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L-7 Internal Low Pass Set?

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John N4YE All Messages By This Member #70228 I discovered what I think is an extra low pass circuit from an L-7 I owned years ago. Hopefully someone can use it. -- 73 John?N9FCA E647C988-EC39-4679-8A44-CF451F78B059.jpeg
aa5wg All Messages By This Member #70236 Hi john - N9FCA Is your L-7 low pass circuit still available? Thank you. Chuck - AA5WG
John N4YE All Messages By This Member #70241 Hi Chuck, It is. -- 73 John?N9FCA
aa5wg All Messages By This Member #70250 Hi John, Thanks for your reply. Would you contact me please at aa5wg@...?or? 231-668-1115. Sir, thank you. 73, Chuck?
Jim VE7RF All Messages By This Member #70270 What was it used for...to inhibit? amplifying > 23 mhz ???
VE7PS All Messages By This Member #70271 Jim: You won't find that low pass filter board in an "Export" (like Canada) model.? It was installed in the US models to inhibit 10m operation in a fruitless attempt?by the FCC to stop CB-ers from using ham amps back in the late '70's and 80's.? That's why on the US amps they do not have 10m marked on the front panel.? You could just short the filter out or pull it completely?and connect the jumper. Not sure why anyone would want to buy one? 73 Peter VE7PS toggle quoted message Show quoted text On Tue, Mar 28, 2023 at 8:13?AM Jim VE7RF <jim.thom@...> wrote: What was it used for...to inhibit? amplifying > 23 mhz ???
Steve Wedge, W1ES/4 All Messages By This Member #70273 I was wondering the same thing, Peter. The parts may be of some use in other applications. Steve Wedge, W1ES/4 Time flies like an arrow.? Fruit flies like a banana. Sent with secure email. toggle quoted message Show quoted text ------- Original Message ------- On Tuesday, March 28th, 2023 at 11:32 AM, VE7PS <ve7ps@...> wrote: Jim: You won't find that low pass filter board in an "Export" (like Canada) model. It was installed in the US models to inhibit 10m operation in a fruitless attempt by the FCC to stop CB-ers from using ham amps back in the late '70's and 80's. That's why on the US amps they do not have 10m marked on the front panel. You could just short the filter out or pull it completely and connect the jumper. Not sure why anyone would want to buy one? 73 Peter VE7PS On Tue, Mar 28, 2023 at 8:13?AM Jim VE7RF <jim.thom@...> wrote: What was it used for...to inhibit amplifying > 23 mhz ??
Leland L. Bahr All Messages By This Member #70275 开云体育 I bought a L7 back then new and then converted it to be an export model.? You had to change one input silver mica, re-tune it, remove a set screw so the band switch would move to the 10 meter position and then remove the filter which was on a PC board along with it's attached input and out put coaxial cables.? You then put in a new longer piece of coax connecting the amp input SO-239 to the input of the amplifier.? Your amp was now an export model without the 10 meter label on the band switch. Lee, w0vt On 3/28/2023 10:37 AM, Steve Wedge, W1ES/4 via groups.io wrote: toggle quoted message Show quoted text I was wondering the same thing, Peter. The parts may be of some use in other applications. Steve Wedge, W1ES/4 Time flies like an arrow.? Fruit flies like a banana. Sent with secure email. ------- Original Message ------- On Tuesday, March 28th, 2023 at 11:32 AM, VE7PS <ve7ps@...> wrote: Jim: You won't find that low pass filter board in an "Export" (like Canada) model. It was installed in the US models to inhibit 10m operation in a fruitless attempt by the FCC to stop CB-ers from using ham amps back in the late '70's and 80's. That's why on the US amps they do not have 10m marked on the front panel. You could just short the filter out or pull it completely and connect the jumper. Not sure why anyone would want to buy one? 73 Peter VE7PS On Tue, Mar 28, 2023 at 8:13?AM Jim VE7RF <jim.thom@...> wrote: What was it used for...to inhibit amplifying > 23 mhz ??
Jim W7RY #70278 开云体育 Yes. It was installed in a L7 amplifier to prevent it from being driven on 10-11 meters. Not very useful I would say.... Most get tossed in the trash.. Which they should be. 73, Jim W7RY On 3/28/2023 10:13 AM, Jim VE7RF wrote: What was it used for...to inhibit? amplifying > 23 mhz ??? -- Thanks and 73, Jim W7RY
Jim VE7RF All Messages By This Member #70301 On the heath? SB-221,? it too, also has the silly LP filter.? It also has only a 4 position bandswitch for both the kw tank output...and also the tuned input.? ?So no way to add 10m to it, unless you dumped the 15m position, and tapped it for 10m, then used correct values for a 10m tuned input.? ?When the filter is removed from the SB-221,? it screws up all the existing PI net tuned inputs.? Most 11m ops would simply bypass the bandswitch for the output anyway, then just install a monoband 10m coil, directly between the tune and load caps.? Then modify the 15m tuned input for 11m. Then proceed to blow the amp up anyway...while using AM.? ?With amp tuned to say 1200 w pep out...and a 300 watt? UN-modulated cxr, the? Un modulated cxr eff is only 25%..and the anode diss is triple that, or 900 watts...and bye bye? 3-500Z's.? The fan in it is too small for 900 w CCS anode diss.? The L4B / L7 isn't much better on AM.? ?The controlled cxr? AM scheme used on the 4 line drake rigs worked good on AM..and was compatible with the L4B / L7.?

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