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Use your microwave transverter

for DATV!

It is really easy to use an existing narrowband

transverter with current home-constructed digital

ATV (DATV) equipment to transmit and receive

DATV on the microwave bands. Both of the

commonly-used digital ATV signal sources, the

Portsdown transmitter

[1]

and DATV Express

[2]

can generate a DATV signal on any frequency

between 70MHz and 1500MHz. Similarly,

the MiniTioune DATV receiver can tune from

144MHz to 2650MHz.

The main effort required to put such a system

together is in arranging suitable switching

between receive and transmit whilst retaining

the narrowband capability, which is very useful

for establishing contact and calibrating frequency

and dish heading against beacons. The other

factor that needs to be considered is getting the

drive level right: this often means bypassing

the input attenuator on the transmit side of

the transverter so that the 5mW or so from the

DATV exciter drives the transverter and PA to

the correct level. The main components can be

seen in

Figure 1

.

47GHz success

Dave, G4FRE has recently built a Portsdown

transmitter and used the transverter approach to

conduct tests on 24GHz and 47GHz. During his

most recent test he transmitted about 0.2mW of

DATV from a 20dB horn on 47GHz and received

it 30km away (

Figure 2

) using a 30cm dish on

a Pasolink-based receiver

[3]

with an IF near

70cm.

Activity weekends

ATV activity is thriving again and this has

been encouraged by the monthly ATV Activity

Weekends. The Sundays are particularly popular.

In January there were 9 stations active in the

south-west. Contacts took place using digital ATV

on 146MHz, 10GHz and 24GHz. Additionally, a

number of stations tested their 5.6GHz FM ATV

equipment, including Shaun, G8VPG/P and I

(see

Photo 1

).

Adrian, G4UVZ achieved good results with

an indoor aerial on 5.6GHz.

Photo 2

shows the

setup he used to receive G8GTZ/P through his

shack window.

News about planned ATV activity is generally

posted on the BATC Forum

[4]

. No log-in is

required to view what is going on. During the

day talkback is generally on 144.75MHz FM.

Stations also use the excellent DXSpot.TV

website

[5]

for coordination. The next Activity

Weekends are on 10/11 March and 7/8 April.

Websearch

[1]

https://wiki.batc.org.uk/The_Portsdown_

Transmitter

[2]

https://datv-express.com

[3]

http://g4fre.com/pasolink2.pdf

[4]

https://forum.batc.org.uk/viewforum.

php?f=75

[5]

https://www.dxspot.tv/

Dave Crump, G8GKQ

dave.g8gkq@gmail.com

ATV

Regulars

80

March 2018

Portsdown

ATV

transmitter

Laptop

PC MiniTiouner

Narrowband rig

Attenuator

Splitter

Transmit converter and PA

Receive converter

LO

T/R

switch

T/R

switch

Voice/TV

switch

Existing microwave transverter

PHOTO 2:

G4UVZ’s 5.6GHz station receiving

G8GTZ/P.

PHOTO 1:

G8GKQ/P with 146MHz, 5.6GHz, 10GHz and 24GHz.

FIGURE 1:

Using a normal microwave transverter for digital ATV.

FIGURE 2:

G4FRE received at 30km on 47GHz.