient.

Marc's documents can be accessed from the Technical Features section.

Whilst engaged on benchmarking spectrum developments around the world, I came across this reference to a consultative process in Canada last year. It seems to me it opens the door for possible 4m activity in rural areas. It will be interesting to see what our VE readers think:

"In early 2006, Industry Canada has reallocated television channels 63 (764-770 MHz) and 68 (794-790 MHz) for public safety applications and the Department will consider the eventual release of channels 64 (770-776 MHz) and 69 (790-796 MHz) once the digital transition to lower cannels of existing television stations is well underway.

As part of the same decisions the Department has agreed to consider on a case by case basis the use of television channels 2 to 59 (54-72 MHz, 76-88 MHz, 174-216 MHz, 470-608 MHz and 614-746 MHz) for Advanced Communications Services in Remote Rural Communities. Proposals will be considered if they are at sufficient distance from major population centres, broadcasting facilities and their service contours so as not to cause them interference and on the condition that they do not constrain the provision of existing and new broadcasting services."

73s and good luck
Dave

PS Hope to work you Joe when I return from ET, 23 August!

4m in DL: I am qrv on 4m untill the beginning of September. Any JT6M (or FSK441) skeds most welcome especially for the next days (Perseids). I TX 69.995 with the call DI2AL and can RX any other 4m QRG. Loc. JO53CN. According to the authorities there is no chance for any other 4m activity from DL again, so better take your chance now....Pse sked proposals to info@DUBUS.de - ANY EI / GJ / IS0 qrv on 4m for Perseids??
In case of any Es condx to Northern DL pse call me on the phone: ++49 40 71097158, thank you! - 73 Joe, DL8HCZ/CT1HZE

For some considerable time a number of 4m enthusiasts including myself have been trying to encourage the Sysop at DX Summit (oh2w.kolumbus.com) to install 4m in the database search dropdown to no avail.

Late in June, I approached EA6VQ, the Sysop of "DX Sherlock 1.4 V-UHF QSO real time maps" and asked him if it was a realistic request to have a 70MHz map installed along with the existing 6m, 2m and 70cms maps. For a long while now DX Sherlock has had a 70MHz searchable database of spots. EA6VQ's response was positive and he asked for patience and time to undertake the changes.

I am happy to announce that DX Sherlock now has a 70MHz realtime map, fully operational. Now for the first time, we have a visual representation of the 70MHz spots appearing on cluster, with interconnecting lines which will graphically show where the propagation center is.

In order for the map to work correctly, one only need submit a spot to the clx, formatted in a particular way with the required basic information. Alternatively one can enter the spot directly on the DX Sherlock website.

The format required in the comment field to make the map work is:- [4/6digit locator][4/6digit locator]

The square brackets are NOT required but shown to illustrate the format in this article.

The web address for the map is :- http://www.vhfdx.net/spots/map.php?Frec=70

Paul GW8IZR adds: "the users of the Livemuf website and downloadable Livemuf application have had this facility for several years. All of these reporting tools are excellent and each author should receive due credit.

As with any of the tools "path centre" is only part of the story and the images require some interpretation. Looking at filtered output from the dx cluster limits the ability of a user to interpret the data."

If a new design for a small desk top/portable expedition size solid state amplifier covering only 2m, 4m and 6m was to be available what features would you look for? The reason that I am asking is that I have had a very interesting exchange of emails with a European designer/manufacturer. He is certainly becoming interested in producing such a model and today put the following basic criteria to me: Maximum power 600 or 1000 W? Separate inputs for every band? Separate outputs for every band? All outputs 50 ohm? CAT facility? One or two transceivers? Please email me your own answers/suggestions. All I ask is that you keep to main features and use a brief, bullet point style. Thanks in advance.

Following a request of Luca Ferrara IK0YYY, the Italian Ministry of Communications, in coordination with the Ministry of Defense, has reportedly authorized on July 12th 2007 an amateur radio experimental campaign on the 70-MHz band (4 meters) up to December 31st 2007 (news to be officially disclosed by the recipients of the formal authorization) . Such campaign is being carried out under the technical coordination of  Piero Tognolatti I0KPT, Full Professor of the Electromagnetic Fields Group and Director of the Electrical Engineering and Information Theory Department of the University of l’Aquila.

• The technical parameters are:
• Modes: all (SSB, CW, AM, FM, RTTY, digital modes, etc.)
• Frequencies:
  70.100 MHz ± 12.5 kHz
  70.200 MHz ± 12.5 kHz
  70.300 MHz ± 12.5 kHz
• Maximum RF power: 25W EIRP
• Operational area: the whole Italian territory except for a 30 km strip from the Austria, France and Switzerland borders
• Antenna types: omnidirectional and directional

The experimental campaign, whose  results will be published after its conclusion, is reportedly open to all Italian radioamateurs.

