Incorporating G2DYM Aerials & Garex Electronics

TVI FILTERS – 1 March 2017

 Please email or phone for a quote or to place an order by credit/debit card or for a Paypal money request. Purchase of several items is likely to make a saving on postage. Tel 01305 262250

Orders & quote requests to  jean@spectrumcomms.co.uk

Technical queries to  tony@spectrumcomms.co.uk


High Pass Filter HPF175. Designed for use where television is broadcast on VHF, such as in some Scandinavian Countries and in Australia. It gives over 60dB of attenuation from DC to 90MHz and even 27dB of attenuation to signals on 146MHz.  The unit does not include a braid breaker and signals could still cause breakthrough due to pick up on the braid of the TV downlead.  Price 17.50 UK, 18.50 EU, 20.00 World. Including P&P.  




HPF450 & HPF550.  The HPF450 has passband with a -6dB point at about 450MHz.  It rejects signals from DC to 200MHz by 60dB.  This includes HF, CB, 6m, 4m, 2m, marine,  & taxi.  Passband ripple 455-1000MHz 4dB. The HPF550 is a modified version to allow digital signals above 600MHz to pass and to reduce breakthrough by analogue signals at the bottom of the band. Price 15.50 UK, 17.50 EU, 18.50 World. Including P&P.  Quantity discounts available.

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HPF-500 (or HPF-6) TVI filter with passband above 500MHz.  Rejects signals from DC to 30MHz and from 100 to 200MHz by 60dB. Sharp skirt response falls from cut-off at 500Mhz to notch of -70dB at 420MHz. Seriously reduces interference from 70cm Amateurs and TETRA PMR. Price 28.50 UK, 34.50 EU, 35.00 World. Including P&P.   Quantity discounts available.

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BPF-100 with a passband of 80-120MHz to accept the VHF broadcast band and reject above and below this range.  Particularly useful to reduce interference to car radios from engine management units. Available with car radio connectors or with TV connectors for use with aerial fed domestic broadcast receivers. Price 15.50 UK, 17.00 EU, 18.50 World. Including P&P.


These filters are designed to notch-out one specific band that is causing interference. They are available as NF14, NF21, NF27, NF29, NF51, NF70, NF145, and NF433.  Other frequencies are available to order.   Price 15.50 UK, 17.00 EU, 18.50 World. Including P&P.


The rights to the former AKD range of Blackline filters was acquired with other products on the purchase of Garex Electronics on 1 December 2011.  The HPFS filter when analysed had a missing component from the usual network.   When the missing component was added the filter performance improved considerably. This filter also included a 1:1 ratio transformer to act as a braid breaker, preventing interference flowing down the screen of the coax and continuing past the filter.  The filter with the additional component was given the code HPF3.  

Subsequently the HPF3 was further developed to include low pass networks in both inner and outer lines of the coax.  A new printed circuit board was laid out to improve unwanted coupling and to reduce unwanted inductance effects.   Now with equal currents flowing in both filter sections at the passband frequencies the inner and outer coax connections were reversed between input and output.  This then achieved the required braid breaker function without the need for the 1:1 transformer.  The new filter was given the code HPF450 and has now completely superceded the HPF3, which is discontinued.