A beacon transmitting on frequency 70.088 MHz (mark) with FSK modulation (500-Hz upward shift) has already been activated. This is at the very low edge of the authorized band.

We wish to express our warm thanks to the Italian Ministry of Communications (Ing. F. Troisi and Dr. A. Cascio) and to the Italian Ministry of Defense, who, despite the administrative and operational hurdles, have once more given the Italian radioamateurs a clear sign of esteem and credibility. Sincere thanks are also given to the Università of L'Aquila (Prof. P. Tognolatti) for its exquisite and effective cooperation.

Luca Ferrara IK0YYY – Antonio Vernucci I0JX

I had a discussion with officials of National Telecom Authority regarding HA experiment radio permit. The officials explained clearly that we can have contacts with foreigner radio amateurs. We must exclusively identify ourselves by 70MXXX call name at beginning of the contact and at the end. Inside the so called “radio waive propagation experiment” we are allowed to openly say our ham radio callsign. Last evening I was happy to have two way 4m experiment with CT1HZE Joe and proudly share with all of you the audio recordings: http://holman.ehc.hu/ct1hze.mp3

I ask you to understand our special conditions and accept our 70MXXX caller ID. In the QSO we will say our callsign. This kind of experiment will never be officially considered part of amateur service. However, I do consider the experiment part of my ham radio activity and will send QSL cards stating both call name and ham callsign. What you are considering is up to you.

Thank you for your understanding and look forward to much radio wave propagation experiments
GL and 73, de 70M5PT alias HA5PT, Tamas

Budapest, 29 June, 2007.
HA5HRK
An experimental radio licence was signed and issued today for Haros Radioklub that permits radio usage of the 70 MHz band for the first time in Hungary for 30 radio amateurs.
The licence is valid for a period of 30 days starting 1 July 2007. The aim of the experiment is to study propagation of radio waves in the 70 MHz band where all FM broadcasting was stopped in February. The frequency range permitted for the experiment is 70.000 - 70.500 MHz, and the licence is valid for all operating modes, CW, SSB, narrow band FM and digital modes like JT6M. Maximum effective radiated power (ERP) is limited to 1kW.
The original request was submitted in April. In spite of lack of Radioamateur service allocation of the band the National Communications Authority responded quickly and cooperatively. In the experiment we have to identify ourselves by “call name” beside our ham radio callsign. The call name is composed by a prefix “70m” and a suffix of amateur radio callsign.

70M1BVC  HG1BVC 70012.5kHz JN87FI beacon
70M1FV   HA1FV 
70M1WD   HA1WD 
70M1XY   HA1XY 
70M1YA   HA1YA 
70M2RD   HA2RD 
70M2SU   HA2SU 
70M2SX   HA2SX 
70M3MQ   HA3MQ 
70M4XG   HA4XG 
70M5CJ   HA5CJ 
70M5CJ2  HA5CJ/P 
70M5CUT  HG5CUT 
70M5HRK  HA5HRK 
70M5KDR  HA5KDR 
70M5KDR2 HA5KDR/P 
70M5LV   HA5LV 
70M5MA   HA5MA 
70M5PT   HA5PT 
70M5TI   HA5TI 
70M5UY   HA5UY 
70M5XA   HG5XA 
70M7BVB  HG7BVB 70037.5kHz JN97QK beacon
70M7CR   HA7CR 
70M8BI   HA8BI 
70M8BI2  HA8BI/P 
70M8BR   HA8BR 
70M8BS   HA8BS 
70M8KL   HA8KL 
70M8MV   HA8MV 
70M9MDP  HA9MDP

We hope that these radio amateurs, with their experience, international reputation and the geographical location of their stations mean guarantee to the success and professionalism of the experiment. Our long term goal is to contribute to the joint efforts of 70MHz allocation for amateur radio service in Hungary and worldwide.

http://holman.ehc.hu/70MHZ_permit.jpg

The Coulsdon Amateur Transmitting Society Weekly Net operates on Wednesday evenings on 70.425 MHz from 2100hrs local time. Listen for club station M1FUR operated by myself, G0KZT. If you hear us, please call in.

Details of other regular net activity may be found here: www.70mhz.org/nets.htm

Anacom have publish on website is position about the 4m band:

pse look :

http://www.anacom.pt/template12.jsp?categoryId=244864

like was expected, more 3 months will be permited, for thouse who prove activity.

no more 70mhz in CT after 31 Agost 2007

73's All.